Low circulating concentrations of vitamin D metabolites have been associated with increased risk for several diseases and clinical conditions. Large observational studies and surveys have shown that obesity is independently associated with lower serum 25-hydroxyvitamin D (25(OH)D) concentration. Few studies have examined the effect of weight loss on serum 25(OH)D concentration. The purpose of this study was to prospectively examine the effect of weight loss on serum 25(OH)D concentration. Data were collected from 383 overweight or obese women who participated in a 2-year clinical trial of a weight-loss program, in which 51% (N = 195) lost at least 5% of baseline weight by 24 months, 18% (N = 67) lost 5–10%, and 33% (N = 128) lost >10%. Women who did not lose weight at 24 months had an increase in serum 25(OH)D of 1.9 (9.7) ng/ml (mean (SD)); 25(OH)D increased by 2.7 (9.1) ng/ml for those who lost 5–10% of baseline weight; and 25(OH)D increased by 5.0 (9.2) ng/ml for those who lost >10% of baseline weight (P = 0.014). At baseline, 51% (N = 197) of participants met or exceeded the recommended serum concentration of 20 ng/ml. By study end, 64% (N = 230) of overweight or obese women met this goal, as well as 83% (N = 20) of those whose weight loss achieved a normal BMI. These findings suggest that weight loss, presumably associated with a reduction in body fat, is associated with increased serum 25(OH)D concentration in overweight or obese women.
The extent to which nutrient intake may influence bone structure and strength during maximum rates of skeletal growth remains uncertain.
To examine the relationship of dietary intake of micronutrients and bone macro-architectural structure in young girls.
This cross-sectional analysis included baseline data from 363 4th and 6th grade girls enrolled in the Jump-In study. Nutrient intake was assessed using the Harvard Youth/Adolescent Food Frequency Questionnaire. Volumetric BMD (vBMD), bone geometry and strength were measured by peripheral quantitative computed tomography (pQCT). Correlations and regression modeling assessed relations between usual nutrient intake and bone parameters.
In 4th grade girls, metaphyseal and diaphyseal area and circumferences, and diaphyseal strength were associated with vitamin C intake (r = 0.15–0.19; p<0.05). Zinc intake was correlated with diaphyseal vBMD (r = 0.15–0.16; p<0.05). Using multiple linear regression to adjust for important covariates, we observed significant independent associations for vitamin C and zinc with bone parameters. For every mg/d of vitamin C intake trabecular area increased by 11%, cortical strength improved by 14%; and periosteal and endosteal circumferences increased by 5% and 8.6%, respectively. For every mg/d of zinc intake, cortical vBMD increased by <1%. No significant associations were observed in 6th-grade girls.
Results of this study suggests that vitamin C and zinc intake are positively associated with objective measures of bone geometry, size and strength in 4th-grade girls. This indicates potential differences in micronutrient and bone associations at various age-associated stages of bone maturation perhaps indicative of competing hormonal influences.
peripheral quantitative computed tomography (pQCT); preadolescence; bone mineral density (BMD); bone strength; micronutrient intake; vitamin C
Background and purpose
Previous studies have shown that physical inactivity and obesity are risk factors for the development of colorectal cancer. However, controversy exists regarding the influence of these factors on survival in colorectal cancer patients. We evaluated the impact of recreational physical activity and body mass index (BMI) before and after colorectal cancer diagnosis on disease-specific mortality and all-cause mortality.
Patients and Methods
This prospective cohort study included 1339 women enrolled in the Women’s Health Initiative study who were diagnosed with colorectal cancer subsequent to study enrolment. BMI and recreational physical activity were measured before cancer diagnosis at study entry (pre-diagnostic) and after diagnosis at study follow-up interviews (post-diagnostic). We used Cox regression to estimate the association between pre- and post-diagnostic exposures and survival after colorectal cancer diagnosis.
Among women diagnosed with colorectal cancer, 265 (13%) deaths occurred during a median study follow-up of 11.9 years, of which 171 (65%) were attributed to colorectal cancer. Compared with women reporting no pre-diagnostic recreational physical activity, those reporting activity levels of ≥18 MET-hours/week had significantly lower colorectal cancer-specific mortality (hazard ratio (HR)=0.68; 95% confidence interval (CI): 0.41–1.13) and all-cause mortality (HR=0.63; 95% CI: 0.42–0.96). Similar inverse associations were seen for post-diagnostic recreational physical activity. Neither pre- nor post-diagnostic BMI were associated with mortality after colorectal cancer diagnosis.
Recreational physical activity before and after CR colorectal cancer C diagnosis, but not BMI, is associated with more favourable survival.
Physical activity; body mass index; colorectal cancer; survival; postmenopausal
Limonene, a major component in citrus oil, has demonstrated anti-cancer effects in preclinical mammary cancer models. However, the effective oral dose translates to a human dose that may not be feasible for chronic dosing. We proposed to evaluate topical application of limonene to the breast as an alternative dosing strategy.
