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1.  Soy consumption during menopause 
In developed countries, the life expectancy of women is currently extending more than 30 years beyond the age of menopause. The menopausal transition is often associated with complaints. The conflicting results on the effectivity of phytoestrogens to alleviate menopausal symptoms. This discrepancy in treatment effect may be due to the large interindividual variation in isoflavone bioavailability in general and equol production in particular. Equol, a microbial metabolite of daidzein, has been hypothesized as a clue to the effectiveness of soy and its isoflavones, but only about 30-50% of the population harbor an intestinal microbial ecosystem supporting the conversion of daidzein into equol.
There is much concern on breast cancer, since this incidence of this disease increases with age. There is indication that soy phytoestrogens may decrease this breast cancer incidence. In order to evaluate the estrogenic potential of these exposure levels, we studied the isoflavone-derived E2α- and E2β-equivalents (i.e. 17β-estradiol (E2)-equivalents towards ERα and ERβ, respectively) in human breast tissue. Total isoflavones showed a breast adipose/glandular tissue distribution of 40/60 and their derived E2β-equivalents exceeded on average 21 ± 4 and 40 ± 10 times the endogenous E2 concentrations in corresponding adipose and glandular biopsies, respectively, whereas the E2α/E2 ratios were 0.4 ± 0.1 and 0.8 ± 0.2 in adipose and glandular breast tissue, respectively. These calculations suggest that, at least in this case, soy consumption could elicit partial ERβ agonistic effects in human breast tissue. We are currently characterizing the differential activation of estrogen-responsive genes between dietary isoflavones, the chemopreventive selective ER modulators tamoxifen and raloxifene and exogenous estrogens in a controlled dietary intervention trial that integrates data on the exposure to estrogenically active compounds, expression of isoflavone and estrogen target genes, and epigenetic events.
During the menopause, there is a close relation between the drop in serum estrogen and negative metabolic changes such as the increase in bone resorption and negative change in the serum lipid profile. Randomized controlled trials measuring bone turnover markers in menopausal women revealed that soy isoflavone supplements significantly but moderately decrease the bone resorption marker urinary deoxypyridinoline without significant effects on the bone formation markers serum bone alkaline phosphatase and osteocalcin.
PMCID: PMC3991438  PMID: 24753886
Bone resorption; estrogens; isoflavones; lipid profile; menopause; phytoestrogens; soy
2.  Cruciferous Vegetables and Human Cancer Risk: Epidemiologic Evidence and Mechanistic Basis 
Cruciferous vegetables are a rich source of glucosinolates and their hydrolysis products, including indoles and isothiocyanates, and high intake of cruciferous vegetables has been associated with lower risk of lung and colorectal cancer in some epidemiological studies. Glucosinolate hydrolysis products alter the metabolism or activity of sex hormones in ways that could inhibit the development of hormone-sensitive cancers, but evidence of an inverse association between cruciferous vegetable intake and breast or prostate cancer in humans is limited and inconsistent. Organizations such as the National Cancer Institute recommend the consumption of 5–9 servings of fruits and vegetables daily, but separate recommendations for cruciferous vegetables have not been established. Isothiocyanates and indoles derived from the hydrolysis of glucosinolates, such as sulforaphane and indole-3-carbinol (I3C), have been implicated in a variety of anticarcinogenic mechanisms, but deleterious effects also have been reported in some experimental protocols, including tumor promotion over prolonged periods of exposure. Epidemiological studies indicate that human exposure to isothiocyanates and indoles through cruciferous vegetable consumption may decrease cancer risk, but the protective effects may be influenced by individual genetic variation (polymorphisms) in the metabolism and elimination of isothiocyanates from the body. Cooking procedures also affect the bioavailability and intake of glucosinolates and their derivatives. Supplementation with I3C or the related dimer 3,3′-diindolylmethane (DIM) alters urinary estrogen metabolite profiles in women, but the effects of I3C and DIM on breast cancer risk are not known. Small preliminary trials in humans suggest that I3C supplementation may be beneficial in treating conditions related to human papilloma virus infection, such as cervical intraepithelial neoplasia and recurrent respiratory papillomatosis, but larger randomized controlled trials are needed.
PMCID: PMC2737735  PMID: 17317210
Brassica; glucosinolates; genetic polymorphisms; isothiocyanates; indole-3-carbinol; epigenetics
3.  Estrogen Metabolism and Risk of Breast Cancer in Postmenopausal Women 
Estrogens are recognized causal factors in breast cancer. Interindividual variation in estrogen metabolism may also influence the risk of breast cancer and could provide clues to mechanisms of breast carcinogenesis. Long-standing hypotheses about how estrogen metabolism might influence breast cancer have not been adequately evaluated in epidemiological studies because of the lack of accurate, reproducible, and high-throughput assays for estrogen metabolites.
We conducted a prospective case–control study nested within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO). Participants included 277 women who developed invasive breast cancer (case subjects) and 423 matched control subjects; at PLCO baseline, all subjects were aged 55–74 years, postmenopausal and not using hormone therapy, and provided a blood sample. Liquid chromatography–tandem mass spectrometry was used to measure serum concentrations of 15 estrogens and estrogen metabolites, in unconjugated and conjugated forms, including the parent estrogens, estrone and estradiol, and estrogen metabolites in pathways defined by irreversible hydroxylation at the C-2, C-4, or C-16 positions of the steroid ring. We calculated hazard ratios (HRs) approximating risk in highest vs lowest deciles of individual estrogens and estrogen metabolites, estrogens and estrogen metabolites grouped by metabolic pathways, and metabolic pathway ratios using multivariable Cox proportional hazards models. All statistical tests were two-sided.
Nearly all estrogens, estrogen metabolites, and metabolic pathway groups were associated with an increased risk of breast cancer; the serum concentration of unconjugated estradiol was strongly associated with the risk of breast cancer (HR = 2.07, 95% confidence interval [CI] = 1.19 to 3.62). No estrogen, estrogen metabolite, or metabolic pathway group remained statistically significantly associated with the risk of breast cancer after adjusting for unconjugated estradiol. The ratio of the 2-hydroxylation pathway to parent estrogens (HR = 0.66, 95% CI = 0.51 to 0.87) and the ratio of 4-hydroxylation pathway catechols to 4-hydroxylation pathway methylated catechols (HR = 1.34, 95% CI = 1.04 to 1.72) were statistically significantly associated with the risk of breast cancer and remained so after adjustment for unconjugated estradiol.
More extensive 2-hydroxylation of parent estrogens is associated with lower risk, and less extensive methylation of potentially genotoxic 4-hydroxylation pathway catechols is associated with higher risk of postmenopausal breast cancer.
PMCID: PMC3283536  PMID: 22232133
4.  Plasma Enterolactone and Breast Cancer Risk in the Nurses’ Health Study II 
Lignans are plant-based phytoestrogens with both estrogenic and anti-estrogenic properties that may be important for breast carcinogenesis. Retrospective studies have observed decreased breast cancer risk associated with high circulating enterolactone concentrations, a biomarker of lignan intake, but results from prospective studies are conflicting.
To prospectively examine this association, we measured plasma enterolactone levels in 802 breast cancer cases and 802 matched controls nested among predominantly premenopausal women in the Nurses’ Health Study II (NHSII) cohort. We used conditional logistic regression and polytomous logistic regression models, adjusting for known breast cancer risk factors, to calculate relative risks (RR) and 95% confidence intervals (CI).
Compared to women with enterolactone concentrations ≤ 4nmol/L, the multivariate adjusted RRs for breast cancer were 1.18 (95% CI: 0.86–1.62), 0.91 (95% CI: 0.66–1.25), and 0.96 (95% CI: 0.70–1.33) for women with enterolactone levels in the 2nd to the 4th quartiles, respectively; Ptrend=0.60. Results were similar across tumors defined by estrogen and progesterone receptor status. Among premenopausal women with follicular estradiol levels below the median (<47 pg/mL), women in the highest category of enterolactone levels had a 51% lower breast cancer risk compared to those in the lowest category (95% CI: 0.27–0.91); Ptrend=0.02. No association was observed among women with high follicular estradiol levels (≥47 pg/mL), (comparable RR=1.39, 95% CI: 0.73–2.65; Pinteraction=0.02).
We did not observe an overall association between plasma enterolactone and breast cancer risk in a large nested case-control study of US women. However, a significant inverse association was observed among premenopausal women with low follicular estradiol levels, suggesting that enterolactone may be important in a low estrogen environment. This should be confirmed in future studies.
