Honglan Li

Adolescent and adult soy food intake and breast cancer risk: results from the Shanghai Women's Health Study

BACKGROUND Soy food is a rich source of isoflavones--a class of phytoestrogens that has both antiestrogenic and anticarcinogenic properties. OBJECTIVE The objective was to evaluate the association of adolescent and adult soy food intake with breast cancer risk in a cohort of 73,223 Chinese women who participated in the Shanghai Womens Health Study. DESIGN A validated food-frequency questionnaire was used to assess usual dietary intake during adulthood and adolescence. After a mean follow-up of 7.4 y, 592 incident cases of breast cancer were identified for longitudinal analyses by using Cox regressions. RESULTS Adult soy food consumption, measured either by soy protein or isoflavone intake, was inversely associated with the risk of premenopausal breast cancer, and the association was highly statistically significant (P for trend < 0.001). The multivariate-adjusted relative risks (RRs) for the upper intake quintile compared with the lowest quintile were 0.41 (95% CI: 0.25, 0.70) for soy protein intake and 0.44 (95% CI: 0.26, 0.73) for isoflavone intake. High intake of soy foods during adolescence was also associated with a reduced risk of premenopausal breast cancer (RR: 0.57; 95% CI: 0.34, 0.97). Women who consumed a high amount of soy foods consistently during adolescence and adulthood had a substantially reduced risk of breast cancer. No significant association with soy food consumption was found for postmenopausal breast cancer. CONCLUSION This large, population-based, prospective cohort study provides strong evidence of a protective effect of soy food intake against premenopausal breast cancer.

Dietary calcium and magnesium intakes and the risk of type 2 diabetes: the Shanghai Women's Health Study

BACKGROUND Diet plays a key role in the development of type 2 diabetes (T2D), but little is known about the contributions of specific nutrients in populations in which dietary patterns differ from Western populations. OBJECTIVE We examined associations between calcium and magnesium intakes and the risk of T2D in a Chinese population. DESIGN We used data from a population-based, prospective study of 64,191 women who were free of T2D or other chronic diseases at study recruitment and were living in urban Shanghai, China. Dietary intake, physical activity, and anthropometric measurements were assessed through in-person interviews. A Cox regression model was used to evaluate the association of the exposures under study with the risk of T2D. RESULTS An inverse association between calcium and magnesium intakes and T2D risk was observed. The relative risks for the lowest to the highest quintiles of calcium intake were 1.00, 0.82, 0.73, 0.67, and 0.74 (P for trend < 0.001), and for magnesium they were 1.00, 0.84, 0.84, 0.79, and 0.86 (P for trend < 0.001). Milk intake was also inversely associated with the risk of T2D. CONCLUSION Our data suggest that calcium and magnesium intakes may protect against the development of T2D in this population.

Cruciferous vegetables intake and the risk of colorectal cancer: a meta-analysis of observational studies

BACKGROUND Epidemiological studies have reported inconsistent associations between cruciferous vegetable (CV) intake and colorectal cancer (CRC) risk. To our knowledge, a comprehensive and quantitative assessment of the association between CV intake and CRC has not been reported. METHODS Relevant articles were identified by searching MEDLINE. We pooled the relative risks (RR) from individual studies using a random-effect model and carried out heterogeneity and publication bias analyses. RESULTS Twenty-four case-control and 11 prospective studies were included in our analysis. When all studies were pooled, we yielded a significantly inverse association between CV (RR: 0.82; 95% confidence interval 0.75-0.90) intake and CRC risk. Specific analysis for cabbage and broccoli yielded similar result. When separately analyzed, case-control studies of CV intake yield similar results, and the results from the prospective studies showed borderline statistical significance. Moreover, significant inverse associations were also observed in colon cancer and its distal subsite both among prospective and case-control studies. CONCLUSIONS Findings from this meta-analysis provide evidence that high intake of CV was inversely associated with the risk of CRC and colon cancer in humans. Further analysis on other specific CV, food preparation methods, stratified results by anatomic cancer site, and subsite of colon cancer should be extended in future study.

Genome-wide association analyses in east Asians identify new susceptibility loci for colorectal cancer

To identify new 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 association P values of 8.58 × 10−7 to 3.77 × 10−10 in the combined analysis of all east Asian samples. Three of the four were replicated in a study conducted in 26,060 individuals of European descent, with combined P values 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), derived from meta-analysis of data from both east Asian and European-ancestry populations. This study identified three new CRC susceptibility loci and provides additional insight into the genetics and biology of CRC.

