Shanghai Women's Health Research Articles

Polycyclic aromatic hydrocarbons: determinants of urinary 1-hydroxypyrene glucuronide concentration and risk of colorectal cancer in the Shanghai Women’s Health Study

BackgroundAssociations between polycyclic aromatic hydrocarbons (PAHs) and colorectal cancer have been reported previously but few studies have characterized PAH exposure using biological measurements. We evaluated colorectal cancer risk in relation to urinary concentration of 1-hydroxypyrene glucuronide (1-OHPG), a polycyclic aromatic hydrocarbon (PAH) metabolite, and assessed determinants of PAH exposure among controls in the Shanghai Women’s Health Study (SWHS).MethodsConcentrations of 1-OHPG were measured in spot urine samples collected from 343 colorectal cancer cases and 343 individually matched controls. Questionnaires were administered to collect information on demographic characteristics and reported exposures. Odds ratios were calculated for risk of colorectal cancer in relation to quartiles of urinary 1-OHPG concentration. Potential determinants of natural log-transformed urinary 1-OHPG concentration were evaluated among a combined sample of controls from this study and another nested case–control study in the SWHS (Ntotal=652).ResultsNo statistically significant differences in risk of colorectal cancer by urinary 1-OHPG levels were observed. Among controls, the median (interquartile range) urinary 1-OHPG concentration was 2.01 pmol/mL (0.95-4.09). Active and passive smoking, using coal as a cooking fuel, eating foods that were cooked well done, and recent consumption of fried dough (e.g., yóutiáo) were associated with elevated levels of 1-OHPG, though only active smoking and fried dough consumption achieved statistical significance in multivariate analyses.ConclusionsThis study does not provide evidence of an association between urinary levels of 1-OHPG and risk of colorectal cancer among women. Several environmental and dietary sources of PAH exposure were identified. Overall, the levels of 1-OHPG in this population of predominantly non-smoking women were considerably higher than levels typically observed among non-smokers in Europe, North America, and other developed regions.

Prospective evaluation of type 2 diabetes mellitus on the risk of primary liver cancer in Chinese men and women

BackgroundNo prospective study has investigated the relationship between type 2 diabetes mellitus (T2DM) and the risk of primary liver cancer (PLC) in mainland China, and little is known about the effect of diabetes duration on PLC risk. DesignData from two population-based cohorts (the Shanghai Men's Health Study, SMHS, 2002–2006 and the Shanghai Women's Health Study, SWHS, 1996–2000) were thus used to assess the associations among T2DM, diabetes duration and PLC risk in Chinese population. ResultsDuring follow-up through 2009, 344 incident PLC cases were identified among 60 183 men and 73 105 women. T2DM is significantly associated with the increased risk of PLC in both men [hazard ratio (HR) = 1.63, 95% confidence interval (CI) 1.06–2.51] and women (HR = 1.64, 95% CI 1.03–2.61). The highest risk of incident liver cancer was observed in the first 5 years after diabetes diagnosis, and decreased substantially with the prolonged diabetes duration (Ptrend < 0.001). No synergistic interaction in the development of PLC was found between diabetes and other known risk factors. ConclusionsT2DM is associated with the increased risk of subsequent liver cancer within 5 years after diagnosis in Chinese population, suggesting that hyperinsulinaemia rather than hyperglycaemia is more likely to be a primary mediator for this association.

Abstract 3629: Household ventilation, cooking fuels and oils, and lung cancer risk in a prospective cohort of non-smoking Chinese women.