PMCID: PMC3736336  PMID: 23760859
enterolactone; lignan; breast cancer; biomarker; prospective study; premenopausal
5.  Effects of a Flaxseed-Derived Lignan Supplement in Type 2 Diabetic Patients: A Randomized, Double-Blind, Cross-Over Trial 
PLoS ONE  2007;2(11):e1148.
Flaxseed consumption has been shown to improve blood lipids in humans and flaxseed-derived lignan has been shown to enhance glycemic control in animals. The study aimed to investigate the effect of a flaxseed-derived lignan supplement on glycemic control, lipid profiles and insulin sensitivity in type 2 diabetic patients.
Methodology/Principal Findings
This was a randomized, double-blind, placebo-controlled, cross-over trial and it was conducted between April and December 2006 in Shanghai, China. Seventy-three type 2 diabetic patients with mild hypercholesterolemia were enrolled into the study. Patients were randomized to supplementation with flaxseed-derived lignan capsules (360 mg lignan per day) or placebo for 12 weeks, separated by an 8-week wash-out period. HbA1c, lipid profiles, insulin resistance index and inflammatory factors were measured. Sixty-eight completed the study and were included in the analyses. The lignan supplement significantly improved glycemic control as measured by HbA1c (-0.10±0.65 % vs. 0.09±0.52 %, P = 0.001) compared to placebo; however, no significant changes were observed in fasting glucose and insulin concentrations, insulin resistance and blood lipid profiles. Urinary excretion of lignan metabolites (enterodiol and enterolactone) was significantly higher after the lignan supplement intervention compared to baseline (14.2±18.1 vs. 1.2±2.4 µg/mL, P<0.001). Data also suggested minimal competition between lignan and isoflavones for bioavailability when measured by the excretion concentrations.
Daily lignan supplementation resulted in modest, yet statistically significant improvements in glycemic control in type 2 diabetic patients without apparently affecting fasting glucose, lipid profiles and insulin sensitivity. Further studies are needed to validate these findings and explore the efficacy of lignans on type 2 diabetes.
Trial Registration NCT00363233
PMCID: PMC2048577  PMID: 17987126
6.  Dietary lignan intake and postmenopausal breast cancer risk by estrogen and progesterone receptor status 
Studies conducted in Asian populations have suggested that high consumption of soy-based foods that are rich in isoflavone phytoestrogens is associated with a reduced risk of breast cancer. However, the potential associations of other dietary phytoestrogens — i.e., the lignans or their bioactive metabolites, the enterolignans — with the risk of breast cancer are unclear.
We prospectively examined associations between the risk of postmenopausal invasive breast cancer and dietary intakes of four plant lignans (pinoresinol, lariciresinol, secoisolariciresinol, and matairesinol) and estimated exposure to two enterolignans (enterodiol and enterolactone), as measured with a selfadministered diet history questionnaire, among 58 049 postmenopausal French women who were not taking soy isoflavone supplements. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated using multivariable Cox proportional hazards regression models. Analyses were further stratified by the combined estrogen and progesterone receptor (ER/PR) status of the tumors. Statistical tests were two-sided.
During 383 425 person-years of follow-up (median follow-up, 7.7 years), 1469 cases of breast cancer were diagnosed. Compared with women in the lowest intake quartiles, those in the highest quartile of total lignan intake (>1395 μg/day) had a reduced risk of breast cancer (RR = 0.83, 95% CI = 0.71 to 0.95, Ptrend = .02, 376 versus 411 cases per 100 000 person-years), as did those in the highest quartile of lariciresinol intake (RR = 0.82, 95% CI = 0.71 to 0.95, Ptrend = .01). The inverse associations between phytoestrogen intakes and postmenopausal breast cancer risk were limited to ER- and PR-positive disease (e.g., RR for highest versus lowest quartiles of total plant lignan intake = 0.72, 95% CI = 0.58 to 0.88, Ptrend = .01, 174 versus 214 cases per 100 000 person-years, and RR for highest versus lowest quartiles of total enterolignan level = 0.77, 95% CI = 0.62 to 0.95, Ptrend = .01, 164 versus 204 cases per 100 000 person-years).
High dietary intakes of plant lignans and high exposure to enterolignans were associated with reduced risks of ER- and PR-positive postmenopausal breast cancer in a Western population that does not consume a diet rich in soy.
PMCID: PMC2292813  PMID: 17374837
Adult; Aged; Breast Neoplasms; chemistry; prevention & control; Carcinoma; Ductal; Breast; prevention & control; Diet Surveys; Female; Follow-Up Studies; Food Habits; France; Humans; Lignans; administration & dosage; Middle Aged; Multivariate Analysis; Odds Ratio; Postmenopause; Proportional Hazards Models; Prospective Studies; Questionnaires; Receptors; Estrogen; analysis; Receptors; Progesterone; analysis; Reproducibility of Results; Research Design; Risk Assessment
7.  Lignans and breast cancer risk in pre- and post-menopausal women: meta-analyses of observational studies 
British Journal of Cancer  2009;100(9):1492-1498.
Phyto-oestrogens are plant compounds structurally similar to oestradiol, which have been proposed to have protective effects against breast cancer. The main class of phyto-oestrogens in the Western diet is lignans. Literature reports on the effect of lignans in breast cancer risk have been conflicting. We performed three separate meta-analyses to examine the relationships between (i) plant lignan intake, (ii) enterolignan exposure and (iii) blood enterolactone levels and breast cancer risk. Medline, BIOSIS and EMBASE databases were searched for publications up to 30 September 2008, and 23 studies were included in the random effects meta-analyses. Overall, there was little association between high plant lignan intake and breast cancer risk (11 studies, combined odds ratio (OR): 0.93, 95% confidence interval (95% CI): 0.83–1.03, P=0.15), but this association was subjected to marked heterogeneity (I2=44%). Restricting the analysis to post-menopausal women, high levels of plant lignan intake were associated with reduced breast cancer risk (7 studies, combined OR: 0.85, 95% CI: 0.78, 0.93, P<0.001) and heterogeneity was markedly reduced (I2=0%). High enterolignan exposure was also associated with breast cancer (5 studies, combined OR: 0.73, 95% CI: 0.57, 0.92, P=0.009) but, again, there was marked heterogeneity (I2=63%). No association was found with blood enterolactone levels (combined OR: 0.82, 95% CI: 0.59–1.14, P=0.24). In conclusion, plant lignans may be associated with a small reduction in post-menopausal breast cancer risk, but further studies are required to confirm these results.
PMCID: PMC2694431  PMID: 19337250
plant lignans; enterolignans; breast cancer risk
8.  Soy intake is associated with increased 2-hydroxylation and decreased 16α-hydroxylation of estrogens in Asian-American women 
In Asian women, soy consumption is associated with reduced breast cancer risk, perhaps due to effects on estrogen production or metabolism. In a sample of Asian-American women, we investigated associations of usual adult soy intake with urinary concentrations of 15 estrogens and estrogen metabolites (EM) measured using liquid chromatography-tandem mass spectrometry.
Participants included 430 Chinese-, Japanese-, and Filipino-American women, aged 20–55 years, and living in San Francisco-Oakland (CA), Los Angeles (CA) or Oahu (HI). They were postmenopausal (n=167) or premenopausal in luteal phase (n=263) when they collected 12-hour urines. Robust linear regression was used to assess soy tertiles as predictors of log-transformed EM measures. Individual and grouped EM were considered as concentrations (pmol/mg creatinine) and as percentages of total EM (%EM).
Factor analysis confirmed that EM groups defined by metabolic pathways appropriately captured covariation in EM profiles. Total EM concentrations (pmol/mg creatinine) were not significantly associated with soy in pre- or postmenopausal women. Among all women, %2-hydroxylated EM and %4-hydroxylated EM were 16.3% higher (ptrend= 0.02) and 18.6% higher (ptrend= 0.03) in highest vs. lowest soy tertiles. In contrast, %16-hydroxylated EM were 10.6% lower (ptrend< 0.01). Results were consistent across ethnic and menopausal groups and after adjustment for Westernization measured by birthplace (Asia or U.S.).
Findings suggest that regular soy intake is associated with increased ratios of 2:16-pathway EM and with higher relative levels of 4-hydroxylated EM. Observed variations in estrogen metabolism may modify breast cancer risk.
PMCID: PMC2759852  PMID: 19789363
soy; isoflavones; estrogens; estrogen metabolite; urine
9.  Estrogen metabolism and mammographic density in postmenopausal women: a cross-sectional study 
Prospective studies have consistently found that postmenopausal breast cancer risk increases with circulating estrogens; however, findings from studies of estrogens and mammographic density (MD), an intermediate marker of breast cancer risk, have been inconsistent. We investigated the cross-sectional associations of urinary estrogens, and their 2-, 4-, and 16-hydroxylated metabolites with MD.