Materials and Methods
We conducted a mouse disposition study to determine whether limonene would be bio available in the mammary tissue after topical application. SKH-1 mice received topical or oral administration of limonene in the form of orange oil every day for 4 weeks. Plasma and mammary pads were collected 4 hrs after the final dosing. We also conducted an exploratory clinical study to evaluate the safety and feasibility of topically applied limonene in the form of orange oil to the breast. Healthy women were recruited to apply orange oil containing massage oil to their breasts daily for four weeks. Safety and feasibility were assessed by reported adverse events, clinical labs, and usage compliance. Pre and post-intervention nipple aspirate fluid (NAF) and plasma were collected for limonene concentration determination.
The mouse disposition study showed that topical and oral orange oil administration resulted in similar mammary tissue disposition of limonene with no clinical signs of toxicity. In the clinical study, the topical application of limonene containing massage oil to the breast was found to be safe with high levels of usage compliance for daily application, although NAF and plasma limonene concentrations were not significantly changed after the massage oil application.
Our studies showed that limonene is bio available in mammary tissue after topical orange oil application in mice and this novel route of administration to the breast is safe and feasible in healthy women.
Limonene; Topical Application; Safety
Nutrition plays an important role in metabolic syndrome etiology. We examined whether the Women’s Health Initiative (WHI) Dietary Modification Trial influenced metabolic syndrome risk.
48,835 postmenopausal women aged 50–79 years were randomized to a low-fat (20% energy from fat) diet (intervention) or usual diet (comparison) for a mean of 8.1 years. Blood pressure, waist circumference and fasting blood measures of glucose, HDL-cholesterol and triglycerides were measured on a subsample (n= 2816) at baseline and years 1, 3 and 6 post-randomization. Logistic regression estimated associations of the intervention with metabolic syndrome risk and use of cholesterol-lowering and hypertension medications. Multivariate linear regression tested associations between the intervention and metabolic syndrome components.
At year 3, but not years 1 or 6, women in the intervention group (vs. comparison) had a non-statistically significant lower risk of metabolic syndrome (OR=0.83, 95% CI 0.59–1.18). Linear regression models simultaneously modeling the five metabolic syndrome components revealed significant associations of the intervention with metabolic syndrome at year 1 (p<0.0001), but not years 3 (p=0.19) and 6 (p=0.17). Analyses restricted to intervention-adherent participants strengthened associations at years 3 (p=0.05) and 6 (p=0.06). Cholesterol-lowering and hypertension medication use was 19% lower at year 1 for intervention vs. comparison group women (OR=0.81, 95% CI 0.60–1.09). Over the entire trial, fewer intervention vs. comparison participants used these medications (26.0% vs. 29.9%), although results were not statistically significant (p=0.89).
The WHI low-fat diet may influence metabolic syndrome risk and decrease use of hypertension and cholesterol-lowering medications. Findings have potential for meaningful clinical translation.
clinical trials; aging; dietary fat; metabolic syndrome
Colorectal cancer (CRC) incidence and mortality rates are higher in African–Americans as compared with other racial/ethnic groups. The women’s health initiative (WHI) study sample was used to determine whether differences in CRC risk factors explain racial/ethnic differences in incidence and mortality.
The WHI is a longitudinal study of postmenopausal women recruited from 40 centers. Baseline questionnaires were used to collect sociodemographic and health status information. All CRC diagnoses were centrally adjudicated. Cox regression models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for invasive CRC by race/ethnicity.
The study sample included 131,481 (83.7%) White, 14,323 (9.1%) African–American, 6,362 (4.1%) Hispanic, 694 (0.4%) Native American and 4,148 (2.6%) Asian/Pacific Islanders. After a mean follow-up of 10.8 years (SD 2.9), CRC incidence was the highest in African–Americans (annualized rate = 0.14%), followed by Whites and Native Americans (0.12% each), Asian/Pacific Islanders (0.10%), and Hispanics (0.08%). After adjustment for age and trial assignment, Hispanics had a lower risk compared with Whites, HR 0.73 (95% CI: 0.54–0.97) (P = 0.03), and African–Americans had a marginally greater risk, HR 1.16 (95% CI: 0.99–1.34), P = 0.06. Multivariable adjustment attenuated the difference in incidence between African–Americans and Whites (HR 0.99, 95% CI: 0.82–1.20), while strengthening the lower HR for Hispanics (HR 0.68, 95% CI: 0.48–0.97).
African–American/White differences in CRC risk are likely due to sociodemographic/cultural factors other than race.
A number of modifiable exposures could be a focus for reducing CRC risk in African–Americans.
