Nitrate and nitrite are precursors in the endogenous formation of N-nitroso compounds and nitrate can disrupt thyroid homeostasis by inhibiting iodide uptake. We evaluated nitrate and nitrite intake and risk of thyroid cancer in the Shanghai Women’s Health Study that included 73,317 women, aged 40–70 years enrolled in 1996–2000. Dietary intake was assessed at baseline using a food frequency questionnaire. During approximately 11 years of follow-up, 164 incident thyroid cancer cases with complete dietary information were identified. We used Cox proportional hazards regression to estimate relatives risks (RRs). We determined the nitrate and nitrite contents of foods using values from the published literature and focusing on regional values for Chinese foods. Nitrate intake was not associated with thyroid cancer risk (RRQ4 = 0.93; 95%CI: 0.42–2.07; p for trend = 0.40). Compared with the lowest quartile, women with the highest dietary nitrite intake had about a two-fold risk of thyroid cancer (RRQ4 = 2.05; 95%CI: 1.20–3.51;) but there was not a monotonic trend with increasing intake (p for trend= 0.36). The trend with increasing nitrite intake from animal sources was significant (p for trend = 0.02) and was stronger for nitrite from processed meats (RRQ4 = 1.96; 95%CI: 1.28–2.99; p for trend <0.01). Although we did not observe an association for nitrate as hypothesized, our results suggest that women consuming higher levels of nitrite from animal sources, particularly from processed meat, may have an increased risk of thyroid cancer.
Few studies have investigated vitamin D status in association with modifiable lifestyle factors and clinical characteristics among breast cancer patients, with no studies among Chinese women, who may be at higher risk of vitamin D deficiency. We aimed to evaluate circulating 25-hydroxyvitamin D (25(OH)D) levels in association with clinical and lifestyle factors among 1,940 Chinese breast cancer patients.
Participants included breast cancer cases aged 22–77 from a population-based case-control study conducted in Shanghai, China during 1996–1998 (n = 1,044) and 2002–2005 (n = 896). Circulating 25(OH)D levels were measured in plasma samples (95% collected ≤6 months post-diagnosis). Prevalence ORs and 95% CIs were derived from multinomial logistic regression models, adjusting for age, season, and other factors.
About 23% and 48% of women were vitamin D deficient (<30 nmol/L) or insufficient (30–50 nmol/L), respectively. Tumor characteristics were not associated with vitamin D status. Higher BMI was associated with increased odds of vitamin D deficiency (ORs (95% CIs): 1 (reference), 1.12 (0.85,1.47), and 1.57 (1.02,2.42), for <23, 23–<27.5, and ≥27.5 kg/m2, respectively, Ptrend <0.06). Total physical activity was associated with reduced odds of vitamin D deficiency (ORs (95% CIs):1 (reference), 0.84 (0.59,1.20), 0.65 (0.45,0.93), and 0.69 (0.48,1.00), for <7.65, 7.65–<10.6, 10.6–<13.5, ≥13.5 MET-hours/day, respectively, Ptrend <0.02). Smoking was associated with vitamin D insufficiency and deficiency (ORs (95% CIs): 2.50 (1.07,5.84) and 2.78 (1.11,6.95), respectively).
In the largest study to date, the prevalence of low vitamin D status was high among Chinese breast cancer patients and associated with higher BMI, smoking, and lower physical activity. Our findings support careful monitoring of vitamin D status and recommendations for supplementation and other lifestyle modifications that may improve vitamin D status in breast cancer patients.
Genome-wide association studies have identified approximately 20 susceptibility loci for breast cancer. A cumulative genetic risk score (GRS) was constructed from 10 variants with replicated associations among participants of the Shanghai Breast Cancer Genetics Study (Shanghai, China, 1996–1998 and 2002–2005). Interactions between the GRS and 11 breast cancer risk factors were evaluated. Among the 6,408 study participants, no evidence of effect modification was found with the GRS for age at menarche, age at menopause, age at first live birth/parity, total months of breastfeeding, family history of breast cancer, history of benign breast disease, hormone replacement therapy, body mass index, waist/hip ratio, or regular physical activity. The effect of the GRS was least homogeneous by duration of menstruation; further analysis indicated a nominally significant interaction with one genetic variant. The mitochondrial ribosomal protein S30 gene (MRPS30) rs10941679 was associated with breast cancer risk only among women with more than 30 years of menstruation (odds ratio = 1.15, 95% confidence interval: 1.05, 1.26). Although this multiplicative interaction reached a nominal significance level (P = 0.037), it did not withstand correction for multiple comparisons. In conclusion, this study revealed no apparent interactions between genome-wide association study-identified genetic variants and breast cancer risk factors in the etiology of this common cancer.