Postmenopausal women without breast cancer (n=194), ages 48-82 years, and reporting no current menopausal hormone therapy use were enrolled at a clinic in Western NY in 2005. Urinary estrogens and estrogen metabolites were measured using mass spectrometry. Percent MD and dense area (cm2) were measured using computer-assisted analyses of digitized films. Linear regression models were used to estimate associations of log-transformed estrogen measures with MD while adjusting for age, body mass index (BMI), parity, and past hormone therapy use.
Urinary concentrations of most individual estrogens and metabolites were not associated with MD; however, across the interdecile range of the ratio of parent estrogens (estrone and estradiol) to their metabolites, MD increased by 6.8 percentage points (p=0.02) and dense area increased by 10.3 cm2 (p=0.03). Across the interdecile ranges of the ratios of 2-, 4-, and 16-hydroxylation pathways to the parent estrogens, MD declined by 6.2 (p=0.03), 6.4 (p=0.04), and 5.7 (p=0.05) percentage points, respectively. All associations remained apparent in models without adjustment for BMI.
In this study of postmenopausal women, less extensive hydroxylation of parent estrogens was associated with higher MD.
Hydroxylation of estrogens may modulate postmenopausal breast cancer risk through a pathway involving MD.
PMCID: PMC3436977  PMID: 22736791
Estrogens; metabolism; mammography; breast neoplasms; risk factors; human; female; middle-aged
10.  Promotional Tone in Reviews of Menopausal Hormone Therapy After the Women's Health Initiative: An Analysis of Published Articles 
PLoS Medicine  2011;8(3):e1000425.
Adriane Fugh-Berman and colleagues analyzed a selection of published opinion pieces on hormone therapy and show that there may be a connection between receiving industry funding for speaking, consulting, or research and the tone of such opinion pieces.
Even after the Women's Health Initiative (WHI) found that the risks of menopausal hormone therapy (hormone therapy) outweighed benefit for asymptomatic women, about half of gynecologists in the United States continued to believe that hormones benefited women's health. The pharmaceutical industry has supported publication of articles in medical journals for marketing purposes. It is unknown whether author relationships with industry affect promotional tone in articles on hormone therapy. The goal of this study was to determine whether promotional tone could be identified in narrative review articles regarding menopausal hormone therapy and whether articles identified as promotional were more likely to have been authored by those with conflicts of interest with manufacturers of menopausal hormone therapy.
Methods and Findings
We analyzed tone in opinion pieces on hormone therapy published in the four years after the estrogen-progestin arm of the WHI was stopped. First, we identified the ten authors with four or more MEDLINE-indexed reviews, editorials, comments, or letters on hormone replacement therapy or menopausal hormone therapy published between July 2002 and June 2006. Next, we conducted an additional search using the names of these authors to identify other relevant articles. Finally, after author names and affiliations were removed, 50 articles were evaluated by three readers for scientific accuracy and for tone. Scientific accuracy was assessed based on whether or not the findings of the WHI were accurately reported using two criteria: (1) Acknowledgment or lack of denial of the risk of breast cancer diagnosis associated with hormone therapy, and (2) acknowledgment that hormone therapy did not benefit cardiovascular disease endpoints. Determination of promotional tone was based on the assessment by each reader of whether the article appeared to promote hormone therapy. Analysis of inter-rater consistency found moderate agreement for scientific accuracy (κ = 0.57) and substantial agreement for promotional tone (κ = 0.65). After discussion, readers found 86% of the articles to be scientifically accurate and 64% to be promotional in tone. Themes that were common in articles considered promotional included attacks on the methodology of the WHI, arguments that clinical trial results should not guide treatment for individuals, and arguments that observational studies are as good as or better than randomized clinical trials for guiding clinical decisions. The promotional articles we identified also implied that the risks associated with hormone therapy have been exaggerated and that the benefits of hormone therapy have been or will be proven. Of the ten authors studied, eight were found to have declared payment for speaking or consulting on behalf of menopausal hormone manufacturers or for research support (seven of these eight were speakers or consultants). Thirty of 32 articles (90%) evaluated as promoting hormone therapy were authored by those with potential financial conflicts of interest, compared to 11 of 18 articles (61%) by those without such conflicts (p = 0.0025). Articles promoting the use of menopausal hormone therapy were 2.41 times (95% confidence interval 1.49–4.93) as likely to have been authored by authors with conflicts of interest as by authors without conflicts of interest. In articles from three authors with conflicts of interest some of the same text was repeated word-for-word in different articles.
There may be a connection between receiving industry funding for speaking, consulting, or research and the publication of promotional opinion pieces on menopausal hormone therapy.
Please see later in the article for the Editors' Summary
Editors' Summary
Over the past three decades, menopausal hormones have been heavily promoted for preventing disease in women. However, the Women's Health Initiative (WHI) study—which enrolled more than 26,000 women in the US and which was published in 2004—found that estrogen-progestin and estrogen-only formulations (often prescribed to women around the age of menopause) increased the risk of stroke, deep vein thrombosis, dementia, and incontinence. Furthermore, this study found that the estrogen-progestin therapy increased rates of breast cancer. In fact, the estrogen-progestin arm of the WHI study was stopped in 2002 due to harmful findings, and the estrogen-only arm was stopped in 2004, also because of harmful findings. In addition, the study also found that neither therapy reduced cardiovascular risk or markedly benefited health-related quality of life measures.
Despite these results, two years after the results of WHI study were published, a survey of over 700 practicing gynecologists—the specialists who prescribe the majority of menopausal hormone therapies—in the US found that almost half did not find the findings of the WHI study convincing and that 48% disagreed with the decision to stop the trial early. Furthermore, follow-up surveys found similar results.
Why Was This Study Done?
It is unclear why gynecologists and other physicians continue to prescribe menopausal hormone therapies despite the results of the WHI. Some academics argue that published industry-funded reviews and commentaries may be designed to convey specific, but subtle, marketing messages and several academic analyses have used internal industry documents disclosed in litigation cases. So this study was conducted to investigate whether hormone therapy–promoting tone could be identified in narrative review articles and if so, whether these articles were more likely to have been authored by people who had accepted funding from hormone manufacturers.
What Did the Researchers Do and Find?
The researchers conducted a comprehensive literature search that identified 340 relevant articles published between July 2002 and June 2006—the four years following the cessation of the estrogen-progestin arm of the women's health initiative study. Ten authors had published four to six articles, 47 authored two or three articles, and 371 authored one article each. The researchers focused on authors who had published four or more articles in the four-year period under study and, after author names and affiliations were removed, 50 articles were evaluated by three readers for scientific accuracy and for tone. After individually analyzing a batch of articles, the readers met to provide their initial assessments, to discuss them, and to reach consensus on tone and scientific accuracy. Then after the papers were evaluated, each author was identified and the researchers searched for authors' potential financial conflicts of interest, defined as publicly disclosed information that the authors had received payment for research, speaking, or consulting on behalf of a manufacturer of menopausal hormone therapy.
Common themes in the 50 articles included arguments that clinical trial results should not guide treatment for individuals and suggestions that the risks associated with hormone therapy have been exaggerated and that the benefits of hormone therapy have been or will be proven. Furthermore, of the ten authors studied, eight were found to have received payment for research, speaking or consulting on behalf of menopause hormone manufacturers, and 30 of 32 articles evaluated as promoting hormone therapy were authored by those with potential financial conflicts of interest. Articles promoting the use of menopausal hormone therapy were more than twice as likely to have been written by authors with conflicts of interest as by authors without conflicts of interest. Furthermore, Three authors who were identified as having financial conflicts of interest were authors on articles where sections of their previously published articles were repeated word-for-word without citation.
What Do These Findings Mean?
The findings of this study suggest that there may be a link between receiving industry funding for speaking, consulting, or research and the publication of apparently promotional opinion pieces on menopausal hormone therapy. Furthermore, such publications may encourage physicians to continue prescribing these therapies to women of menopausal age. Therefore, physicians and other health care providers should interpret the content of review articles with caution. In addition, medical journals should follow the International Committee of Medical Journal Editors Uniform Requirements for Manuscripts, which require that all authors submit signed statements of their participation in authorship and full disclosure of any conflicts of interest.