Associations between anthropometric indices of obesity and breast cancer risk may fail to capture the true relationship between excess body fat and risk. We used dual-energy-X-ray-absorptiometry- (DXA-) derived measures of body fat obtained in the Women's Health Initiative to examine the association between body fat and breast cancer risk; we compared these risk estimates with those for conventional anthropometric measurements. The study included 10,960 postmenopausal women aged 50–79 years at recruitment, with baseline DXA measurements and no history of breast cancer. During followup (median: 12.9 years), 503 incident breast cancer cases were diagnosed. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models. All baseline DXA-derived body fat measures showed strong positive associations with breast cancer risk. The multivariable-adjusted HR for the uppermost quintile level (versus lowest) ranged from 1.53 (95% CI 1.14–2.07) for fat mass of the right leg to 2.05 (1.50–2.79) for fat mass of the trunk. Anthropometric indices (categorized by quintiles) of obesity (BMI (1.97, 1.45–2.68), waist circumference (1.97, 1.46–2.65), and waist : hip ratio (1.91, 1.41–2.58)) were all strongly, positively associated with risk and did not differ from DXA-derived measures in prediction of risk.
Calcium and vitamin D may be inversely related to breast cancer risk, in part by affecting mammographic density. However, results from previous, mostly cross-sectional studies have been mixed, and there have been few randomized clinical trials of the effect of calcium and vitamin D supplementation on change in mammographic density.
We assessed the effect of one year of supplementation on mammographic density in 330 postmenopausal women enrolled in the Women’s Health Initiative Hormone Therapy (HT) and Calcium and Vitamin D (CaD) trials. Women were randomized to receive 1000 mg/day of elemental calcium carbonate plus 400 IU/day of vitamin D3 or placebo.
After approximately one year, mammographic density decreased 2% in the CaD supplementation group and increased 1% in the placebo group (ratio of means = 0.97; 95% confidence interval (CI) = 0.81–1.17). Results suggested potential interaction by HT use (P = 0.08). Among women randomized to HT placebo, the ratio of mean density comparing CaD supplementation and placebo groups was 0.82 (95%CI = 0.61–1.11) vs. 1.16 (95%CI = 0.92–1.45) in women randomized to active HT. In sensitivity analyses limited to women taking ≥80% of study supplements, ratios were 0.67 (95%CI = 0.41–1.07) in women not assigned to HT and 1.07 (95%CI = 0.79–1.47) women assigned to HT.
We observed no overall effect of vitamin D and calcium supplementation on mammographic density after one year.
Potential interaction between these nutrients and estrogen as related to mammographic density warrants further study.
breast; calcium; clinical trial; mammography; vitamin D
The food frequency questionnaire approach to dietary assessment is ubiquitous in nutritional epidemiology research. Food records and recalls provide approaches that may also be adaptable for use in large epidemiologic cohorts, if warranted by better measurement properties. The authors collected (2007–2009) a 4-day food record, three 24-hour dietary recalls, and a food frequency questionnaire from 450 postmenopausal women in the Women’s Health Initiative prospective cohort study (enrollment, 1994–1998), along with biomarkers of energy and protein consumption. Through comparison with biomarkers, the food record is shown to provide a stronger estimate of energy and protein than does the food frequency questionnaire, with 24-hour recalls mostly intermediate. Differences were smaller and nonsignificant for protein density. Food frequencies, records, and recalls were, respectively, able to “explain” 3.8%, 7.8%, and 2.8% of biomarker variation for energy; 8.4%, 22.6%, and 16.2% of biomarker variation for protein; and 6.5%, 11.0%, and 7.0% of biomarker variation for protein density. However, calibration equations that include body mass index, age, and ethnicity substantially improve these numbers to 41.7%, 44.7%, and 42.1% for energy; 20.3%, 32.7%, and 28.4% for protein; and 8.7%, 14.4%, and 10.4% for protein density. Calibration equations using any of the assessment procedures may yield suitable consumption estimates for epidemiologic study purposes.
bias (epidemiology); biological markers; diet; energy intake; epidemiologic methods; measurement error; nutrition assessment
Physical health-related quality of life scores have been, inconsistently, associated with breast cancer prognosis. This analysis examined whether change in physical health scores were related to outcomes in women with a history of breast cancer.
2343 breast cancer survivors in a randomized diet trial provided self-reported assessment of physical health-related quality of life at baseline and year 1. Based on change in physical health score, participants were grouped into subpopulations of decreased physical health, no/minimal changes, and increased physical health. Cox regression analysis assessed whether change in physical health (from baseline to year 1) predicted disease-free and overall survival; hazard ratio (HR) was the measure of association.
There were 294 additional breast cancer events and 162 deaths among women followed for 7.3 years. Improvements in physical health were associated with younger age, lower BMI, being employed, not receiving tamoxifen, lower physical activity, and lower baseline physical and mental health. There was no association of change in physical health with additional breast cancer events or mortality among women diagnosed ≤ 2 years before study enrollment. However, among women who entered the study >2 years post diagnosis, the HR for increased compared to decreased physical health was 0.38 (95% CI, 0.16 to 0.85) for all-cause mortality.