Abbreviations: CI, confidence interval; GRS, genetic risk score; OR, odds ratio; SNP, single nucleotide polymorphism.
breast cancer risk; effect measure modification; gene-environment interaction; genetic variants; genome-wide association study
Calcium has been implicated in carcinogenesis and linked to the risk of several cancers in epidemiologic studies; however, few studies have investigated the association of calcium intake with lung cancer risk, particularly among non-smokers.
We evaluated the association of intakes of calcium and related minerals, assessed through a food frequency questionnaire, with lung cancer risk among 71,267 female non-smokers who were cancer free at baseline in the Shanghai Women's Health Study, a population-based, prospective cohort study. Multivariate Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI).
During follow-up through December 2009 (median follow-up time: 11.2 years), 428 incident lung cancer cases accrued. The median intakes of dietary calcium, magnesium, and phosphorus were 441, 266, and 935 mg/day, respectively. Intakes of calcium, phosphorus, and the calcium-to-magnesium (Ca:Mg) ratio were inversely associated with lung cancer risk. The corresponding HRs (95% CIs) for the highest compared with the lowest quartile were 0.66 (0.48, 0.91) for calcium, 0.55 (0.36, 0.85) for phosphorus, and 0.62 (0.47, 0.82) for the Ca:Mg ratio. No association was observed for dietary magnesium intake or the use of calcium- or vitamin D-containing supplements.
Conclusions and Impact
Our study provides some of the first evidence suggesting a possible role for increasing dietary calcium intake in lung cancer prevention among female non-smokers, especially in populations with relatively low calcium intake.
calcium; dietary intake; lung cancer; women; non-smokers
Carotenoids, micronutrients in fruits and vegetables, may reduce breast cancer risk. Most, but not all, past studies of circulating carotenoids and breast cancer have found an inverse association with at least one carotenoid, although the specific carotenoid has varied across studies.
We conducted a pooled analysis of eight cohort studies comprising more than 80% of the world’s published prospective data on plasma or serum carotenoids and breast cancer, including 3055 case subjects and 3956 matched control subjects. To account for laboratory differences and examine population differences across studies, we recalibrated participant carotenoid levels to a common standard by reassaying 20 plasma or serum samples from each cohort together at the same laboratory. Using conditional logistic regression, adjusting for several breast cancer risk factors, we calculated relative risks (RRs) and 95% confidence intervals (CIs) using quintiles defined among the control subjects from all studies. All P values are two-sided.
Statistically significant inverse associations with breast cancer were observed for α-carotene (top vs bottom quintile RR = 0.87, 95% CI = 0.71 to 1.05, Ptrend = .04), β-carotene (RR = 0.83, 95% CI = 0.70 to 0.98, Ptrend = .02), lutein+zeaxanthin (RR = 0.84, 95% CI = 0.70 to 1.01, Ptrend = .05), lycopene (RR = 0.78, 95% CI = 0.62 to 0.99, Ptrend = .02), and total carotenoids (RR = 0.81, 95% CI = 0.68 to 0.96, Ptrend = .01). β-Cryptoxanthin was not statistically significantly associated with risk. Tests for heterogeneity across studies were not statistically significant. For several carotenoids, associations appeared stronger for estrogen receptor negative (ER−) than for ER+ tumors (eg, β-carotene: ER−: top vs bottom quintile RR = 0.52, 95% CI = 0.36 to 0.77, Ptrend = .001; ER+: RR = 0.83, 95% CI = 0.66 to 1.04, Ptrend = .06; Pheterogeneity = .01).
This comprehensive prospective analysis suggests women with higher circulating levels of α-carotene, β-carotene, lutein+zeaxanthin, lycopene, and total carotenoids may be at reduced risk of breast cancer.
Little is known about the etiology of pancreatic cancer. Epidemiological studies on tea consumption and pancreatic cancer risk have been inconclusive. The purpose of the present study was to investigate the association between green tea drinking and the risk of pancreatic cancer in urban Shanghai, China.
In this population-based case-control study conducted in urban Shanghai, 908 cases of pancreatic cancer and 1067 healthy controls were recruited. Information on tea drinking, including type of tea, amount of tea consumption, temperature of tea, and the duration of regular tea drinking, were collected via interview questionnaire.
We examined the association of multiple tea drinking habits with the risk of pancreatic cancer. In women, regular green tea drinking was associated with 32% reduction of pancreatic cancer risk (OR 0.68, 95% CI 0.48–0.96), compared to those who did not drink tea regularly. Increased consumption and longer duration of tea drinking were both associated with reduced pancreatic cancer risk in women. Among regular tea drinkers, lower temperature of tea was associated with reduced risk of pancreatic cancer in both men and women, independent of amount or duration of tea drinking.