Additional Information
Please access these Web sites via the online version of this summary at
The US National Heart, Lung, and Blood Institute has more information on the Womens Health Initiative
The US National Institutes of Health provide more information about the effects of menopausal hormone replacement therapy
The Office of Women's Health, U.S. Department of Health and Human Services provides information on menopausal hormone therapy
The International Committee of Medical Journal Editors Uniform Requirements for Manuscripts presents Uniform Requirements for Manuscripts published in biomedical journals
The National Womens Health Network, a consumer advocacy group that takes no industry money, has factsheets and articles about menopausal hormone therapy
PharmedOut, a Georgetown University Medical Center project, has many resources on pharmaceutical marketing practices
PMCID: PMC3058057  PMID: 21423581
11.  Effect of dietary intervention on serum lignan levels in pregnant women - a controlled trial 
Reproductive Health  2010;7:26.
Mother's diet during pregnancy is important, since plant lignans and their metabolites, converted by the intestinal microflora to enterolignans, are proposed to possess multiple health benefits. Aim of our study was to investigate whether a dietary intervention affects lignan concentrations in the serum of pregnant women.
A controlled dietary intervention trial including 105 first-time pregnant women was conducted in three intervention and three control maternity health clinics. The intervention included individual counseling on diet and on physical activity, while the controls received conventional care. Blood samples were collected on gestation weeks 8-9 (baseline) and 36-37 (end of intervention). The serum levels of the plant lignans 7-hydroxymatairesinol, secoisolariciresinol, matairesinol, lariciresinol, cyclolariciresinol, and pinoresinol, and of the enterolignans 7-hydroxyenterolactone, enterodiol, and enterolactone, were measured using a validated method.
The baseline levels of enterolactone, enterodiol and the sum of lignans were higher in the control group, whereas at the end of the trial their levels were higher in the intervention group. The adjusted mean differences between the baseline and end of the intervention for enterolactone and the total lignan intake were 1.6 ng/ml (p = 0.018, 95% CI 1.1-2.3) and 1.4 ng/mg (p = 0.08, 95% CI 1.0-1.9) higher in the intervention group than in the controls. Further adjustment for dietary components did not change these associations.
The dietary intervention was successful in increasing the intake of lignan-rich food products, the fiber consumption and consequently the plasma levels of lignans in pregnant women.
Trial registration
PMCID: PMC2958873  PMID: 20932282
12.  Metabolic alteration of urinary steroids in pre- and post-menopausal women, and men with papillary thyroid carcinoma 
BMC Cancer  2011;11:342.
To evaluate the metabolic changes in urinary steroids in pre- and post-menopausal women and men with papillary thyroid carcinoma (PTC).
Quantitative steroid profiling combined with gas chromatography-mass spectrometry was used to measure the urinary concentrations of 84 steroids in both pre- (n = 21, age: 36.95 ± 7.19 yr) and post-menopausal female (n = 19, age: 52.79 ± 7.66 yr), and male (n = 16, age: 41.88 ± 8.48 yr) patients with PTC. After comparing the quantitative data of the patients with their corresponding controls (pre-menopause women: n = 24, age: 33.21 ± 10.48 yr, post-menopause women: n = 16, age: 49.67 ± 8.94 yr, male: n = 20, age: 42.75 ± 4.22 yr), the levels of steroids in the patients were normalized to the mean concentration of the controls to exclude gender and menopausal variations.
Many urinary steroids were up-regulated in all PTC patients compared to the controls. Among them, the levels of three active androgens, androstenedione, androstenediol and 16α-hydroxy DHEA, were significantly higher in the pre-menopausal women and men with PTC. The corticoid levels were increased slightly in the PTC men, while progestins were not altered in the post-menopausal PTC women. Estrogens were up-regulated in all PTC patients but 2-hydroxyestrone and 2-hydroxy-17β-estradiol were remarkably changed in both pre-menopausal women and men with PTC. For both menopausal and gender differences, the 2-hydroxylation, 4-hydroxylation, 2-methoxylation, and 4-methoxylation of estrogens and 16α-hydroxylation of DHEA were differentiated between pre- and post-menopausal PTC women (P < 0.001). In particular, the metabolic ratio of 2-hydroxyestrone to 2-hydroxy-17β-estradiol, which could reveal the enzyme activity of 17β-hydroxysteroid dehydrogenase, showed gender differences in PTC patients (P < 1 × 10-7).
These results are expected be helpful for better understanding the pathogenic differences in PTC according to gender and menopausal conditions.
PMCID: PMC3199870  PMID: 21824401
Steroids; Thyroid cancer; Menopause; Gender difference; GC-MS
13.  Risk Prediction for Breast, Endometrial, and Ovarian Cancer in White Women Aged 50 y or Older: Derivation and Validation from Population-Based Cohort Studies 
PLoS Medicine  2013;10(7):e1001492.
Ruth Pfeiffer and colleagues describe models to calculate absolute risks for breast, endometrial, and ovarian cancers for white, non-Hispanic women over 50 years old using easily obtainable risk factors.
Please see later in the article for the Editors' Summary
Breast, endometrial, and ovarian cancers share some hormonal and epidemiologic risk factors. While several models predict absolute risk of breast cancer, there are few models for ovarian cancer in the general population, and none for endometrial cancer.
Methods and Findings
Using data on white, non-Hispanic women aged 50+ y from two large population-based cohorts (the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial [PLCO] and the National Institutes of Health–AARP Diet and Health Study [NIH-AARP]), we estimated relative and attributable risks and combined them with age-specific US-population incidence and competing mortality rates. All models included parity. The breast cancer model additionally included estrogen and progestin menopausal hormone therapy (MHT) use, other MHT use, age at first live birth, menopausal status, age at menopause, family history of breast or ovarian cancer, benign breast disease/biopsies, alcohol consumption, and body mass index (BMI); the endometrial model included menopausal status, age at menopause, BMI, smoking, oral contraceptive use, MHT use, and an interaction term between BMI and MHT use; the ovarian model included oral contraceptive use, MHT use, and family history or breast or ovarian cancer. In independent validation data (Nurses' Health Study cohort) the breast and ovarian cancer models were well calibrated; expected to observed cancer ratios were 1.00 (95% confidence interval [CI]: 0.96–1.04) for breast cancer and 1.08 (95% CI: 0.97–1.19) for ovarian cancer. The number of endometrial cancers was significantly overestimated, expected/observed = 1.20 (95% CI: 1.11–1.29). The areas under the receiver operating characteristic curves (AUCs; discriminatory power) were 0.58 (95% CI: 0.57–0.59), 0.59 (95% CI: 0.56–0.63), and 0.68 (95% CI: 0.66–0.70) for the breast, ovarian, and endometrial models, respectively.
These models predict absolute risks for breast, endometrial, and ovarian cancers from easily obtainable risk factors and may assist in clinical decision-making. Limitations are the modest discriminatory ability of the breast and ovarian models and that these models may not generalize to women of other races.
Please see later in the article for the Editors' Summary
Editors' Summary
In 2008, just three types of cancer accounted for 10% of global cancer-related deaths. That year, about 460,000 women died from breast cancer (the most frequently diagnosed cancer among women and the fifth most common cause of cancer-related death). Another 140,000 women died from ovarian cancer, and 74,000 died from endometrial (womb) cancer (the 14th and 20th most common causes of cancer-related death, respectively). Although these three cancers originate in different tissues, they nevertheless share many risk factors. For example, current age, age at menarche (first period), and parity (the number of children a woman has had) are all strongly associated with breast, ovarian, and endometrial cancer risk. Because these cancers share many hormonal and epidemiological risk factors, a woman with a high breast cancer risk is also likely to have an above-average risk of developing ovarian or endometrial cancer.
Why Was This Study Done?
Several statistical models (for example, the Breast Cancer Risk Assessment Tool) have been developed that estimate a woman's absolute risk (probability) of developing breast cancer over the next few years or over her lifetime. Absolute risk prediction models are useful in the design of cancer prevention trials and can also help women make informed decisions about cancer prevention and treatment options. For example, a woman at high risk of breast cancer might decide to take tamoxifen for breast cancer prevention, but ideally she needs to know her absolute endometrial cancer risk before doing so because tamoxifen increases the risk of this cancer. Similarly, knowledge of her ovarian cancer risk might influence a woman's decision regarding prophylactic removal of her ovaries to reduce her breast cancer risk. There are few absolute risk prediction models for ovarian cancer, and none for endometrial cancer, so here the researchers develop models to predict the risk of these cancers and of breast cancer.
What Did the Researchers Do and Find?