Abstract Lung cancer incidence has been on the rise in less-developed countries. Indoor air pollution caused by poor ventilation, burning of solid fuels, and cooking oils has been associated with lung cancer risk in developing poor and rural countries in many retrospective case-control studies. However, few studies have been conducted in more urban and more economically developed populations, even less in prospective studies. To assess the relationship of indoor air quality and risk of lung cancer in a modern population, a prospective cohort study was conducted in the Shanghai Women's Health Study. 73,442 women were followed through December 2009. A total of 469 lung cancer patients were diagnosed during the follow-up period, but after excluding ever smokers, 71,320 women in the cohort and 429 women with lung cancer were included in this analysis. Standardized and structured questionnaires were used to collect information on all household living and cooking practices: past three residences lived, cooking fuel utilized, cooking oil utilized, ventilation conditions, smoking patterns of family at home, and coworker smoking at work. Effect estimates for household ventilation conditions, cooking fuels, and cooking oils use for the risk of lung cancer are presented as hazard ratios (HR) with 95% confidence intervals (95% CI) from Cox proportional hazards regression. Ever having poor household ventilation was associated with a 61% increase in lung cancer risk (HR: 1.61; 95% CI: 1.19-2.18), and more than 20 years was associated with a 100% increase in risk (HR: 2.00; 95% CI: 1.32-3.01) compared to always having good ventilation. Ever use of coal with poor ventilation was associated with a 71% increased risk of lung cancer (HR: 1.71; 95% CI: 1.19-2.46), and more than 20 years of using coal with poor ventilation was associated with an 83% increase (HR: 1.83; 95% CI: 1.16-2.89) compared to gas users with good ventilation. There was some suggestion of lung cancer risk with vegetable oil use compared to soybean oil use, although the number of lung cancer cases was few and not statistically stable. In summary, this prospective cohort study of non-smoking Chinese women suggests that exposure to poor ventilation and poorly vented cooking coal increases the risk of lung cancer. These findings were consistent with past retrospective case-control studies and suggesting that past exposure to coal use with poorly ventilated conditions pose a health risk. These results suggest that current modern day cooking conditions, particularly in poorly ventilated homes, is still a public health issue. Citation Format: Christopher Kim, Yutang Gao, Yongbing Xiang, Francesco Barone-Adesi, Yawei Zhang, H. Dean Hosgood, Shuangge Ma, Xiao-ou Shu, Bu-Tian Ji, Wong-Ho Chow, Qiuyin Cai, Wei Zheng, Nathaniel Rothman, Qing Lan. Household ventilation, cooking fuels and oils, and lung cancer risk in a prospective cohort of non-smoking Chinese women. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3629. doi:10.1158/1538-7445.AM2013-3629

Longer Telomere Length in Peripheral White Blood Cells Is Associated with Risk of Lung Cancer and the rs2736100 (CLPTM1L-TERT) Polymorphism in a Prospective Cohort Study among Women in China

A recent genome-wide association study of lung cancer among never-smoking females in Asia demonstrated that the rs2736100 polymorphism in the TERT-CLPTM1L locus on chromosome 5p15.33 was strongly and significantly associated with risk of adenocarcinoma of the lung. The telomerase gene TERT is a reverse transcriptase that is critical for telomere replication and stabilization by controlling telomere length. We previously found that longer telomere length measured in peripheral white blood cell DNA was associated with increased risk of lung cancer in a prospective cohort study of smoking males in Finland. To follow up on this finding, we carried out a nested case-control study of 215 female lung cancer cases and 215 female controls, 94% of whom were never-smokers, in the prospective Shanghai Women’s Health Study cohort. There was a dose-response relationship between tertiles of telomere length and risk of lung cancer (odds ratio (OR), 95% confidence interval [CI]: 1.0, 1.4 [0.8–2.5], and 2.2 [1.2–4.0], respectively; P trend = 0.003). Further, the association was unchanged by the length of time from blood collection to case diagnosis. In addition, the rs2736100 G allele, which we previously have shown to be associated with risk of lung cancer in this cohort, was significantly associated with longer telomere length in these same study subjects (P trend = 0.030). Our findings suggest that individuals with longer telomere length in peripheral white blood cells may have an increased risk of lung cancer, but require replication in additional prospective cohorts and populations.