Cruciferous vegetable consumption is associated with a reduced risk of total and cardiovascular disease mortality

BACKGROUND Asian populations habitually consume a large amount of cruciferous vegetables and other plant-based foods. Few epidemiologic investigations have evaluated the potential health effects of these foods in Asian populations. OBJECTIVE We aimed to examine the associations of cruciferous vegetables, noncruciferous vegetables, total vegetables, and total fruit intake with risk of all-cause and cause-specific mortality. DESIGN The analysis included 134,796 Chinese adults who participated in 2 population-based, prospective cohort studies: the Shanghai Womens Health Study and the Shanghai Mens Health Study. Dietary intakes were assessed at baseline through in-person interviews by using validated food-frequency questionnaires. Deaths were ascertained by biennial home visits and linkage with vital statistics registries. RESULTS We identified 3442 deaths among women during a mean follow-up of 10.2 y and 1951 deaths among men during a mean follow-up of 4.6 y. Overall, fruit and vegetable intake was inversely associated with risk of total mortality in both women and men, and a dose-response pattern was particularly evident for cruciferous vegetable intake. The pooled multivariate hazard ratios (95% CIs) for total mortality across increasing quintiles of intake were 1 (reference), 0.91 (0.84, 0.98), 0.88 (0.77, 1.00), 0.85 (0.76, 0.96), and 0.78 (0.71, 0.85) for cruciferous vegetables (P < 0.0001 for trend) and 0.88 (0.79, 0.97), 0.88 (0.79, 0.98), 0.76 (0.62, 0.92), and 0.84 (0.69, 1.00) for total vegetables (P = 0.03 for trend). The inverse associations were primarily related to cardiovascular disease mortality but not to cancer mortality. CONCLUSION Our findings support recommendations to increase consumption of vegetables, particularly cruciferous vegetables, and fruit to promote cardiovascular health and overall longevity.

Prospective Cohort Study of Green Tea Consumption and Colorectal Cancer Risk in Women

Tea and its constituents have shown anticarcinogenic activities in in vitro and animal studies. Epidemiologic studies, however, have been inconsistent. We prospectively evaluated the association between green tea consumption and colorectal cancer (CRC) risk in a cohort of 69,710 Chinese women aged 40 to 70 years. Information on tea consumption was assessed through in-person interviews at baseline and reassessed 2 to 3 years later in a follow-up survey. During 6 years of follow-up, 256 incident cases of CRC were identified. The multivariate relative risk of CRC was 0.63 (95% confidence interval, 0.45-0.88) for women who reported drinking green tea regularly at baseline compared with nonregular tea drinkers. A significant dose-response relationship was found for both the amount of tea consumed (P trend = 0.01) and duration in years of lifetime tea consumption (P trend = 0.006). The reduction in risk was most evident among those who consistently reported to drink tea regularly at both the baseline and follow-up surveys (relative risk, 0.43; 95% confidence interval, 0.24-0.77). The inverse association with regular tea drinking was observed for both colon and rectal cancers. This study suggests that regular consumption of green tea may reduce CRC risk in women. (Cancer Epidemiol Biomarkers Prev 2007;16(6):1219–23)

Oxidative Stress, Obesity, and Breast Cancer Risk: Results From the Shanghai Women's Health Study

PURPOSE Increased reactive oxygen species may exhaust the antioxidant capability of human defense systems, leading to oxidative stress and cancer development. Urinary F2-isoprostanes, secondary end products of lipid peroxidation, are more accurate markers of oxidative stress than other available biomarkers. No prospective study has investigated whether levels of 15-F(2t)-isoprostane (15-F(2t)-IsoP) and its metabolite 2,3-dinor-5,6-dihydro-15-F(2t)-IsoP (15-F(2t)-IsoPM) are related to breast cancer risk. PATIENTS AND METHODS We conducted a nested case-control study within the Shanghai Womens Health Study, a population-based cohort study of 74,942 Chinese women between 40 and 70 years of age. Prediagnostic urinary 15-F(2t)-IsoP and 15-F(2t)-IsoPM were measured by gas chromatography mass spectrometry for 436 breast cancer cases and 852 individually matched controls. RESULTS Urinary excretion of isoprostanes was not significantly different between cases and controls. However, among overweight women, levels of isoprostanes were positively associated with breast cancer risk, which became stronger with increasing body mass index (BMI). Among women with a BMI > or = 29, the odds ratio (OR) increased to 10.27 (95% CI, 2.41 to 43.80) for the highest compared with the lowest tertile of 15-F(2t)-IsoPM (P for trend = .003; P for interaction = .0004). In contrast, 15-F(2t)-IsoP and 15-F(2t)-IsoPM were inversely associated with breast cancer risk among nonoverweight women. Among women with a BMI < or = 23, breast cancer risk was reduced with increasing 15-F(2t)-IsoP levels in a dose-response manner (P for trend = .006), with an OR of 0.46 (95% CI, 0.26 to 0.80) for the highest tertile versus the lowest (P for interaction = .006). CONCLUSION Our results suggest that the role of oxidative stress in breast cancer development may depend on adiposity.