Absolute risk prediction models are constructed by combining estimates for risk factors from cohorts with population-based incidence rates from cancer registries. Models are validated in an independent cohort by testing their ability to identify people with the disease in an independent cohort and their ability to predict the observed numbers of incident cases. The researchers used data on white, non-Hispanic women aged 50 years or older that were collected during two large prospective US cohort studies of cancer screening and of diet and health, and US cancer incidence and mortality rates provided by the Surveillance, Epidemiology, and End Results Program to build their models. The models all included parity as a risk factor, as well as other factors. The model for endometrial cancer, for example, also included menopausal status, age at menopause, body mass index (an indicator of the amount of body fat), oral contraceptive use, menopausal hormone therapy use, and an interaction term between menopausal hormone therapy use and body mass index. Individual women's risk for endometrial cancer calculated using this model ranged from 1.22% to 17.8% over the next 20 years depending on their exposure to various risk factors. Validation of the models using data from the US Nurses' Health Study indicated that the endometrial cancer model overestimated the risk of endometrial cancer but that the breast and ovarian cancer models were well calibrated—the predicted and observed risks for these cancers in the validation cohort agreed closely. Finally, the discriminatory power of the models (a measure of how well a model separates people who have a disease from people who do not have the disease) was modest for the breast and ovarian cancer models but somewhat better for the endometrial cancer model.
What Do These Findings Mean?
These findings show that breast, ovarian, and endometrial cancer can all be predicted using information on known risk factors for these cancers that is easily obtainable. Because these models were constructed and validated using data from white, non-Hispanic women aged 50 years or older, they may not accurately predict absolute risk for these cancers for women of other races or ethnicities. Moreover, the modest discriminatory power of the breast and ovarian cancer models means they cannot be used to decide which women should be routinely screened for these cancers. Importantly, however, these well-calibrated models should provide realistic information about an individual's risk of developing breast, ovarian, or endometrial cancer that can be used in clinical decision-making and that may assist in the identification of potential participants for research studies.
Additional Information
Please access these websites via the online version of this summary at
This study is further discussed in a PLOS Medicine Perspective by Lars Holmberg and Andrew Vickers
The US National Cancer Institute provides comprehensive information about cancer (in English and Spanish), including detailed information about breast cancer, ovarian cancer, and endometrial cancer;
Information on the Breast Cancer Risk Assessment Tool, the Surveillance, Epidemiology, and End Results Program, and on the prospective cohort study of screening and the diet and health study that provided the data used to build the models is also available on the NCI site
Cancer Research UK, a not-for-profit organization, provides information about cancer, including detailed information on breast cancer, ovarian cancer, and endometrial cancer
The UK National Health Service Choices website has information and personal stories about breast cancer, ovarian cancer, and endometrial cancer; the not-for-profit organization Healthtalkonline also provides personal stories about dealing with breast cancer and ovarian cancer
PMCID: PMC3728034  PMID: 23935463
14.  Effects of pesticides on the ratio of 16 alpha/2-hydroxyestrone: a biologic marker of breast cancer risk. 
Environmental Health Perspectives  1995;103(Suppl 7):147-150.
Xenobiotic estrogens are external compounds with estrogenic activity that may thereby affect the risk of breast cancer. This paper describes a mechanism by which xeno-estrogens may affect the development of breast cancer. Estradiol metabolism proceeds by hydroxylation at one of two mutually exclusive sites at C-2 and C-16 alpha. The catechol pathway yields the weakly estrogenic 2-hydroxyestrone (2-OHE1), which inhibits breast cell proliferation. In contrast, the alternative pathway yields the genotoxic 16 alpha-hydroxyestrone (16 alpha-OHE1), which enhances breast cell growth, increases unscheduled DNA synthesis, and oncogene and virus expression, and increases anchorage-independent growth. Using a radiometric assay that measures the relative formation of 16 alpha-OHE1 versus 2-OHE1 from specifically tritiated estradiol in (ER+) MCF-7 cells, we compared the ratio of 16 alpha-OHE1/2-OHE1 observed after treatment with the known rodent carcinogen 7,12-dimethylbenz[a]anthracene (DMBA) with the ratios after treatment with DDT, atrazine, gamma-benzene hexachloride, kepone, coplanar PCBs, endosulfans I and II, linoleic and eicosapentenoic acids, and indole-3-carbinol (I3C). These pesticides significantly increase the ratio of 16 alpha-OHE1/2-OHE1 metabolites to values comparable to or greater than those observed after DMBA. In contrast, the antitumor agent I3C increased 2-OHE1 formation and yielded ratios that are 1/3 of those found in unexposed control cells and 1/10th of those found in DMBA-treated cells. Thus the ratio of 16 alpha-OHE1/2-OHE1 may provide a marker for the risk of breast cancer. Assays of this ratio, which can be measured in spot urines, may prove useful for a variety of in vitro and in vivo studies bearing on breast cancer risk.
PMCID: PMC1518879  PMID: 8593862
15.  Vitamin K Supplementation in Postmenopausal Women with Osteopenia (ECKO Trial): A Randomized Controlled Trial 
PLoS Medicine  2008;5(10):1-12.
Vitamin K has been widely promoted as a supplement for decreasing bone loss in postmenopausal women, but the long-term benefits and potential harms are unknown. This study was conducted to determine whether daily high-dose vitamin K1 supplementation safely reduces bone loss, bone turnover, and fractures.
Methods and Findings
This single-center study was designed as a 2-y randomized, placebo-controlled, double-blind trial, extended for earlier participants for up to an additional 2 y because of interest in long-term safety and fractures. A total of 440 postmenopausal women with osteopenia were randomized to either 5 mg of vitamin K1 or placebo daily. Primary outcomes were changes in BMD at the lumbar spine and total hip at 2 y. Secondary outcomes included changes in BMD at other sites and other time points, bone turnover markers, height, fractures, adverse effects, and health-related quality of life. This study has a power of 90% to detect 3% differences in BMD between the two groups. The women in this study were vitamin D replete, with a mean serum 25-hydroxyvitamin D level of 77 nmol/l at baseline. Over 2 y, BMD decreased by −1.28% and −1.22% (p = 0.84) (difference of −0.06%; 95% confidence interval [CI] −0.67% to 0.54%) at the lumbar spine and −0.69% and −0.88% (p = 0.51) (difference of 0.19%; 95% CI −0.37% to 0.75%) at the total hip in the vitamin K and placebo groups, respectively. There were no significant differences in changes in BMD at any site between the two groups over the 2- to 4-y period. Daily vitamin K1 supplementation increased serum vitamin K1 levels by 10-fold, and decreased the percentage of undercarboxylated osteocalcin and total osteocalcin levels (bone formation marker). However, C-telopeptide levels (bone resorption marker) were not significantly different between the two groups. Fewer women in the vitamin K group had clinical fractures (nine versus 20, p = 0.04) and fewer had cancers (three versus 12, p = 0.02). Vitamin K supplements were well-tolerated over the 4-y period. There were no significant differences in adverse effects or health-related quality of life between the two groups. The study was not powered to examine fractures or cancers, and their numbers were small.
Daily 5 mg of vitamin K1 supplementation for 2 to 4 y does not protect against age-related decline in BMD, but may protect against fractures and cancers in postmenopausal women with osteopenia. More studies are needed to further examine the effect of vitamin K on fractures and cancers.
Trial registration: (#NCT00150969) and Current Controlled Trials (#ISRCTN61708241)
Angela Cheung and colleagues investigate whether vitamin K1 can prevent bone loss among postmenopausal women with osteopenia.
Editors' Summary
Osteoporosis is a bone disease in which the bones gradually become less dense and more likely to break. In the US, 10 million people have osteoporosis and 18 million have osteopenia, a milder condition that precedes osteoporosis. In both conditions, insufficient new bone is made and/or too much old bone is absorbed. Although bone appears solid and unchanging, very little bone in the human body is more than 10 y old. Old bone is continually absorbed and new bone built using calcium, phosphorous, and proteins. Because the sex hormones control calcium and phosphorous deposition in the bones and thus bone strength, the leading cause of osteoporosis in women is reduced estrogen levels after menopause. In men, an age-related decline in testosterone levels can cause osteoporosis. Most people discover they have osteoporosis only when they break a bone, but the condition can be diagnosed and monitored using bone mineral density (BMD) scans. Treatments can slow down or reverse bone loss (antiresorptive therapies) and some (bone formation therapies) can even make bone and build bone tissue.
Why Was This Study Done?