Habits of green tea drinking, including regular drinking, amount of consumption, persistence of the habit, and tea temperature, may lower pancreatic cancer risk.
pancreatic cancer; tea; case-control study; China
B vitamins and methionine have been postulated to have potential effects on carcinogenesis; however, findings from previous epidemiologic studies on B vitamins, methionine, and lung cancer risk are inconsistent. We investigated associations of dietary intakes of B vitamins (i.e., riboflavin, niacin, vitamin B6, folate, and vitamin B12) and methionine with lung cancer risk among female never smokers.
The Shanghai Women’s Health Study, a population-based, prospective cohort study, included 74,941 women. During a median follow-up of 11.2 years, 428 incident lung cancer cases accrued among 71,267 women with no history of smoking or cancer at baseline. Baseline dietary intakes were derived from a validated, interviewer-administered food frequency questionnaire. Cancer incidence and vital status were ascertained through annual linkage to the Shanghai Cancer Registry and Shanghai Vital Statistics Registry databases and through biennial in-person follow-ups with participants. Adjusted hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox regression.
Dietary riboflavin intake was inversely associated with lung cancer risk (HR = 0.62; 95% CI = 0.43–0.89; P-trend = 0.03 for the highest quartile compared with the lowest). A higher than median intake of methionine was associated with lower risk of lung cancer (HR = 0.78; 95% CI = 0.60–0.99), however, there was no dose-response relation. Intakes of other B vitamins were not associated with lung cancer risk.
Our study suggests that dietary riboflavin intake may be inversely associated with lung cancer risk among female never smokers, which warrants further investigation.
B vitamins; methionine; lung cancer; never smokers; women
We aimed to examine the association between BMI and the risk of death from pancreas cancer in a pooled analysis of data from the Asia Cohort Consortium.
The data for this pooled-analysis included 883,529 men and women from 16 cohort studies in Asian countries. Cox proportional-hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for pancreas cancer mortality in relation to BMI. Seven predefined BMI categories (<18.5, 18.5–19.9, 20.0–22.4, 22.5–24.9, 25.0–27.4, 27.5–29.9, ≥30) were used in the analysis, with BMI of 22.5–24.9 serving as the reference group. The multivariable analyses were adjusted for known risk factors, including age, smoking, and history of diabetes.
We found no statistically significant overall association between each BMI category and risk of death from pancreas cancer in all Asians, and obesity was unrelated to mortality risk in both East Asians and South Asians. Age, smoking, and history of diabetes did not modify the association between BMI and risk of death from pancreas cancer. In planned subgroup analyses among East Asians, an increased risk of death from pancreas cancer among those with a BMI<18.5 was observed for individuals with a history of diabetes; HR = 2.01(95%CI: 1.01–4.00) (p for interaction=0.07).
The data do not support an association between BMI and risk of death from pancreas cancer in these Asian populations.
body mass index; insulin resistance; obesity; overweight; pancreatic cancer
The mitochondrial DNA (mtDNA) 4977-bp deletion (ΔmtDNA4977 mutation) is one of the most frequently observed mtDNA mutations in human tissues, and may play a role in carcinogenesis. Only a few studies have evaluated ΔmtDNA4977 mutation in breast cancer tissue, and the findings have been inconsistent, which may be due to methodological differences. In this study, we developed a quantitative real-time PCR assay to assess the level of the ΔmtDNA4977 mutation in tumor tissue samples from 55 primary breast cancer patients and 21 patients with benign breast disease (BBD). The ΔmtDNA4977 mutation was detected in all of the samples with levels varying from 0.000149% to 7.0%. The ΔmtDNA4977 mutation levels were lower in tumor tissues than in adjacent normal tissues in both breast cancer and BBD subjects. The differences, however, were not statistically significant. No significant difference between breast cancer and BBD patients was found in the ΔmtDNA4977 mutation levels of tumor tissues and adjacent normal tissues. The ΔmtDNA4977 mutation levels were not significantly associated with clinicopathological characteristics (age, histology, tumor stage, and ER/PR status) in breast cancer or BBD patients. These results do not support the notion that the mitochondrial DNA 4977-bp deletion plays a major role in breast carcinogenesis.