Prediagnosis Soy Food Consumption and Lung Cancer Survival in Women

We recently reported an inverse association between soy food intake and lung cancer risk among nonsmoking women. The effect size for aggressive lung cancers was larger than that observed for other types of lung cancer. Therefore, we hypothesized that soy consumption may favorably affect the overall survival of patients with lung cancer. This analysis included 444 women with incident lung cancer identified from the Shanghai Women's Health Study. Prediagnosis soy food intake was assessed at enrollment and reassessed 2 years later. Proportional hazards models were used to evaluate the association between soy food intake and overall survival. Of the 444 patients with lung cancer, 318 died during follow-up. Initial analyses including all patients showed that higher intake of soy food was associated with better overall survival after adjusting for demographic and lifestyle characteristics and other nonclinical factors. Larger effect sizes for the association were found after additional adjustment for tumor stage and treatment in analyses including 301 patients with data available on these clinical factors. Compared with the median intake of soy food, fully adjusted hazard ratios for total mortality associated with the 10th, 30th, 70th, and 90th percentiles of intake were 1.81 (95% CI, 1.26 to 2.59), 1.25 (95% CI, 1.09 to 1.42), 0.88 (95% CI, 0.80 to 0.97), and 0.89 (95% CI, 0.68 to 1.16), respectively. Similar inverse associations were observed for dietary isoflavone intake. This study suggests, to the best of our knowledge for the first time, that, among women with lung cancer, prediagnosis intake of soy food is associated with better overall survival.

Association of Leukocyte Telomere Length With Breast Cancer Risk: Nested Case-Control Findings From the Shanghai Women's Health Study

Telomeres are specialized chromatin structures essential for the maintenance of chromosomal integrity and stability. Telomere shortening has been linked to multiple aging-related diseases, including cancer. Evidence associating telomere length with breast cancer risk-most of which has been from retrospective case-control studies-is conflicting. We conducted a nested case-control study based on the Shanghai Women's Health Study (1997-2009) in which we evaluated the association of telomere length and breast cancer risk using peripheral blood samples collected before cancer diagnosis (601 cases and 695 controls). We used monochrome multiplex quantitative polymerase chain reaction to measure relative telomere length. Multiple logistic regressions were used to derive adjusted odds ratios with 95% confidence intervals as the measure of association. Telomere length was inversely correlated with age (r = -0.22). Women with moderately long telomeres (those in the fourth quintile) had the lowest breast cancer risk. Risk increased in a dose-response manner with decreasing quintile of telomere length; odds ratios were 1.39 (95% confidence interval (CI): 0.95, 2.04), 1.79 (95% CI: 1.17, 2.75), and 2.39 (95% CI: 1.45, 3.92), respectively, for the third, second, and first quintiles compared with the fourth quintile. A slightly elevated risk of breast cancer (odds ratio = 1.35, 95% CI: 0.90, 2.04), although one that was not statistically significant, was found in the top quintile (longest telomeres). Our results support the hypothesis that telomere shortening is associated with increased risk of breast cancer and suggest a possible elevated risk associated with long telomeres.

T'ai chi as exercise among middle-aged and elderly Chinese in urban China.

T'ai chi is a form of mind-body practice used as exercise in China, though limited data are available on characteristics of t'ai chi users and factors associated with practice. Characteristics of and factors associated with t'ai chi practice among middle-aged and elder Chinese in Shanghai China were analyzed utilizing baseline data from the Shanghai Women's Health Study and Shanghai Men's Health Study. Logistic regression modeling was used to identify independent factors associated with the practice of t'ai chi among men and women. T'ai chi is the most common form of regular exercise in Shanghai China among middle-aged and elderly persons (22%), including among women (28%) and men (15%). Other popular forms of exercise were walking (7%), dancing (4%), and jogging (3%). A majority of adults who practiced t'ai chi used it as their exclusive type of exercise (69%). Overall, t'ai chi practitioners as compared to nonpractitioners were more likely women, older, more educated, retired versus still working, and more likely to report chronic medical conditions including pulmonary, gastrointestinal, and cardiovascular conditions. T'ai chi activity was associated with other health behaviors including nonsmoking, consuming ginseng, and participating in other forms of physical exercise. T'ai chi is the predominant form of exercise among middle-aged and elderly Chinese in urban China, particularly among those with older age and chronic medical diseases. Future research is needed to see whether t'ai chi has similar or different benefits than conventional forms of exercise such as walking and jogging.