Although regular exercise and a healthy diet can help to keep bones strong, other ways of preventing osteoporosis are badly needed. Recently, the lay media has promoted vitamin K supplements as a way to reduce bone loss in postmenopausal women. Vitamin K (which is found mainly in leafy green vegetables) is required for a chemical modification of proteins called carboxylation. This modification is essential for the activity of three bone-building proteins. In addition, there is some evidence that low bone density and fractures are associated with a low vitamin K intake. However, little is known about the long-term benefits or harms of vitamin K supplements. In this study, the researchers investigate whether a high-dose daily vitamin K supplement can safely reduce bone loss, bone turnover, and fractures in postmenopausal women with osteopenia in a randomized controlled trial called the “Evaluation of the Clinical Use of Vitamin K Supplementation in Post-Menopausal Women With Osteopenia” (ECKO) trial.
What Did the Researchers Do and Find?
In the study, 440 postmenopausal women with osteopenia were randomized to receive 5mg of vitamin K1 (the type of vitamin K in North American food; the recommended daily adult intake of vitamin K1 is about 0.1 mg) or an inactive tablet (placebo) daily for 2 y; 261 of the women continued their treatment for 2 y to gather information about the long-term effects of vitamin K1 supplementation. All the women had regular bone density scans of their lower back and hips and were examined for fractures and for changes in bone turnover. After 2 y and after 4 y, lower back and hip bone density measurements had decreased by similar amounts in both treatment groups. The women who took vitamin K1 had 10-fold higher amounts of vitamin K1 in their blood than the women who took placebo and lower amounts of a bone formation marker; the levels of a bone resorption marker were similar in both groups. Over the 4-y period, fewer women in the vitamin K group had fractures (nine versus 20 women in the placebo group), and fewer had cancer (three versus 12). Finally, vitamin K supplementation was well tolerated over the 4-y period and adverse health effects were similar in the two treatment groups.
What Do These Findings Mean?
These findings indicate that a high daily dose of vitamin K1 provides no protection against the age-related decline in bone density in postmenopausal women with osteopenia, but that vitamin K1 supplementation may protect against fractures and cancers in these women. The apparent contradiction between the effects of vitamin K1 on bone density and on fractures could mean that vitamin K1 supplements strengthen bone by changing factors other than bone density, e.g., by changing its fine structure rather than making it denser. However, because so few study participants had fractures, the difference in the fracture rate between the two treatment groups might have occurred by chance. Larger studies are therefore needed to examine the effect of vitamin K1 on fractures (and on cancer) and, until these are done, high-dose vitamin K1 supplementation should not be recommended for the prevention of osteoporosis.
Additional Information.
Please access these Web sites via the online version of this summary at
The US National Institute of Arthritis and Musculoskeletal and Skin Diseases provides detailed information about osteoporosis (in English and Spanish) and links to other resources, including an interactive web tool called Check Up On Your Bones
MedlinePlus provides links to additional information about osteoporosis (in English and Spanish)
The MedlinePlus Encyclopedia has a page about vitamin K
The UK Food Standards Agency provides information about vitamin K
Full details about the ECKO trial are available on the Web site
The Canadian Task Force for Preventive Health Care provides recommendations on the prevention of osteoporosis and osteoporotic fractures in postmenopausal women
Osteoporosis Canada provides information on current topics related to osteoporosis
PMCID: PMC2566998  PMID: 18922041
16.  Pharmacokinetics and Bioavailability of Plant Lignan 7-Hydroxymatairesinol and Effects on Serum Enterolactone and Clinical Symptoms in Postmenopausal Women: A Single-Blinded, Parallel, Dose-Comparison Study 
7-Hydroxymaitairesinol (7-HMR) is a naturally occurring plant lignan found in whole grains and the Norway spruce (Piciea abies). The purpose of this study was to evaluate the bioavailability of a proprietary 7-HMR product (HMRlignan, Linnea SA, Locarno, Switzerland) through measurement of lignan metabolites and metabolic precursors.
A single-blind, parallel, pharmacokinetic and dose-comparison study was conducted on 22 post-menopausal females not receiving hormone replacement therapy. Subjects were enrolled in either a 36 mg/d (low-dose) or 72 mg/d dose (high-dose) regimen for 8 weeks. Primary measured outcomes included plasma levels of 7-HMR and enterolactone (ENL), and single-dose pharmacokinetic analysis was performed on a subset of subjects in the low-dose group. Safety data and adverse event reports were collected as well as data on hot flash frequency and severity.
Pharmacokinetic studies demonstrated 7-HMR Cmax = 757.08 ng/ml at 1 hour and ENL Cmax = 4.8 ng/ml at 24 hours. From baseline to week 8, plasma 7-HMR levels increased by 191% in the low-dose group (p < 0.01) and by 1238% in the high-dose group (p < 0.05). Plasma ENL levels consistently increased as much as 157% from baseline in the low-dose group and 137% in the high-dose group. Additionally, the mean number of weekly hot flashes decreased by 50%, from 28.0/week to 14.3/week (p < 0.05) in the high-dose group. No significant safety issues were identified in this study.
The results demonstrate that HMRlignan is quickly absorbed into the plasma and is metabolized to ENL in healthy postmenopausal women. Clinically, the data demonstrate a statistically significant improvement in hot flash frequency. Doses up to 72 mg/d HMRlignan for 8 weeks were safe and well tolerated in this population.
PMCID: PMC3877914  PMID: 24606716
lignans; 7-Hydroxymatairesinol; enterolactone; pharmacokinetics; bioavailability; hot flashes; postmenopausal women
17.  Incorporating bazedoxifene/conjugated estrogens into the current paradigm of menopausal therapy 
Many women experience bothersome vasomotor and vaginal symptoms during the menopausal transition. Decreasing levels of estrogens during menopause are also associated with reduced bone density and an increased risk of osteoporosis. Combined estrogen/progestin therapy (hormone therapy) effectively treats menopausal symptoms and prevents bone loss, but has been associated with some safety and tolerability concerns. A novel menopausal therapy is the tissue selective estrogen complex, which pairs a selective estrogen receptor modulator with one or more estrogens. In preclinical studies, the tissue selective estrogen complex partnering bazedoxifene (BZA) with conjugated estrogens (CE) antagonized stimulation of breast and endometrial tissue, reduced vasomotor instability, and preserved bone mass in rat and mouse models. The specific attributes seen with BZA/CE were different from those observed with other selective estrogen receptor modulator/estrogen pairings. BZA/CE has undergone clinical evaluation in the Phase III Selective estrogens, Menopause, And Response to Therapy (SMART) trials in postmenopausal women with an intact uterus. Of the various doses of BZA/CE evaluated, BZA 20 mg/CE 0.45 mg and 0.625 mg were associated with a low incidence of endometrial hyperplasia (<1%) similar to placebo, and showed significant improvements in hot flushes and vulvar/vaginal symptoms and increases in bone mineral density. BZA 20 mg/CE 0.45 mg and 0.625 mg were associated with a low incidence of breast-related adverse events and demonstrated no difference from placebo in age-related changes in mammographic breast density. Both BZA/ CE doses showed a favorable tolerability profile, with no increases in uterine bleeding or breast tenderness, and had positive effects on metabolic parameters and quality of life. BZA/CE may be a promising alternative to hormone therapy for the treatment of menopausal symptoms and prevention of osteoporosis in nonhysterectomized postmenopausal women.
PMCID: PMC3325004  PMID: 22505832
tissue selective estrogen complex; bazedoxifene; conjugated estrogens; menopause; osteoporosis; vasomotor symptoms
18.  Ruminal Prevotella spp. May Play an Important Role in the Conversion of Plant Lignans into Human Health Beneficial Antioxidants 
PLoS ONE  2014;9(4):e87949.
Secoisolariciresinol diglucoside (SDG), the most abundant lignan in flaxseed, is metabolized by the ruminal microbiota into enterolignans, which are strong antioxidants. Enterolactone (EL), the main mammalian enterolignan produced in the rumen, is transferred into physiological fluids, with potentially human health benefits with respect to menopausal symptoms, hormone-dependent cancers, cardiovascular diseases, osteoporosis and diabetes. However, no information exists to our knowledge on bacterial taxa that play a role in converting plant lignans into EL in ruminants. In order to investigate this, eight rumen cannulated cows were used in a double 4×4 Latin square design and fed with four treatments: control with no flax meal (FM), or 5%, 10% and 15% FM (on a dry matter basis). Concentration of EL in the rumen increased linearly with increasing FM inclusion. Total rumen bacterial 16S rRNA concentration obtained using Q-PCR did not differ among treatments. PCR-T-RFLP based dendrograms revealed no global clustering based on diet indicating between animal variation. PCR-DGGE showed a clustering by diet effect within four cows that had similar basal ruminal microbiota. DNA extracted from bands present following feeding 15% FM and absent with no FM supplementation were sequenced and it showed that many genera, in particular Prevotella spp., contributed to the metabolism of lignans. A subsequent in vitro study using selected pure cultures of ruminal bacteria incubated with SDG indicated that 11 ruminal bacteria were able to convert SDG into secoisolariciresinol (SECO), with Prevotella spp. being the main converters. These data suggest that Prevotella spp. is one genus playing an important role in the conversion of plant lignans to human health beneficial antioxidants in the rumen.