These results appear to support testing an intervention to improve physical health in breast cancer patients among patients after the acute stage of treatment.
breast cancer; physical health; survival; mortality
Although studies have shown that physically active breast cancer survivors have lower all-cause mortality, the association between change in physical activity from before to after diagnosis and mortality is not clear. We examined associations among pre- and postdiagnosis physical activity, change in pre- to postdiagnosis physical activity, and all-cause and breast cancer–specific mortality in post-menopausal women. A longitudinal study of 4,643 women diagnosed with invasive breast cancer after entry into the Women’s Health Initiative study of postmenopausal women. Physical activity from recreation and walking was determined at baseline (prediagnosis) and after diagnosis (assessed at the 3 or 6 years post-baseline visit). Women participating in 9 MET-h/wk or more (~3 h/wk of fast walking) of physical activity before diagnosis had a lower all-cause mortality (HR = 0.61; 95% CI, 0.44–0.87; P = 0.01) compared with inactive women in multivariable adjusted analyses. Women participating in ≥9 or more MET-h/wk of physical activity after diagnosis had lower breast cancer mortality (HR = 0.61; 95% CI, 0.35–0.99; P = 0.049) and lower all-cause mortality (HR = 0.54; 95% CI, 0.38–0.79; P < 0.01). Women who increased or maintained physical activity of 9 or more MET-h/wk after diagnosis had lower all-cause mortality (HR = 0.67; 95% CI, 0.46–0.96) even if they were inactive before diagnosis. High levels of physical activity may improve survival in postmenopausal women with breast cancer, even among those reporting low physical activity prior to diagnosis. Women diagnosed with breast cancer should be encouraged to initiate and maintain a program of physical activity.
Nutritional anemia among post-menopausal women is preventable; recent data on prevalence are limited.
To investigate the association between nutrient intakes and anemia prevalence, in relation to both incidence and persistence, in a longitudinal sample of post-menopausal women. We hypothesized that anemia prevalence, incidence and persistence would be greater among women reporting lower intake of B12, folate and iron.
Prospective cohort analysis.
Observational Cohort of the Women’s Health Initiative(WHI-OS) including 93,676 postmenopausal women, age 50 to 79 years, were recruited across the United States at 40 clinical study sites. Women were enrolled between 1993 and 1998; data collection for these analyses continued through 2000.
Main outcome measures
Anemia was defined as a blood hemoglobin concentration of <12.0 mg/dL. Persistent anemia was defined as anemia present at each measurement time point. Diet was assessed by food frequency questionnaire for iron, folate, B12, red meat and cold breakfast cereal; inadequacies were based on dietary reference intakes for women over age 50 years.
Descriptive statistics (mean and standard deviation) were used to characterize the population demographics, anemia rates and diet. Unconditional logistic regression was used to investigate associations between diet and incident and persistent anemia. Associations are presented as odds ratio (OR) and 95% confidence intervals (CI).
Anemia was identified in 3,979 women or 5.5% of the cohort. Inadequate intakes of multiple anemia-associated nutrients were less frequent in non-Hispanic whites (7.4%) than other race/ethnic groups (inadequacies demonstrated in 14.6 to 16.3% of sample). Age, body mass index and smoking were associated with anemia. Women with anemia reported lower intakes of energy, protein, folate, B12, iron, vitamin C and red meat. Multiple (more than a single nutrient) dietary deficiencies were associated with a 21% greater risk of persistent anemia (OR-1.21, 95% CI: 1.05–1.41) and three deficiencies resulted in a 44% increase in risk for persistent anemia (OR-1.44, 95% CI: 1.20–1.73).
Inadequate nutrient intake, a modifiable condition, is associated with greater risk for anemia in post-menopausal women participating in the WHI-OS. Efforts to identify and update incidence estimates for anemia-associated nutrient deficiencies in aging women should be undertaken.
anemia; diet; aging
Previous studies examining the relationship between micronutrient intakes and survival following diagnosis of breast cancer have reported mixed results. This may be partly due to considerable variance in amounts of micronutrients consumed from diet and supplements across studies.
Early stage breast cancer survivors (n=3081) completed four 24-hour dietary and supplement recalls at the baseline assessment (1995 to 2000) and were followed for a median of 9.0 years. Mean micronutrient intakes were compared to dietary reference intakes (DRI) to assess micronutrient adequacy for both users and non-users of supplements. Cox regressions were performed to assess whether intakes of selected micronutrients were associated with all-cause mortality.
412 deaths occurred between baseline and August 2009. Among these women, more supplement users had adequate micronutrient intakes than non-users for 15 out of 17 micronutrients. Less than 10% of supplement users (< 2% of non-supplement users) reported levels that exceeded the tolerable upper limit for each micronutrient except magnesium. After adjusting for age, tumor characteristics, and health status variables, micronutrient intakes were not significantly associated with all-cause mortality.