Calcium Intake and Lung Cancer Risk Among Female Nonsmokers: A Report from the Shanghai Women's Health 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 nonsmokers. 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 nonsmokers 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/d, 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. Our study provides some of the first evidence suggesting a possible role for increasing dietary calcium intake in lung cancer prevention among female nonsmokers, especially in populations with relatively low calcium intake.

Dietary glycemic load, glycemic index, and carbohydrates on the risk of primary liver cancer among Chinese women and men

Dietary glycemic index (GI) and glycemic load (GL) typically have a positive relationship with obesity and diabetes, which are risk factors for liver cancer. However, studies on their association with liver cancer have yielded inconsistent results. Therefore, we assessed the association of GI, GL, and carbohydrates with liver cancer risk. A total of 72 966 women and 60 207 men from the Shanghai Women's Health Study (SWHS) and the Shanghai Men's Health Study (SMHS) were included for analysis. Food frequency questionnaire (FFQ) data were used to calculate daily dietary GI, GL, and carbohydrate intake. These values were energy adjusted and categorized into quintiles. The hazard ratios (HRs) and 95% confidence intervals (CI) were calculated with adjustment for potential confounders. After a median follow-up time of 11.2 years for the SWHS and 5.3 years for the SMHS, 139 and 208 incident liver cancer cases were identified in the SWHS and SMHS, respectively. In multivariable Cox regression models, no statistically significant trends by quintile of GI, GL, or carbohydrate intake were observed. Stratification by chronic liver disease/hepatitis, diabetes, or body mass index (BMI) did not alter the findings. There is little evidence that dietary GI, GL, or carbohydrates affect the incidence of liver cancer in this Asian population.

Prospective cohort study of tea consumption and risk of digestive system cancers: results from the Shanghai Women's Health Study

Data from in vitro and animal studies support a protective role for tea in the etiology of digestive system cancers; however, results from prospective cohort studies have been inconsistent. In addition, to our knowledge, no study has investigated the association of tea consumption with the incidence of all digestive system cancers in Chinese women. We investigated the association of regular tea intake (≥3 times/wk for >6 mo) with risk of digestive system cancers. We used the Shanghai Women's Health Study, a population-based prospective cohort study of middle-aged and older Chinese women who were recruited in 1996-2000. Adjusted HRs and associated 95% CIs were derived from Cox regression models. After a mean follow-up of 11 y, 1255 digestive system cancers occurred (stomach, esophagus, colorectal, liver, pancreas, and gallbladder/bile duct cancers) in 69,310 nonsmoking and non-alcohol-drinking women. In comparison with women who never drank tea, regular tea intake (mostly green tea) was associated with reduced risk of all digestive system cancers combined (HR: 0.86; 95% CI: 0.74, 0.98), and the reduction in risk increased as the amount and years of tea consumption increased (P-trend = 0.01 and P-trend < 0.01, respectively). For example, women who consumed ≥150 g tea/mo (∼2-3 cups/d) had a 21% reduced risk of digestive system cancers combined (HR: 0.79; 95% CI: 0.63, 0.99). The inverse association was found primarily for colorectal and stomach/esophageal cancers. In this large prospective cohort study, tea consumption was associated with reduced risk of colorectal and stomach/esophageal cancers in Chinese women.

Soy food intake and risk of lung cancer: evidence from the Shanghai Women's Health Study and a meta-analysis.

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 (P(trend) = 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 (P(interaction) = 0.01) and for aggressive lung cancer as defined by length of survival (<12 months vs. ≥12 months; P(heterogeneity) = 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.

Dietary B vitamin and methionine intakes and lung cancer risk among female never smokers in 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.

Association of Leukocyte Telomere Length with Colorectal Cancer Risk: Nested Case–Control Findings from the Shanghai Women's Health Study

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 about 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 before 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 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-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. 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.