benign breast disease; breast cancer; mtDNA 4977 mutation; quantitative real-time PCR assay
The authors prospectively evaluated the association of soy food intake with lung cancer risk, overall and by tumor aggressiveness, and performed a meta-analysis of published data. Included in the analysis were 71,550 women recruited into the Shanghai Women's Health Study (Shanghai, China) in 1997–2000. Usual soy food intake was assessed at baseline and reassessed during follow-up through in-person interviews. During a mean follow-up period of 9.1 years, 370 incident lung cancer cases were identified; 340 patients were lifetime never smokers. After adjustment for potential confounders, soy food intake was inversely associated with subsequent risk of lung cancer (Ptrend = 0.004); the hazard ratio for the highest quintile of intake compared with the lowest was 0.63 (95% confidence interval: 0.44, 0.90). This inverse association appeared predominately among women with later age at menopause (Pinteraction = 0.01) and for aggressive lung cancer as defined by length of survival (<12 months vs. ≥12 months; Pheterogeneity = 0.057). Meta-analysis of 7 studies conducted among nonsmokers found a summary relative risk of 0.59 (95% confidence interval: 0.49, 0.71) for the highest categories of soy or isoflavone intake versus the lowest. This study suggests that soy food consumption may reduce lung cancer risk in nonsmoking women, particularly for aggressive tumors, and its effect may be modified by endogenous estrogens.
cohort studies; lung neoplasms; meta-analysis; risk; soy foods; women
Nine previously reported associations between single nucleotide polymorphisms (SNPs) and breast cancer outcomes from the Shanghai Breast Cancer Study (Stage 1) were further evaluated in relation to disease-free survival (DFS) and overall survival (OS) among 5,192 additional breast cancer patients (Stage 2).
Hazard ratios (HR) and 95% confidence intervals (CI) were calculated by proportional hazards regression in models adjusted for age, disease stage, estrogen and progesterone receptor status, and treatment regimens.
Two SNPs had generally consistent results and significant associations with OS in combined analyses. Compared to women with MMP7 rs11225297 AA genotypes, OS was moderately better for women with AT genotypes (HR: 0.8, 95% CI: 0.7-1.0) and much better for women with TT genotypes (HR: 0.4, 95% CI: 0.2-0.8). Compared to women with MMP8 rs11225395 CC genotypes, OS was slightly better for women with CT genotypes (HR: 0.9, 95% CI: 0.7-1.1) and moderately better for women with TT genotypes (HR: 0.6, 95% CI: 0.4-0.9). Joint analysis showed significant dose-response relationships with increasing numbers of rare alleles for both OS (p<0.001) and DFS (p=0.001)
A functional variant in MMP8 and a SNP in high linkage disequilibrium with a functional variant in MMP7 were significantly associated with breast cancer survival in a large two-stage survival study among Chinese women. This supports the hypothesis that SNPs in MMP genes may influence breast cancer prognosis; additional research on these and other SNPs in genes important in metastasis, angiogenesis, and the regulation of the tumor microenvironment is warranted.
breast cancer; survival; genetic variants; replication; matrix metalloproteinases
Little is known about the association of circulating 25-hydroxyvitamin D (25[OH]D) and blood pressure (BP) parameters, and hypertension in non-Western populations that have not yet been exposed to foods fortified with vitamins and seldom use vitamin D supplements. A cross-sectional analysis of plasma 25(OH)D levels in association with BP measures was performed for 1460 participants (405 men and 1055 women, aged 40–75 years) of two large cohort studies in Shanghai. Multivariable linear and logistic regressions were conducted. Overall, the prevalence of vitamin D deficiency was 55.8% using NHANES/USA criteria and 29.9% using WHO criteria. The median plasma 25(OH)D level was 38.0 nmol/L for men and 33.6 nmol/L for women (P<0.01) among subjects who were not on antihypertensive drugs. Among men, BP parameters (systolic BP, diastolic BP, and MAP) were significantly and inversely associated with higher quintiles of 25(OH)D compared with the lowest quintile (Ptrend <0.05 for all). Vitamin D non-deficient status (WHO criteria) was inversely associated with hypertension (ORadj =0.29, 95% CI: 0.10–0.82). An inverse association was also found between hypertension and the highest quintile of 25(OH)D (ORadj =0.16, 95% CI: 0.04–0.65 for ≥50.6 nmol/L; Ptrend =0.02). Among women, no significant associations were found for BP parameters and hypertension. The present study shows that vitamin D deficiency is common among adults in urban China. Circulating 25(OH)D levels were inversely related to levels of individual BP parameters and hypertension among middle-aged and elderly men but not in women. More research is needed to investigate the potential gender differential associations.
Blood pressure parameters; Hypertension; 25(OH)D; Gender; China
Background Whether soy food consumption may protect against coronary heart disease (CHD) remains controversial. No previous study has used biomarkers of soy intake in assessing the relationship between soy consumption and CHD. Biomarkers that reflect both intake and metabolism may be more informative than self-reports of dietary intake.