PMCID: PMC3977842  PMID: 24709940
19.  Reduction in Ki-67 in Benign Breast Tissue of High Risk Women with the Lignan Secoisolariciresinol Diglycoside (SDG) 
Preclinical and correlative studies suggest reduced breast cancer with higher lignan intake or blood levels. We conducted a pilot study of modulation of risk biomarkers for breast cancer in premenopausal women after administration of the plant lignan secoisolariciresinol given as the diglycoside (SDG). Eligibility criteria included regular menstrual cycles, no oral contraceptives, a greater than 3-fold increase in 5 year risk, and baseline Ki-67 ≥2% in areas of hyperplasia in breast tissue sampled by random periareolar fine needle aspiration (RPFNA) during the follicular phase of the menstrual cycle. SDG 50 mg daily was given for 12 months, followed by repeat RPFNA. The primary endpoint was change in Ki-67. Secondary endpoints included change in cytomorphology, mammographic breast density, serum bioavailable estradiol, and testosterone IGF-I and IGFBP-3, and plasma lignan levels. Forty-five of 49 eligible women completed the study with excellent compliance (median = 96%) and few serious side effects (4% grade 3). Median plasma enterolactone increased ~ 9-fold, and total lignans 16 fold. Thirty-six (80%) of the 45 evaluable subjects demonstrated a decrease in Ki-67, from a median of 4% (range 2–16.8 %) to 2% (range 0–15.2%) (p<0.001 by Wilcoxon signed rank test). A decrease from baseline in the proportion of women with atypical cytology (p=0.035) was also observed. Based on favorable risk biomarker modulation and lack of adverse events, we are initiating a randomized trial of SDG vs. placebo in premenopausal women.
PMCID: PMC2955777  PMID: 20724470
20.  Assessment of Information to Substantiate a Health Claim on the Prevention of Prostate Cancer by Lignans 
Nutrients  2010;2(2):99-115.
Lignans and their in vivo metabolites, especially enterolactone (ENL), have attracted substantial interest as potential chemopreventive agents for prostate cancer. Preclinical and clinical interventions performed with lignan-rich flaxseed that use surrogate biomarkers as endpoints suggest that lignans may attenuate prostate carcinogenesis in individuals with increased risk or with diagnosed cancer. No unequivocal prostate cancer risk reduction has been found for lignans in epidemiological studies, suggesting that lignan concentrations found in populations consuming a regular non-supplemented diet are not chemopreventive in prostate cancer. Presumably, the main obstacles in assessing the efficacy of food lignans is limited knowledge of the serum and tissue lignan concentrations required for the putative prevention. Further clinical studies performed with the purified compounds are required to substantiate a health claim.
PMCID: PMC3257165  PMID: 22254011
lignan; phytoestrogen; diet; prostate cancer; health claim; surrogate biomarker
21.  Hip Fracture Incidence in Relation to Age, Menopausal Status, and Age at Menopause: Prospective Analysis 
PLoS Medicine  2009;6(11):e1000181.
Using data from the UK Million Women Study, Emily Banks and colleagues investigate the relationships between the incidence of hip fracture and a woman's age, menopausal status, and age at menopause.
Bone mineral density is known to decrease rapidly after the menopause. There is limited evidence about the separate contributions of a woman's age, menopausal status and age at menopause to the incidence of hip fracture.
Methods and Findings
Over one million middle-aged women joined the UK Million Women Study in 1996–2001 providing information on their menopausal status, age at menopause, and other factors, which was updated, where possible, 3 y later. All women were registered with the UK National Health Service (NHS) and were routinely linked to information on cause-specific admissions to NHS hospitals. 561,609 women who had never used hormone replacement therapy and who provided complete information on menopausal variables (at baseline 25% were pre/perimenopausal and 75% postmenopausal) were followed up for a total of 3.4 million woman-years (an average 6.2 y per woman). During follow-up 1,676 (0.3%) were admitted to hospital with a first incident hip fracture. Among women aged 50–54 y the relative risk (RR) of hip fracture risk was significantly higher in postmenopausal than premenopausal women (adjusted RR 2.22, 95% confidence interval [CI] 1.22–4.04; p = 0.009); there were too few premenopausal women aged 55 y and over for valid comparisons. Among postmenopausal women, hip fracture incidence increased steeply with age (p<0.001), with rates being about seven times higher at age 70–74 y than at 50–54 y (incidence rates of 0.82 versus 0.11 per 100 women over 5 y). Among postmenopausal women of a given age there was no significant difference in hip fracture incidence between women whose menopause was due to bilateral oophorectomy compared to a natural menopause (adjusted RR 1.20, 95% CI 0.94–1.55; p = 0.15), and age at menopause had little, if any, effect on hip fracture incidence.
At around the time of the menopause, hip fracture incidence is about twice as high in postmenopausal than in premenopausal women, but this effect is short lived. Among postmenopausal women, age is by far the main determinant of hip fracture incidence and, for women of a given age, their age at menopause has, at most, a weak additional effect.
Please see later in the article for the Editors' Summary
Editors' Summary
Anyone can break a hip but most hip fractures occur in elderly people. As people age, their bones gradually lose minerals and become less dense, which weakens the bones and makes them more susceptible to fracture. Because women lose bone density faster than men as they age and because women constitute the majority of the elderly, three-quarters of hip fractures occur in women. Hip fractures can cause long-term health problems and premature death. Thus, although surgical repair of a broken hip usually only requires a hospital stay of about a week, a quarter of elderly people who were living independently before their fracture have to stay in a nursing home for at least a year after their injury and a fifth of elderly people who break a hip die within the year. Most hip fractures are caused by falls. Regular exercise to improve strength and balance combined with review of medicines (to reduce side effects and interactions), regular eye examinations, and the removal of fall hazards from the home can help to prevent hip fractures in elderly people.
Why Was This Study Done?
Bone density decreases very rapidly in women immediately after menopause—the time when menstruation permanently stops—and then continues to decrease more slowly with age. Most women have their menopause in their early 50s but menopause can occur in younger women. Early menopause is thought to be a risk factor for osteoporosis (thinning of the bones) and fractures later in life but little is known about how menopause influences hip fracture risk as women age. In this prospective study (a type of study in which a group of people is followed for several years to see whether they develop a particular condition), the researchers investigate the incidence of hip fractures in relation to age, menopausal status, and age at menopause among the participants of the Million Women Study. This study, which recruited 1.3 million women aged 50–64 years who attended UK breast cancer screening clinics between 1996 and 2001, has been investigating how reproductive and lifestyle factors affect women's health.
What Did the Researchers Do and Find?
At enrollment and three years later, the study participants provided information about their menopausal status and other health and lifestyle factors likely to affect their fracture risk. From these data, the researchers identified more than half a million women who had never used hormone replacement therapy (which reduces fracture risk) and who had given complete information about their menopausal status. They then looked for statistical associations between the occurrence of a first hip fracture in these women over the next few years and their age, menopausal status, and age at menopause. Among women aged 50–54 years, postmenopausal women were twice as likely to have a hip fracture as premenopausal women. Among postmenopausal women, the incidence of hip fractures increased steeply with age and was seven times higher in 70–74-year olds than in 50–54-year olds. Women who had their menopause before age 45 had a slightly increased risk of hip fracture but any effect of age at menopause on the risk of hip fracture was small compared to the effect of age itself, and the slightly increased risk may have been due to other factors that could not be fully accounted for in the analysis.
What Do These Findings Mean?
These findings indicate that around the time of menopause, although hip fractures are rare, the risk of a fracture in postmenopausal women is twice that in premenopausal women. The findings also show that among postmenopausal women, age is the major determinant of hip fracture risk and that for women of a given age, their age at menopause has little effect on hip fracture risk. Women attending breast cancer screening clinics and completing questionnaires about their health may not be representative of the general population. Furthermore, these findings rely on women self-reporting their menopausal status accurately. Nevertheless, the results of this study suggest that clinicians advising women about hip fracture prevention should probably base their advice on the woman's age and on age-related factors such as frailty rather than on factors related to menopause. Clinicians can also now reassure elderly women who had an early menopause that their risk of hip fracture is unlikely to be higher than that of similar women who had a later menopause.