Dietary supplements may improve overall micronutrient intakes of breast cancer survivors. However, vitamin and mineral intakes were not associated with all-cause mortality.
dietary intake; supplement use; breast cancer survival
Health-related quality of life (HRQOL) has been hypothesized to predict time to additional breast cancer events and all-cause mortality in breast cancer survivors.
Women with early stage breast cancer (n=2967) completed the SF-36 (mental and physical health-related quality of life) and standardized psychosocial questionnaires to assess social support, optimism, hostility, and depression prior to randomization into a dietary trial. Cox regression was performed to assess whether these measures of quality of life and psychosocial functioning predicted time to additional breast cancer events and all-cause mortality; hazard ratios were the measure of association.
There were 492 additional breast cancer events and 301 deaths occurred over a median 7.3 years (range: 0.01–10.8 years) of follow-up. In multivariate models, poorer physical health was associated with both decreased time to additional breast cancer events and all-cause mortality (p trend=0.005 and 0.004, respectively), while greater hostility predicted additional breast cancer events only (p trend=0.03). None of the other psycho-social variables predicted either outcome. The hazard ratios comparing persons with poor (bottom two quintiles) to better (top three quintiles) physical health were 1.42 (95% CI: 1.16, 1.75) for decreased time to additional breast cancer events and 1.37 (95% CI: 1.08, 1.74) for all-cause mortality. Potentially modifiable factors associated with poor physical health included higher BMI, lower physical activity, lower alcohol consumption, and more insomnia (p<0.05 for all).
Interventions to improve physical health should be tested as a means to increase time to additional breast cancer events and mortality among breast cancer survivors.
physical health; breast cancer; oncology; survival
Overweight status after breast cancer treatment may increase a woman’s risk for recurrent disease and/or early onset cardiovascular disease. Green tea has been proposed to promote weight loss and favourably modify glucose, insulin and blood lipids. This pilot study tested the effect of daily decaffeinated green tea consumption for 6 months on weight and body composition, select metabolic parameters, and lipid profiles in overweight breast cancer survivors.
The effect of daily decaffeinated green tea intake on weight, body composition and changes in resting metabolic rate, energy intake, glucose, insulin, HOMA-IR, and lipids was evaluated in overweight breast cancer survivors. Participants had a mean weight of 80.2 kg; BMI 30.1 kg/m2; and body fat 46.4%. Participants (N=54) were randomised to 960 mL decaffeinated green or placebo tea daily for 6 months.
Average tea intake among study completers (N=39) was 5952 ± 1176 mL/week and was associated with a significant reduction in energy intake (P =0.02). Change in body weight of −1.2 kg (green tea) versus + 0.2 kg (placebo) suggests a weight change effect, but was not statistically significant. Decaffeinated green tea intake was associated with elevated HDL levels (P=0.003) and non-significant improvements in the HOMA-IR (−1.1±5.9: green tea; +3.2±7.2: herbal) and the HDL/LDL ratio.
Intake of decaffeinated green tea for 6 months was associated with a slight reduction in body weight and improved HDL and glucose homeostasis in overweight breast cancer survivors.
green tea; overweight; breast cancer survivors
The purpose of this study was to prospectively examine the relationship between anemia and incident fractures of the hip, spine and all skeletal sites in women from diverse racial and ethnic backgrounds enrolled in the Women's Health Initiative (WHI) Observational Study and Clinical Trials.
Prospective cohort study.
40 WHI clinical centers across the US.
Postmenopausal women (n = 160,080), mean age 63.2 (SD: 7.2) years, were recruited and followed for an average of 7.8 years.
Anemia was defined as hemoglobin levels at baseline less than 12 g/dL. All fractures were self-reported. Hip fractures were further confirmed by trained physicians using medical records.
Among the participants 8,739 women (5.5%) were anemic. The age-adjusted incidence rate of hip fractures per 10,000 person years were 21.4 in women with anemia and 15.0 in women without anemia; a higher incidence rate for spine or all fractures in anemic women was also observed. After multiple covariates were included in the Cox proportional hazards models, significant increased fracture risk associated with anemia still existed as demonstrated by the hazards ratios (95% confidence interval) of fractures associated with anemia being 1.38 (1.13–1.68), 1.30 (1.09–1.55) and 1.07 (1.01–1.14) for hip, spine and all-types respectively. No significant racial/ethnic difference was found in these relationships.
A significantly increased fracture risk was observed in multi-ethnic postmenopausal women with anemia. Given the high prevalence of anemia in the elderly population, it is important to better understand the relationship and mechanisms linking anemia to fracture risk.
fracture risk; anemia; hemoglobin; prospective studies
Dietary intake of vitamin D and calcium may be related to risk of breast cancer, possibly by affecting mammographic density. However, the few studies that have evaluated the association between these nutrients and mammographic density in postmenopausal women have had inconsistent results.