Methods We examined associations of urinary isoflavonoids, a biomarker of soy or soy isoflavone intake, with risk of CHD in a case–control study nested within two prospective cohort studies of Chinese adults in Shanghai. Cases were defined as subjects with no history of CHD at baseline who developed incident CHD during follow-up. Control subjects were randomly selected from those who remained free of CHD and matched to cases by sex, age, date and time of sample collection and antibiotic use. Baseline urinary isoflavonoids (daidzein, genistein, glycitein, equol, O-desmethylangolensin, dihydrodaidzein and dihydrogenistein) were compared between cases (n = 377) and control subjects (n = 753). Conditional logistic regression was used to evaluate the associations.
Results Total urinary isoflavonoids were not associated with CHD in either women or men. However, urinary equol excretion showed a significant inverse association with CHD in women. The adjusted odds ratios (95% confidence intervals) for CHD across increasing quartiles of equol levels in women were 1 (reference), 0.61 (0.32, 1.15), 0.51 (0.26, 0.98) and 0.46 (0.24, 0.89) (P = 0.02 for trend).
Conclusions Our study suggests for the first time that equol, a bioactive metabolite of soy isoflavone daidzein, may be inversely associated with risk of CHD in women.
coronary disease; isoflavones; soy foods
Telomeres are specialized chromatin structures essential for maintenance of chromosomal integrity and stability. Abnormal alteration of telomere length has been linked to several cancers; however, epidemiologic evidence regarding the association of telomere length with colorectal cancer risk has been conflicting.
We conducted a nested case-control study to evaluate the association between telomere length and colorectal cancer risk using peripheral blood samples collected prior to cancer diagnosis. The study included 441 women with incident colorectal cancer and 549 matched controls. Monochrome multiplex quantitative PCR was applied to measure relative telomere length. Multiple logistic regressions were used to derive adjusted odds ratios (OR) with 95% confidence intervals (CI) as the measure of association between telomere length and subsequent colorectal cancer risk.
A U-shaped association was observed between telomere length and colorectal cancer risk (test for nonlinearity P = 0.0112). Women with telomere length in the third quintile (40th to 60th percentiles) had the lowest risk of colorectal cancer, and the risks were elevated with a shorter or longer telomere length. This U-shaped association did not statistically differ for colon cancer and rectum cancer.
Conclusions and Impact
Our prospective study revealed a U-shaped association between telomere length in peripheral blood cells and colorectal cancer risk. Our findings provide strong evidence that both very short and very long telomeres are associated with increased risk of colorectal cancer.
Abnormal sleep duration, either long or short, is associated with disease risk and mortality. Little information is available on sleep duration and its correlates among Chinese women.
Using information collected from 68,832 women who participated in the Shanghai Women’s Health Study (SWHS), we evaluated sleep duration and its correlations with sociodemographic and lifestyle factors, health status, and anthropometric measurements and their indexes using polynomial logistic regression.
The mean age of the study population was 59.6 years (SD=9.0; range: 44.6–79.9 years) at time of sleep duration assessment. Approximately 80% of women reported sleeping 6–8 hours per day, 11.5% slept five hours or less, and 8.7% slept nine hours or more. As expected, age was the strongest predictor for sleep duration and was negatively correlated with sleep duration. In general, sleep duration was positively associated with energy intake, intakes of total meat and fruits, body mass index (BMI), waist-hip ratio (WHR), and waist circumference (WC) after adjustment for age and other factors. Both short and long sleep duration were negatively associated with education level, family income, and leisure-time physical activity and positively associated with number of live births, history of night shift work, and certain chronic diseases, compared to sleep duration around seven hours/day (6.5–7.4 hours/day). Short sleep duration was related to tea consumption and passive smoking. Long sleep duration was related to menopausal status and marital status.
In this large, population-based study, we found that sleep duration among middle-aged and elderly Chinese women was associated with several sociodemographic and lifestyle factors and with disease status. The main limitation of the study is the cross-sectional design that does not allow us to draw any causal inference. However, this study provides information for future investigation into the nature of these associations so that recommendations can be developed to reduce sleep problems in middle-aged and elderly Chinese women. It also provides important information on potential confounders for investigation of sleep duration on health outcomes in this population.
Sleep duration; socio-economic factor; lifestyle; health status; BMI; correlation; Chinese
We conducted a genome-wide association study of gastric cancer (GC) and esophageal squamous cell carcinoma (ESCC) in ethnic Chinese subjects in which we genotyped 551,152 single nucleotide polymorphisms (SNPs). We report a combined analysis of 2,240 GC cases, 2,115 ESCC cases, and 3,302 controls drawn from five studies. In logistic regression models adjusted for age, sex, and study, multiple variants at 10q23 had genome-wide significance for GC and ESCC independently. A notable signal was rs2274223, a nonsynonymous SNP located in PLCE1, for GC (P=8.40×1010; per allele odds ratio (OR) = 1.31) and ESCC (P=3.85×10−9; OR = 1.34). The association with GC differed by anatomic subsite. For tumors located in the cardia the association was stronger (P=4.19 × 10−15; OR= 1.57) and for those located in the noncardia stomach it was absent (P=0.44; OR=1.05). Our findings at 10q23 could provide insight into the high incidence rates of both cancers in China.