Additional Information
Please access these Web sites via the online version of this summary at
The American Academy of Orthopaedic Surgeons has detailed information about hip fractures
The US National Institute of Arthritis and Muscoloskeletal and Skin Diseases has an interactive feature called “Check up on your bones and provides detailed information about osteoporosis, including advice on fall prevention
The US Centers for Disease Control and Prevention has a fact sheet about hip fractures among older adults
MedlinePlus has links to resources about hip fracture, osteoporosis, and menopause (in English and Spanish)
More information on the Million Women Study is available
PMCID: PMC2766835  PMID: 19901981
22.  Impact of Sex Hormone Metabolism on the Vascular Effects of Menopausal Hormone Therapy in Cardiovascular Disease 
Current drug metabolism  2010;11(8):693-714.
Epidemiological studies have shown that cardiovascular disease (CVD) is less common in pre-menopausal women (Pre-MW) compared to men of the same age or post-menopausal women (Post-MW), suggesting cardiovascular benefits of estrogen. Estrogen receptors (ERs) have been identified in the vasculature, and experimental studies have demonstrated vasodilator effects of estrogen/ER on the endothelium, vascular smooth muscle (VSM) and extracellular matrix. Several natural and synthetic estrogenic preparations have been developed for relief of menopausal vasomotor symptoms. However, whether menopausal hormone therapy (MHT) is beneficial in postmenopausal CVD remains controversial. Despite reports of vascular benefits of MHT from observational and experimental studies, randomized clinical trials (RCTs), such as the Heart and Estrogen/progestin Replacement Study (HERS) and the Women’s Health Initiative (WHI), have suggested that, contrary to expectations, MHT may increase the risk of CVD. These discrepancies could be due to age-related changes in sex hormone synthesis and metabolism, which would influence the effective dose of MHT and the sex hormone environment in Post-MW. Age-related changes in the vascular ER subtype, structure, expression, distribution, and post-ER signaling pathways in the endothelium and VSM, along with factors related to the design of RCTs, preexisting CVD condition, and structural changes in the blood vessels architecture have also been suggested as possible causes of MHT failure in CVD. Careful examination of these factors should help in identifying the causes of the changes in the vascular effects of estrogen with age. The sex hormone metabolic pathways, the active versus inactive estrogen metabolites, and their effects on vascular function, the mitochondria, the inflammatory process and angiogenesis should be further examined. Also, the genomic and non-genomic effects of estrogenic compounds should be viewed as integrated rather than discrete responses. The complex interactions between these factors highlight the importance of careful design of MHT RCTs, and the need of a more customized approach for each individual patient in order to enhance the vascular benefits of MHT in postmenopausal CVD.
PMCID: PMC3063102  PMID: 21189141
estrogen; phytoestrogens; estrogen receptor; endothelium; vascular smooth muscle; hypertension; progesterone; testosterone
23.  Correlations of urinary phytoestrogen excretion with lifestyle factors and dietary intakes among middle-aged and elderly Chinese women 
Isoflavones and lignans, two major groups of phytoestrogens, have been postulated to have multiple health benefits, including anti-estrogenic, anti-cancer, pro-cardiovascular health, and ameliorating menopausal symptoms. Urinary excretion of isoflavonoids, including daidzein, genistein, glycitein, O-desmethylangolensin (O-DMA), dihydro-daidzein, dihydrogenistein, and equol, and lignans, including enterodiol and enterolactone, have been used as biomarkers of phytoestrogen exposure in epidemiologic studies. We evaluated the urinary excretion of phytoestrogens and their correlations with lifestyle and dietary factors among 2,165 women who participated in the Shanghai Women’s Health Study (SWHS), a population-based prospective cohort study of 74,942 urban Chinese women aged 40-70 years at study enrollment (1996-2000). The medians (in nmol/mg creatinine) were: isoflavonoids, 17.13; daidzein, 5.57; genistein, 2.41; glycitein, 0.94; O-DMA, 1.52; dihydrodaidzein, 0.81; dihydrogenistein, 0.19; equol, 0.11; enterodiol, 0.30; and enterolactone, 1.18. These levels are 2- (enterodiol) to 126- (O-DMA) fold higher than levels among US women similar in age range with the exception of enterolactone, for which a similar level was observed for both populations. Urinary isoflavonoid excretion was higher among older women and women who engaged in regular exercise and significantly associated with soy food intake, but was inversely related to fruit intake. Urinary excretions of dihydrodaidzein, dihydrogenistein, equol, enterodiol, and enterolactone were inversely associated with body mass index (BMI). Urinary excretion of isoflavones correlated with soy food intake and healthy lifestyle but was inversely associated with fruit intake among middle-aged and elderly Chinese women. Our study adds important information to the rapidly growing body of research on the potential health benefits of phytoestrogens.
PMCID: PMC3316449  PMID: 22493748
Isoflavonoids; lignans; phytoestrogens; dietary intakes; lifestyle factors
24.  Body Mass Index and Breast Cancer Defined by Biological Receptor Status in Pre-Menopausal and Post-Menopausal Women: A Multicenter Study in China 
PLoS ONE  2014;9(1):e87224.
Few studies have investigated the association between body mass index (BMI) and breast cancer with consideration to estrogen/progesterone/human epidermal growth factor type 2 receptor status (ER/PR/HER2) in the breast tissue among Chinese pre- and post-menopausal women.
Four thousand two hundred and eleven breast cancer patients were selected randomly from seven geographic regions of China from 1999 to 2008. Demographic data, risk factors, pathologic features, and biological receptor status of cases were collected from the medical charts. Chi-square test, fisher exact test, rank-correlation analysis, and multivariate logistic regression model were adopted to explore whether BMI differed according to biological receptor status in pre- and post-menopausal women.
Three thousand two hundred and eighty one eligible cases with BMI data were included. No statistically significant differences in demographic characteristics were found between the cases with BMI data and those without. In the rank-correlation analysis, the rates of PR+ and HER2+ were positively correlated with increasing BMI among post-menopausal women (rs BMI, PR+ = 0.867, P = 0.001; rs BMI, HER2+ = 0.636, P = 0.048), but the ER+ rates did not vary by increasing BMI. Controlling for confounding factors, multivariate logistic regression models with BMI<24 kg/m2 as the reference group were performed and found that BMI≥24 kg/m2 was only positively correlated with PR+ status among post-menopausal breast cancer cases (adjusted OR = 1.420, 95% CI: 1.116–1.808, Wald = 8.116, P = 0.004).
Post-menopausal women with high BMI (≥24 kg/m2) have a higher proportion of PR+ breast cancer. In addition to effects mediated via the estrogen metabolism pathway, high BMI might increase the risk of breast cancer by other routes, which should be examined further in future etiological mechanism studies.
PMCID: PMC3906138  PMID: 24489874
25.  Prescribing menopausal hormone therapy: an evidence-based approach 
The constantly changing landscape regarding menopausal hormone therapy (MHT) has been challenging for providers caring for menopausal women. After a decade of fear and uncertainty regarding MHT, reanalysis of the Women’s Health Initiative data and the results of recent studies have provided some clarity regarding the balance of risks and benefits of systemic MHT. Age and years since menopause are now known to be important variables affecting the benefit-risk profile. For symptomatic menopausal women who are under 60 years of age or within 10 years of menopause, the benefits of MHT generally outweigh the risks. Systemic MHT initiated early in menopause appears to slow the progression of atherosclerotic disease, thereby reducing the risk of cardiovascular disease and mortality. During this window of opportunity, MHT might also provide protection against cognitive decline. In older women and women more than 10 years past menopause, the risk-benefit balance of MHT is less favorable, particularly with regard to cardiovascular risk and cognitive impairment. For women entering menopause prematurely (<40 years), MHT ameliorates the risk of cardiovascular disease, osteoporosis, and cognitive decline. Nonoral administration of estrogen offers advantages due to the lack of first-pass hepatic metabolism, which in turn avoids the increased hepatic synthesis of clotting proteins, C-reactive protein, triglycerides, and sex hormone-binding globulin. The duration of combined MHT use is ideally limited to less than 5 years because of the known increase in breast cancer risk after 3–5 years of use. Limitations to use of estrogen only MHT are less clear, since breast cancer risk does not appear to increase with use of estrogen alone. For women under the age of 60 years, or within 10 years of onset of natural menopause, MHT for the treatment of bothersome menopausal symptoms poses low risk and is an acceptable option, particularly when nonhormonal management approaches fail.
PMCID: PMC3897322  PMID: 24474847
hormone therapy; hot flash; flush; menopause

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