We conducted a cross-sectional analysis in 808 participants of the Mammogram Density Ancillary Study of the Women's Health Initiative. Mammographic percent density was measured using baseline mammograms taken prior to randomization of participants in the intervention trials. Vitamin D and calcium intake was assessed with a validated food frequency questionnaire and an inventory of current supplement use both completed at baseline.
After adjustment for age, body mass index, regional solar irradiance and other factors, we did not find a relationship between vitamin D or calcium intake and mammographic density. Mean mammographic percent density in women reporting total vitamin D intakes of <100, 100-199, 200-399, 400-599, ≥600 IU/day were 5.8%, 10.4%, 6.2%, 3.8%, and 5.1%, respectively (P-trend = 0.67). Results in women reporting total calcium intake of <500, 500-749, 750-999, 1000-1199, and ≥1200 mg/day were 7.3%, 4.9%, 7.3%, 6.9%, and 7.l%, respectively (P-trend = 0.51). We did not observe effect modification by overall level of mammographic density or solar irradiance, but supplemental vitamin D use was associated with lower density in younger women (P-interaction=0.009).
These findings do not support a relationship between dietary vitamin D or calcium intake and mammographic density in postmenopausal women. Additional studies should explore these associations in women of different ages and in relation to serum vitamin D levels.
vitamin D; calcium; mammography; breast neoplasms; mammography
Dietary intervention trials aim to change dietary patterns of individuals. Participating in such trials could impact dietary self-report in divergent ways: Dietary counseling and training on portion-size estimation could improve self-report accuracy; participant burden could increase systematic error. Such intervention-associated biases could complicate interpretation of trial results. The authors investigated intervention-associated biases in reported total carotenoid intake using data on 3,088 breast cancer survivors recruited between 1995 and 2000 and followed through 2006 in the Women's Healthy Eating and Living Study, a randomized intervention trial. Longitudinal data from 2 self-report methods (24-hour recalls and food frequency questionnaires) and a plasma carotenoid biomarker were collected. A flexible measurement error model was postulated. Parameters were estimated in a Bayesian framework by using Markov chain Monte Carlo methods. Results indicated that the validity (i.e., correlation with “true” intake) of both self-report methods was significantly higher during follow-up for intervention versus nonintervention participants (4-year validity estimates: intervention = 0.57 for food frequency questionnaires and 0.58 for 24-hour recalls; nonintervention = 0.42 for food frequency questionnaires and 0.48 for 24-hour recalls). However, within- and between-instrument error correlations during follow-up were higher among intervention participants, indicating an increase in systematic error. Diet interventions can impact measurement errors of dietary self-report. Appropriate statistical methods should be applied to examine intervention-associated biases when interpreting results of diet trials.
bias (epidemiology); diet; intervention studies; Markov chain Monte Carlo; measurement error; nutrition assessment; reproducibility of results; validity
Conjugated linoleic acid (CLA) is a class of commercially available fatty acids that have been associated with anticancer properties in rodent models of chemical carcinogenesis. We conducted a pilot study to examine the antitumor effect of dietary CLA in a polyoma virus-middle T antigen (PyMT) mouse model of invasive breast cancer. Virgin 4-week-old PyMT mice were administered a mixed-isomer CLA diet (1% wt/wt) or control AIN-93G diet for 4 weeks (N = 6 and 5, respectively) and tumor burden was assessed at 8 weeks of age. Thoracic mammary glands were prepared as whole mounts with other glands being formalin fixed and paraffin embedded for histology and immunohistochemistry (IHC). Total RNA was prepared for microarray and real-time reverse transcription–polymerase chain reaction analysis. Western blots were performed for protein expression analysis. Tumor incidence was significantly increased in CLA-treated animals compared with controls (P = 0.009) and occurred with extensive lobular–alveolar expansion and loss of mammary adipose tissue. More than 100 genes were downregulated ≥2-fold in the CLA-treated group compared with controls, including adipose-specific markers, as wells as cytoskeletal and adhesion-related genes. This was supported by dramatic decreases in the epithelial adherens E-cadherin and β-catenin as demonstrated by IHC. Taken together, these results suggest that dietary CLA affects the mammary stromal environment, leading to tumor progression and cellular expansion in the PyMT mouse model. Further studies of the potential for cancer promotion are needed, especially because mixed-isomer CLA formulations are sold commercially as a nutritional supplement.
This analysis was conducted to determine whether comorbid medical conditions predict additional breast cancer events and all-cause mortality in women with a history of early stage breast cancer.