Most epidemiological studies evaluating the association of fruit and vegetable intakes on lung cancer risk were conducted in North American and European countries. We investigated the association of intakes of fruits, vegetables, dietary vitamins A and C, and folate with lung cancer risk among 61,491 Chinese adult men who were recruited to the Shanghai Men's Health Study, a population-based, prospective cohort study. Baseline dietary intake was assessed through a validated food frequency questionnaire during in-home visits. Multivariate Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) of lung cancer risk associated with dietary intakes. During a median follow-up of 5.5 years, 359 incident lung cancer cases accrued after the first year of follow-up and 68.8% of them were current smokers. Intakes of green leafy vegetables, β-carotene-rich vegetables, watermelon, vitamin A, and carotenoids were inversely associated with lung cancer risk; the corresponding HR (95% CI) comparing the highest with the lowest quartiles were 0.72 (0.53–0.98), 0.69 (0.51–0.94), 0.65 (0.47–0.90), 0.63 (0.44–0.88), and 0.64 (0.46–0.88). Intake of all fruits and vegetables combined was marginally associated with lower risk. Our study suggests that the consumption of carotenoid-rich vegetables is inversely associated with lung cancer risk.
fruits; vegetables; carotenoids; dietary intake; lung cancer; epidemiological
Vitamin D deficiency has been consistently associated with obesity. However, it is unclear whether vitamin D deficiency is the cause or consequence of obesity. We investigated this question by evaluating the association between genetic variants in vitamin D metabolism pathway genes and obesity-related traits. Using directly genotyped and imputed data from a genome-wide association (GWA) study of 6,922 women aged 25–70 years, we examined the association of 198 SNPs in vitamin D pathway genes (CYP27A1, CYP27B1, CYP24A1, CYP2R1, GC, and VDR) with body mass index (BMI) and body weight. Per allele beta (β) estimates were calculated for this association using linear regression models, controlling for age, square of age, menopausal status, and sample sets. Overall, only two SNPs (rs2248359 in CYP24A1 and rs10832313 in CYP2R1) had a nominally significant association with BMI and weight (P=0.02 for both) with no variation observed by menopausal status, physical activity, or dietary energy intake. None of the SNPs examined in the VDR gene were associated with BMI or weight. Our findings suggest that common genetic variations in vitamin D pathway genes do not play a major role in obesity among Chinese women.
genetic variants; body mass index; body weight; obesity; vitamin D pathway; genome-wide association study; women; China
Previous studies suggest that melatonin may act on cancer growth through a variety of mechanisms, most notably by direct anti-proliferative effects on breast cancer cells and via interactions with the estrogen pathway. Three genes are largely responsible for mediating the downstream effects of melatonin: melatonin receptors 1a and 1b (MTNR1a and MTNR1b), and Arylalkylamine N-acetyltransferase (AANAT). It is hypothesized that genetic variation in these genes may lead to altered protein production or function. To address this question, we conducted a comprehensive evaluation of the association between common single nucleotide polymorphisms (SNPs) in the MTNR1a, MTNR1b, and AANAT genes and breast cancer risk among 2,073 cases and 2,083 controls, using a two-staged analysis of genome-wide association (GWAS) data among women of the Shanghai Breast Cancer Study. Results demonstrate two SNPS were consistently associated with breast cancer risk across both study stages. Compared with MTNR1b rs10765576 major allele carriers (GG or GA), a decreased risk of breast cancer was associated with the AA genotype (OR=0.78, 95% CI=0.62–0.97, p=0.0281). Although no overall association was seen in the combined analysis, the effect of MTNR1a rs7665392 was found to vary by menopausal status (p-value for interaction=0.001). Premenopausal women with the GG genotype were at increased risk for breast cancer as compared to major allele carriers (TT or TG) (OR=1.57, 95% CI=1.07–2.31, p=0.020), while post-menopausal women were at decreased risk (OR=0.58, 95% 0.36–0.95, p=0.030). No significant breast cancer associations were found for variants in AANAT. These results suggest that common genetic variation in the MTNR1a and 1b genes may contribute to breast cancer susceptibility, and that associations may vary by menopausal status. Given that multiple variants in high linkage disequibrium with MTNR1b rs76653292 have been associated with altered function or expression of insulin and glucose family members, further research may focus on clarifying this relationship.