Body weight, fat distribution and colorectal cancer risk: a report from cohort studies of 134 255 Chinese men and women

OBJECTIVETo evaluate the association of body size and fat distribution with risk of colorectal cancer (CRC) in Chinese men and women.DESIGNPopulation-based, prospective cohort study.SUBJECTSThe analysis included 134 255 Chinese adults enrolled in the Shanghai Women’s Health Study and the Shanghai Men’s Health Study, with an average follow-up of 11.0 and 5.5 years, respectively.MEASUREMENTSWaist circumference (WC), body mass index (BMI) and waist-to-hip ratio (WHR) were measured by trained interviewers at baseline. Multivariable Cox models were used to calculate adjusted hazard ratios (HRs) for incident CRC.RESULTSA total of 935 incident CRC cases were identified. Both measures of general adiposity (measured by BMI) and central adiposity (measured by WHR and WC) were significantly associated with increased risk of colon cancer in men but not in women. Multivariable adjusted HRs for colon cancer in men in the highest compared with the lowest quintiles were 2.15 (95% CI: 1.35-3.43; P for trend = 0.0006) for BMI, 1.97 (95% CI: 1.19-3.24; P for trend = 0.0004) for WHR and 2.00 (95% CI: 1.21-3.29; P for trend = 0.0002) for WC. The BMI-associated risk was attenuated in analyses stratified by WHR, while the WHR-associated risk remained significant in the high BMI stratum (HR for comparison of extreme tertiles of WHR: 3.38, 95% CI: 1.47-7.75; P for trend =0.0002). None of these anthropometric measures were significantly associated with rectal cancer.CONCLUSIONObesity, particularly central obesity, was associated with increased risk of colon cancer in men.

Nightshift work job exposure matrices and urinary 6-sulfatoxymelatonin levels among healthy Chinese women.

Six-sulfatoxymelatonin (aMT6s) is a primary urinary metabolite of melatonin. We examined the association between aMT6s levels and shift work estimated by a job exposure matrix (JEM) among healthy participants of the Shanghai Women's Health Study. Creatinine-adjusted aMT6s levels were measured in the urine samples of 300 women and related to JEM shift work categories. Adjusted geometric means of aMT6s levels from urine samples collected before 08:00 hours were lower among persons holding nighttime shift work jobs. The adjusted aMT6s levels (ng/mg creatinine) were 8.36 [95% confidence intervals (95% CI) 4.47-15.6], 6.37 (95% CI 3.53-11.5), 6.20 (95% CI 3.33-11.5), 3.81 (95% CI 2.02-7.19), and 3.70 (95% CI 1.92-7.11) from the lowest (never held a shift work job) to the highest (current job likely involved all-night shift work) shift work JEM scores (P=0.05). Our results indicate that nightshift work JEM scores were significantly and inversely associated with aMT6s levels in early morning spot urine samples collected between 07:00-08:00 hours.

Sleep duration and its correlates in middle-aged and elderly Chinese women: The Shanghai Women’s Health Study

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 h/day, 11.5% slept 5h or less, and 8.7% slept 9h 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 7 h/day (6.5-7.4h/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.

Major metabolite of F2-isoprostane in urine may be a more sensitive biomarker of oxidative stress than isoprostane itself