Women (n=2542) participating in a randomized diet trial completed a selfadministered questionnaire regarding whether they were currently being treated for a wide variety of diseases (cardiovascular, diabetes, gallbladder, gastrointestinal, arthritis, and osteoporosis) and conditions (high blood pressure, elevated cholesterol level). Height and weight were measured at baseline. Participants were followed for a median of 7.3 years (range 0.8 to 15.0). Cox regression analysis was performed to assess whether comorbidities predicted disease-free and overall survival; hazard ratio (HR) was the measure of association.
Overall, there were 406 additional breast cancer events and 242 deaths. Participants with diabetes had over 2-fold the risk of additional breast cancer events (HR 2.1, 95% CI: 1.3, 3.4) and mortality (HR 2.5, 95% CI: 1.4, 4.4). The presence of multiple comorbidities did not statistically significantly predict additional breast cancer events. However, compared to no comorbidities, participants with 3 or more comorbidities had a HR of 2.1, 95% CI: 1.3, 3.3 for mortality.
Type 2 diabetes was associated with poor breast cancer prognosis. Given that 85 percent of deaths were caused by breast cancer, these findings suggest that multiple comorbidities may reduce the likelihood of surviving additional breast cancer events.
comorbidities; breast cancer; mortality
Total white blood cell (WBC) and neutrophil counts are lower among individuals of African descent due to the common African-derived “null” variant of the Duffy Antigen Receptor for Chemokines (DARC) gene. Additional common genetic polymorphisms were recently associated with total WBC and WBC sub-type levels in European and Japanese populations. No additional loci that account for WBC variability have been identified in African Americans. In order to address this, we performed a large genome-wide association study (GWAS) of total WBC and cell subtype counts in 16,388 African-American participants from 7 population-based cohorts available in the Continental Origins and Genetic Epidemiology Network. In addition to the DARC locus on chromosome 1q23, we identified two other regions (chromosomes 4q13 and 16q22) associated with WBC in African Americans (P<2.5×10−8). The lead SNP (rs9131) on chromosome 4q13 is located in the CXCL2 gene, which encodes a chemotactic cytokine for polymorphonuclear leukocytes. Independent evidence of the novel CXCL2 association with WBC was present in 3,551 Hispanic Americans, 14,767 Japanese, and 19,509 European Americans. The index SNP (rs12149261) on chromosome 16q22 associated with WBC count is located in a large inter-chromosomal segmental duplication encompassing part of the hydrocephalus inducing homolog (HYDIN) gene. We demonstrate that the chromosome 16q22 association finding is most likely due to a genotyping artifact as a consequence of sequence similarity between duplicated regions on chromosomes 16q22 and 1q21. Among the WBC loci recently identified in European or Japanese populations, replication was observed in our African-American meta-analysis for rs445 of CDK6 on chromosome 7q21 and rs4065321 of PSMD3-CSF3 region on chromosome 17q21. In summary, the CXCL2, CDK6, and PSMD3-CSF3 regions are associated with WBC count in African American and other populations. We also demonstrate that large inter-chromosomal duplications can result in false positive associations in GWAS.
Although recent genome-wide association studies have identified common genetic variants associated with total white blood cell (WBC) and WBC sub-type counts in European and Japanese ancestry populations, whether these or other loci account for differences in WBC count among African Americans is unknown. By examining >16,000 African Americans, we show that, in addition to the previously identified Duffy Antigen Receptor for Chemokines (DARC) locus on chromosome 1, another variant, rs9131, and other nearby variants on human chromosome 4 are associated with total WBC count in African Americans. The variants span the CXCL2 gene, which encodes an inflammatory mediator involved in WBC production and migration. We show that the association is not restricted to African Americans but is also present in independent samples of European Americans, Hispanic Americans, and Japanese. This finding is potentially important because WBC mediate or have altered counts in a variety of acute and chronic disorders.
Both alcohol consumption and obesity have been linked with breast cancer morbidity and mortality. An inverse association between alcohol intake and obesity suggests possible confounding between these variables (and perhaps other factors) with breast cancer outcomes.
Alcohol intake (beer, wine, spirits, and total) was examined in 3088 women previously diagnosed and treated for breast cancer, within an intervention trial that targeted vegetables, fiber, and fat but not alcohol or weight loss. Factors associated with baseline alcohol intake were included in Cox proportional hazards models for recurrence and mortality.
Alcohol intake was significantly associated with higher education and physical activity levels. Neither light alcohol intake nor obesity was significantly associated with breast cancer recurrence, but moderate alcohol intake > 300 g/month was protective against all-cause mortality (HR = 0.69, CI=0.49-0.97) in a proportional hazards model adjusted for obesity. Obese women were 61% more likely to be nondrinkers than drinkers, and 76% more likely to be light drinkers than moderate/heavy drinkers. In non-obese women, alcohol intake > 10 g/month was associated with lower risk of all-cause mortality (HR = 0.68, 95% CI = 0.51-0.91).