Melatonin; gene; polymorphism; breast cancer; risk
The effects of diet on breast cancer are controversial and whether the effects vary with hormone receptor status has not been well investigated. This study evaluated the associations of dietary factors with risk for breast cancer overall and by hormone receptor status of tumors among Chinese women.
The Shanghai Breast Cancer Study, a large, population-based, case-control study, enrolled 3,443 cases and 3,474 controls in 1996–1998 (phase I) and 2002–2004 (phase II); 2,676 cases had ER and PR data. Dietary intake was assessed using a validated, quantitative, food frequency questionnaire (FFQ). Odds ratios (ORs) and 95% confidence intervals (95% CI) were derived from multivariate, polychotomous, unconditional logistic regression models.
Total vegetable intake was inversely related to breast cancer risk, with an adjusted OR for the highest quintile of 0.80 (95% CI = 0.67–0.95; P trend=0.02). Reduced risk was also related to high intake of allium vegetables (P trend = 0.01) and fresh legumes (P trend = 0.0008). High intake of citrus fruits and rosaceae fruits were inversely associated with breast cancer risk (P trend = 0.003 and P trend = 0.004, respectively), although no consistent association was seen for total fruit intake. Elevated risk was observed for all types of meat and fish intake (all P trend <0.05), while intakes of eggs and milk were associated with a decreased risk of breast cancer (both P trend <0.05). There was little evidence that associations with dietary intakes varied across the four tumor subtypes or between ER+/PR+ and ER−/PR− tumors (P for heterogeneity >0.05).
Our results suggest that high intake of total vegetables, certain fruits, milk, and eggs may reduce the risk of breast cancer, while high consumption of animal-source foods may increase risk. The dietary associations did not appear to vary by ER/PR status.
This study evaluated associations of various anthropometric measures of adiposity with a panel of inflammatory and oxidative stress markers in a relatively lean population of Chinese women.
This analysis included 1,005 Chinese women aged 40-70 years. Plasma concentrations of inflammatory and oxidative stress markers were measured. Anthropometric measurements were taken by trained interviewers.
Body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) were all positively and linearly associated with the inflammatory markers, CRP, TNF-α, soluble TNF-receptor 1 (sTNF-R1), and IL-6. A significant positive association of these measures of adiposity with the oxidative stress marker F2-IsoP-M, a metabolite of F2-IsoPs, but with not F2-IsoPs was found. Differences in biomarkers between extreme quartiles of anthropometric measurements varied widely, ranging from 9.7% for sTNF-R1 to 162.0% for CRP. For each specific biomarker, various anthropometric measurements exhibited similar ability to explain variations in the biomarker, with the biggest partial r2 (11%) observed for CRP.
This study suggests that both general adiposity (measured by BMI) and central adiposity (measured by WC and WHtR) are positively and similarly associated with various markers of inflammation and oxidative stress in relatively lean Chinese women. The metabolite F2-IsoP-M of F2-IsoPs may be a better marker of in vivo oxidative stress than its parent compounds.
adiposity; inflammation; oxidative stress; biomarker
Correspondence to: Xiao-Ou Shu, MD, PhD, Vanderbilt Epidemiology Center, 2525 West End Ave, Ste 600 (IMPH), Nashville, TN 37203-1738 (e-mail: firstname.lastname@example.org) and Yong-Bing Xiang, MD, MSc, Shanghai Cancer Institute, No. 25, Lane 2200, Xie Tu Road, Shanghai 200032, People’s Republic of China (e-mail: email@example.com).Background
Epidemiologic studies on the relationship between vitamin intake and liver cancer risk are sparse and inconsistent.
We evaluated vitamin intake from diet and supplements and risk of liver cancer in 132 837 women and men from China who were recruited into the Shanghai Women’s Health Study from 1997 to 2000 or the Shanghai Men’s Health Study from 2002 to 2006. In-person interviews, using a validated food-frequency questionnaire, were conducted to collect data on dietary habits. Follow-up consisted of in-person surveys and record linkage. Hazard ratios and 95% confidence intervals were estimated using Cox proportional hazard models with adjustment for potential confounders to compare liver cancer risk among participants with high vs low vitamin intake. All statistical tests were two-sided.
After excluding the first 2 years of follow-up, 267 participants (including 118 women and 149 men) developed liver cancer during an average of 10.9 (Shanghai Women’s Health Study) or 5.5 (Shanghai Men’s Health Study) years of follow-up. Dietary vitamin E intake was inversely associated with liver cancer risk (P
trend = .01), as was vitamin E supplement use (hazard ratio = 0.52, 95% confidence interval = 0.30 to 0.90). This association was consistent among participants with and without self-reported liver disease or a family history of liver cancer. Vitamin C and multivitamin use was associated with increased risk among participants with self-reported liver disease or family history of liver cancer, whereas intake of vitamin C and other vitamins from dietary sources was unrelated to liver cancer risk.