Dietary polyunsaturated fatty acids and breast cancer risk in Chinese women: A prospective cohort study

Breast cancer is the most common cancer in women. Controversy exists regarding the role of dietary fat in breast cancer etiology. We investigated the association of dietary polyunsaturated fatty acids (PUFAs) and the ratio of n‐6 PUFAs to marine‐derived n‐3 PUFAs with breast cancer risk in the Shanghai Womens Health Study, a prospective cohort study including 72,571 cancer‐free participants at baseline. Dietary fatty acid intake was determined using food frequency questionnaires. We used Cox proportional hazards analysis to estimate the relative risks (RRs) and 95% confidence intervals (CIs) for the association of breast cancer risk with dietary fatty acids consumption. In 583,998 person‐years of follow‐up, we identified 712 breast cancer cases. We found no association of breast cancer risk to dietary intake of linoleic acid, arachidonic acid, α‐linolenic acid or marine‐derived n‐3 PUFA. We found a statistically significant interaction between n‐6 PUFA intake, marine‐derived n‐3 PUFA intake and breast cancer risk (p = 0.008). Women with lower intake (the lowest tertile) of marine‐derived n‐3 PUFA and higher intake (the highest tertile) of n‐6 PUFA had an increase risk for breast cancer (RR = 2.06; 95% CI = 1.27–3.34) compared to women with higher intake (the highest tertile) of marine‐derived n‐3 PUFAs and lower intake (the lowest tertile) of n‐6 PUFAs after adjusting for potential confounders. The relative amounts of n‐6 PUFA to marine‐derived n‐3 PUFAs may be more important for breast cancer risk than individual dietary amounts of these fatty acids.

Environmental tobacco smoke and mortality in Chinese women who have never smoked : prospective cohort study

Abstract Objective To evaluate the association of environmental exposure to tobacco smoke from husbands and from work, as well as from family members in early life, with all cause mortality and mortality due to cancer or cardiovascular disease in Chinese women. Design Ongoing prospective cohort study in Shanghai, China. Participants Of 72 829 women who had never smoked, 65 180 women provided information on smoking by their husbands, and 66 520 women provided information on exposure to tobacco smoke at work and in early life from family members. Main outcome measures All cause mortality and cause specific mortality with the main focus on cancer and cardiovascular disease. Cumulative mortality according to exposure status, and hazard ratios. Results Exposure to tobacco smoke from husbands (mainly current exposure) was significantly associated with increased all cause mortality (hazard ratio 1.15, 95% confidence interval 1.01 to 1.31) and with increased mortality due to cardiovascular disease (1.37, 1.06 to 1.78). Exposure to tobacco smoke at work was associated with increased mortality due to cancer (1.19, 0.94 to 1.50), especially lung cancer (1.79, 1.09 to 2.93). Exposure in early life was associated with increased mortality due to cardiovascular disease (1.26, 0.94 to 1.69). Conclusions In Chinese women, exposure to environmental tobacco smoke is related to moderately increased risk of all cause mortality and mortality due to lung cancer and cardiovascular disease.

Fish, shellfish, and long-chain n−3 fatty acid consumption and risk of incident type 2 diabetes in middle-aged Chinese men and women

BACKGROUND Long-chain polyunsaturated n-3 (omega-3) fatty acids, found mainly in fish, have been postulated to reduce type 2 diabetes (T2D) risk. However, the role of long-chain n-3 fatty acids and fish intake in the development of T2D remains unresolved. OBJECTIVE We examined associations between fish, shellfish, and long-chain n-3 fatty acids and the risk of T2D in a middle-aged Chinese population. DESIGN This was a prospective population-based cohort study in 51,963 men and 64,193 women free of T2D, cardiovascular disease, and cancer at baseline with valid dietary information. Dietary intake, physical activity, and anthropometric measurements were collected. A Cox regression model was used to evaluate the association of fish, shellfish, and long-chain n-3 fatty acid (in g/d) with risk of T2D. RESULTS Fish, shellfish, and long-chain n-3 fatty acid intakes were inversely associated with T2D in women. The relative risks [RRs (95% CI)] for quintiles of fish intake were 1.00, 0.96 (0.86, 1.06), 0.84 (0.75, 0.94), 0.80 (0.71, 0.90), and 0.89 (0.78, 1.01) (P for trend = 0.003) and for shellfish were 1.00, 0.91 (0.82, 1.01), 0.79 (0.71, 0.89), 0.80 (0.71, 0.91), and 0.86 (0.76, 0.99) (P for trend = 0.006). In men, only the association between shellfish intake and T2D was significant. The RRs (95% CI) for quintiles of fish intake were 1.00, 0.92 (0.75, 1.13), 0.80 (0.65, 1.00), 0.89 (0.72, 1.11), and 0.94 (0.74, 1.17) (P for trend = 0.50) and for shellfish intake were 1.00, 0.93 (0.76, 1.12), 0.70 (0.56, 086), 0.66 (0.53, 0.82), and 0.82 (0.65, 1.02) (P for trend = 0.003). CONCLUSIONS An inverse association between fish and shellfish intake and T2D in women was found. No evidence of a detrimental effect of fish intake in this population was observed.