There is limited literature on the contributors to isoprostane metabolite 2,3-dinor-5,6-dihydro-15-F(2t)-isoprostane (15-F(2t)-IsoP-M) compared with F(2)-isoprostanes (F(2)-IsoPs) as an oxidative stress biomarker. The objective of this study was to investigate whether plasma concentrations of antioxidants, urinary excretion rates of polyphenols, and antioxidants in food and dietary supplements are attributable to both urinary F(2)-IsoP and 15-F(2t)-IsoP-M concentrations. Dietary intake information and blood and urine samples were obtained from 845 healthy middle-aged and elderly female participants of the Shanghai Women's Health Study. Urinary isoprostanes (F(2)-IsoPs and 15-F(2t)-IsoP-M) were measured and adjusted for creatinine concentrations. Urinary 15-F(2t)-IsoP-M and F(2)-IsoP concentrations were lower in subjects who used a multivitamin. Lower F(2)-IsoP concentrations were observed in ginseng users, whereas lower concentrations of 15-F(2t)-IsoP-M were shown in subjects who used a vitamin E supplement. Plasma concentrations of several antioxidants (ie, β-carotenes, both trans and cis β-carotenes, lycopene other than trans, 5-cis and 7-cis isomers, cis anhydrolutein, and cis β-cryptoxanthin) were inversely associated with 15-F(2t)-IsoP-M but not with F(2)-IsoPs, whereas β-, γ-, and δ-tocopherols were positively associated with 15-F(2t)-IsoP-M but not with F(2)-IsoPs. Urinary polyphenol quercetin was positively associated with both F(2)-IsoPs and 15-F(2t)-IsoP-M. The results suggest that the F(2)-IsoP major metabolite 15-F(2t)-IsoP-M may be a more sensitive marker of endogenous oxidative stress status than are F(2)-IsoPs in the assessment of effects of antioxidants on age-related diseases.

Vitamin intake and liver cancer risk: a report from two cohort studies in China.

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.

Thyroid cancer risk and dietary nitrate and nitrite intake in the Shanghai women's health study.

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 relative 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 [RR(Q4) = 0.93; 95% confidence interval (CI): 0.42-2.07; p for trend = 0.40]. Compared to the lowest quartile, women with the highest dietary nitrite intake had about a twofold risk of thyroid cancer (RR(Q4) = 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 (RR(Q4) = 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.

Abstract 626: Dietary glycemic load, glycemic index and risk of primary liver cancer: Results from the Shanghai women's and men's health studies

Abstract Introduction Dietary glycemic index (GI) and glycemic load (GL) have been observed to have a positive relationship with obesity and diabetes which are risk factors for liver cancer. However, studies assessing the association between GI, GL and liver cancer have yielded inconsistent results. We evaluated the association of GI and GL with liver cancer using data from two prospective cohort studies, the Shanghai Women's Health Study (SWHS) and the Shanghai Men's Health Study (SMHS). Methods The study population consisted of 72,906 women from SWHS and 60,203 men from the SMHS who had not been previously diagnosed with cancer, did not have extreme total energy intake as assessed by a food frequency questionnaire (FFQ) and had complete data on all covariates of interest. Subject recruitment for the SWHS began in 1996 and for the SMHS began in 2002. Outcome follow-up data through December 31, 2009 from both cohorts were used in the current analysis. At baseline, a validated FFQ was administered and daily dietary GI and GL were calculated for each cohort member. These values were energy adjusted using the residuals method and categorized into quintiles. Confounders were assessed using data from the baseline questionnaire. Hazard ratios and 95% confidence intervals were calculated for the association between GI/GL and liver cancer incidence with adjustment for potential confounders. Results After a median follow-up of 11.2 and 5.3 years for the SWHS and SMHS, respectively, 346 incident liver cancer (ICD-9: 155) were identified. Women in the upper quintiles of GL intake were more likely to be older, have less education, have lower annual family incomes, be smokers, be post-menopausal, and were less likely to exercise, consume alcohol or have a history of diabetes or hepatitis. Men in the upper quintiles of GL intake were more likely to have less education, have lower annual per capita family incomes, and were less likely to exercise, to consume alcohol or have a history of diabetes. After adjustment for all confounders, no statistically significant trends were observed for men or women for the quintile of intake of GI or GL with the incidence of liver cancer (SWHS: GL p trend = 0.67, GI p trend = 0.11; SMHS: GL p trend = 0.64, GI p trend = 0.29). Similarly, no statistically significant trends were observed when the models were stratified by chronic hepatitis status (yes or no). Conclusions There is little evidence that GI or GL affect the incidence of liver cancer in this population. Further research about other modifiable risk factors for liver cancer is warranted. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 626. doi:1538-7445.AM2012-626