Light alcohol intake, regardless of body weight, did not increase the risk of breast cancer recurrence or all-cause mortality in this cohort of middle-aged women previously diagnosed with breast cancer. Alcohol intake was associated with other favorable prognostic indicators that may explain its apparent protective effect in non-obese women.
alcohol; breast cancer; obesity; mortality; recurrence
Research suggests that physical activity is associated with improved breast cancer survival, yet no studies have examined the association between post-diagnosis changes in physical activity and breast cancer outcomes. The aim of this study was to determine whether baseline activity and 1-year change in activity are associated with breast cancer events or mortality.
A total of 2,361 post-treatment breast cancer survivors (Stage I–III) enrolled in a randomized controlled trial of dietary change completed physical activity measures at baseline and one year. Physical activity variables (total, moderate–vigorous, and adherence to guidelines) were calculated for each time point. Median follow-up was 7.1 years. Outcomes were invasive breast cancer events and all-cause mortality.
Those who were most active at baseline had a 53% lower mortality risk compared to the least active women (HR = 0.47; 95% CI: 0.26, 0.84; p = .01). Adherence to activity guidelines was associated with a 35% lower mortality risk (HR = 0.65, 95% CI: 0.47, 0.91; p < .01). Neither baseline nor 1-year change in activity was associated with additional breast cancer events.
Higher baseline (post-treatment) physical activity was associated with improved survival. However, change in activity over the following year was not associated with outcomes. These data suggest that long-term physical activity levels are important for breast cancer prognosis.
Exercise; Recurrence; Survival; Behavior; Lifestyle
As the efficacy of treatment for breast cancer has improved, particularly with the use of antiestrogenic therapies, there is an increasing population of long-term breast cancer survivors who seeks care with unique health issues. These patients may be at increased risk for cardiovascular disease (CVD) resulting from excess adiposity and treatment effects. Metabolic syndrome (MetS) and elevated C-reactive protein (CRP), two predictors of CVD, have not been fully evaluated in overweight breast cancer survivors on hormone-modulating agents.
Anthropometric measures, including weight, height, waist and hip circumferences; clinical laboratory assessments, including lipids, glucose, glycoslyated hemoglobin (HbA1c), insulin, and high sensitivity CRP; and body composition and blood pressure (BP) were collected from overweight breast cancer survivors (n = 42). Select measures were used to derive MetS using the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) diagnostic criteria.
Participants had a mean body weight of 83.8 kg and body mass index (BMI) of 31.4 kg/m2. Mean fasting glucose (98 ± 12.9 mg/dL), HbA1c (6.0 ± 0.5 mg/dL), cholesterol (199 ± 33.7 mg/dL), and insulin (16 ±13.2 mg/dL) were all at the upper end of the normal range. MetS was diagnosed in 54.8% of overweight postmenopausal breast cancer survivors. CRP was moderately or severely elevated in 90.5% of the population (mean of 5.1 ± 5.3 mg/dL).
In our sample, overweight breast cancer survivors commonly have MetS and elevated CRP that place them at increased risk for cardiovascular and other metabolic diseases. If replicated in a larger sample, this warrants close medical monitoring to prevent and reduce morbidity and mortality unrelated to breast cancer.
To assess whether the effect of a low-fat dietary pattern on breast cancer incidence varied by report of baseline vasomotor symptoms.
Postmenopausal women age 50 to 79 years enrolled onto the Women's Health Initiative (WHI) Dietary Modification trial from 1993 to 1998 were randomly assigned to a low-fat dietary intervention (n = 19,541) or comparison (n = 29,294). Presence of vasomotor symptoms at baseline was ascertained from a 34-item self-report symptom inventory. Women were queried semi-annually for a new diagnosis of breast cancer. Each case report was verified by medical record and pathology report review by centrally trained WHI physician adjudicators.
Among participants who reported hot flashes (HFs) at baseline (n = 3,375), those assigned to the low-fat diet had a breast cancer rate of 0.27 compared with their counterparts in the control group who had a rate of 0.41 (hazard ratio [HR] = 0.65; 95% CI, 0.42 to 1.01). Among women reporting no HFs (n = 45,160), the breast cancer rate was 0.42 in those assigned to the low-fat diet compared with 0.46 in the control group (HR = 0.93; 95% CI, 0.84 to 1.03; P for interaction = .12 by HF status). Furthermore, the dietary benefits observed seemed to be specific to estrogen receptor (ER) –positive/progesterone receptor (PR) –positive tumors (ER positive/PR positive v other, P for risk = .03). Although women with and without HFs differed with regard to breast cancer risk factors, the effect of the diet intervention on breast cancer incidence by HF status was consistent across risk factor strata.
The results of this trial, which are hypothesis generating, suggest that HFs may identify a subgroup of postmenopausal women whose risk of invasive breast cancer might be reduced with the adoption of a low-fat eating pattern.