Vitamin E intake, either from diet or supplements, may reduce the risk of liver cancer.
To identify novel genetic factors for colorectal cancer (CRC), we conducted a genome-wide association study in East Asians. By analyzing genome-wide data in 2,098 cases and 5,749 controls, we selected 64 promising SNPs for replication in an independent set of samples including up to 5,358 cases and 5,922 controls. We identified four SNPs with a P-value of 8.58 × 10−7 to 3.77 × 10−10 in the combined analysis of all East Asian samples. Three of the four SNPs were replicated in a study conducted among 26,060 European descendants with a combined P-value of 1.22 × 10−10 for rs647161 (5q31.1), 6.64 × 10−9 for rs2423279 (20p12.3), and 3.06 × 10−8 for rs10774214 (12p13.32 near the CCND2 gene), respectively, derived from the meta-analysis of data from both East Asian and European populations. This study identified three new CRC susceptibility loci and provides additional insight into the genetics and biology of CRC.
Soy and some of its constituents, such as isoflavones, have been shown to affect the inflammatory process in animal studies. The association between soy food intake and inflammatory markers has not been evaluated adequately in humans.
Our aim was to evaluate whether higher intake of soy foods was inversely associated with inflammatory markers in 1,005 middle-aged Chinese women.
In this cross-sectional study, dietary intake of soy foods was assessed by a validated food frequency questionnaire and by a 24-hour recall when biospecimens were procured. A general linear model was used to estimate the geometric means of selected inflammatory markers, including interleukin-6 (IL-6), IL-1β, tumor necrosis factor-α (TNFα), soluble IL-6 receptor, soluble GP130, soluble TNF receptors 1 and 2, and C-reactive protein, across categories of soy food intake after adjusting for age, lifestyle and dietary factors, and history of infectious or inflammation-related diseases.
We found that multivariable-adjusted geometric mean concentrations of IL-6 and TNFα were inversely associated with quintiles of soy food intake, with a difference between the highest and lowest quintiles of 25.5% for IL-6 (P for trend = 0.008) and 14% for TNFα (P for trend = 0.04). Similar inverse associations were found for TNFα (P for trend = 0.003), soluble TNF receptor 1 (P for trend=0.01), soluble TNF receptor 2 (P for trend=0.02), IL-1β (P for trend=0.05), and IL-6 (P for trend=0.04) when soy food consumption was assessed by the frequency of consumption in the preceding 24 hours. No significant associations were found for other markers studied.
This study suggests that soy food consumption is related to lower circulating levels of IL-6, TNFα, and soluble TNF receptors 1 and 2 in Chinese women.
Soy; Inflammation; Interleukin-1β; Interleukin-6; Tumor necrosis factor-α
Obesity is associated with circulating levels of adiponectin and leptin and endometrial cancer risk. Little is known about whether single nucleotide polymorphisms (SNPs) in the genes that encode adiponectin (ADIPOQ), leptin (LEP), adiponectin receptor 1 (ADIPOR1), adiponectin receptor 2 (ADIPOR2), and leptin receptor (LEPR) are associated with endometrial cancer.
We selected 87 tagging SNPs to capture common genetic variants in these five genes. These SNPs were evaluated in 1,028 endometrial cancer cases and 1,932 community controls recruited from Chinese women. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs).
Three of the 10 SNPs evaluated in the ADIPOQ gene were significantly associated with reduced cancer risk. The OR for women homozygous for the minor allele (A/A) for rs3774262 was 0.68 (95% CI: 0.48-0.97) compared with women homozygous for the major allele (G/G). Similar results were found for SNPs rs1063539 and rs12629945 in ADIPOQ, which were in linkage disequilibrium with rs3774262. These associations became non-significant after Bonferroni correction was applied. Controls with the minor allele A at rs3774262 had lower weight, waist circumference, hip circumference, and BMI than controls with the major allele G (all P<0.05). Women homozygous for the minor allele (T/T) of rs2071045 in the LEP gene also had significantly lower risk (OR=0.70 (0.54-0.90)) than women homozygous for the major allele (C/C). No other SNPs in the LEP, ADIPOR1, ADIPOR2, or LEPR genes were found to be associated with cancer risk.
Although a chance finding cannot be ruled out, the consistency of findings for gene-endometrial cancer risk and gene-obesity measurements suggests that genetic polymorphisms in the ADIPOQ genes may play a role in endometrial cancer development.
adipokine; adiponectin; leptin; polymorphism; obesity; endometrial cancer