Y. T. Gao

Gallstones and the risk of biliary tract cancer: a population-based study in China.

We conducted a population-based study of 627 patients with biliary tract cancers (368 of gallbladder, 191 bile duct, and 68 ampulla of Vater), 1037 with biliary stones, and 959 healthy controls randomly selected from the Shanghai population, all personally interviewed. Gallstone status was based on information from self-reports, imaging procedures, surgical notes, and medical records. Among controls, a transabdominal ultrasound was performed to detect asymptomatic gallstones. Gallstones removed from cancer cases and gallstone patients were classified by size, weight, colour, pattern, and content of cholesterol, bilirubin, and bile acids. Of the cancer patients, 69% had gallstones compared with 23% of the population controls. Compared with subjects without gallstones, odds ratios associated with gallstones were 23.8 (95% confidence interval (CI), 17.0–33.4), 8.0 (95% CI 5.6–11.4), and 4.2 (95% CI 2.5–7.0) for cancers of the gallbladder, extrahepatic bile ducts, and ampulla of Vater, respectively, persisting when restricted to those with gallstones at least 10 years prior to cancer. Biliary cancer risks were higher among subjects with both gallstones and self-reported cholecystitis, particularly for gallbladder cancer (OR=34.3, 95% CI 19.9–59.2). Subjects with bile duct cancer were more likely to have pigment stones, and with gallbladder cancer to have cholesterol stones (P<0.001). Gallstone weight in gallbladder cancer was significantly higher than in gallstone patients (4.9 vs 2.8 grams; P=0.001). We estimate that in Shanghai 80% (95% CI 75–84%), 59% (56–61%), and 41% (29–59%) of gallbladder, bile duct, and ampulla of Vater cancers, respectively, could be attributed to gallstones.

Duration of breast-feeding and the incidence of type 2 diabetes mellitus in the Shanghai Women's Health Study

Aims/hypothesisThe aim of this study was to examine the association between lifetime breast-feeding and the incidence of type 2 diabetes mellitus in a large population-based cohort study of middle-aged women.MethodsThis was a prospective study of 62,095 middle-aged parous women in Shanghai, China, who had no prior history of type 2 diabetes mellitus, cancer or cardiovascular disease at study recruitment. Breast-feeding history, dietary intake, physical activity and anthropometric measurements were assessed by in-person interviews. The Cox regression model was employed to evaluate the association between breast-feeding and the risk of type 2 diabetes mellitus.ResultsAfter 4.6xa0years of follow-up, 1,561 women were diagnosed with type 2 diabetes mellitus. Women who had breastfed their children tended to have a lower risk of diabetes mellitus than those who had never breastfed [relative risk (RR)u2009=u20090.88; 95% CI, 0.76–1.02; pu2009=u20090.08]. Increasing duration of breast-feeding was associated with a reduced risk of type 2 diabetes mellitus. The fully adjusted RRs for lifetime breast-feeding duration were 1.00, 0.88, 0.89, 0.88, 0.75 and 0.68 (p trendu2009=u20090.01) for 0, >0 to 0.99, >0.99 to 1.99, >1.99 to 2.99, >2.99 to 3.99 and ≥4xa0years in analyses adjusted for age, daily energy intake, BMI, WHR, smoking, alcohol intake, physical activity, occupation, income level, education level, number of live births and presence of hypertension at baseline.Conclusions/interpretationBreast-feeding may protect parous women from developing type 2 diabetes mellitus later in life.

Body size and the risk of biliary tract cancer: a population-based study in China

Though obesity is an established risk factor for gall bladder cancer, its role in cancers of the extrahepatic bile ducts and ampulla of Vater is less clear, as also is the role of abdominal obesity. In a population-based case–control study of biliary tract cancer in Shanghai, China, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for biliary tract cancer in relation to anthropometric measures, including body mass index (BMI) at various ages and waist-to-hip ratio (WHR), adjusting for age, sex, and education. The study included 627 patients with biliary tract cancer (368 gall bladder, 191 bile duct, 68 ampulla of Vater) and 959 healthy subjects randomly selected from the population. A higher BMI at all ages, including early adulthood (ages 20–29 years), and a greater WHR were associated with an increased risk of gall bladder cancer. A high usual adult BMI (⩾25) was associated with a 1.6-fold risk of gall bladder cancer (95% CI 1.2–2.1, P for trend <0.001). Among subjects without gallstones, BMI was also positively associated with gall bladder cancer risk. Regardless of BMI levels, increasing WHR was associated with an excess risk of gall bladder cancer risk, with those having a high BMI (⩾25) and a high WHR (>0.90) having the highest risk of gall bladder cancer (OR=12.6, 95% CI 4.8–33.2), relative to those with a low BMI and WHR. We found no clear risk patterns for cancers of the bile duct and ampulla of Vater. These results suggest that both overall and abdominal obesity, including obesity in early adulthood, are associated with an increased risk of gall bladder cancer. The increasing prevalence of obesity and cholesterol stones in Shanghai seems at least partly responsible for the rising incidence of gall bladder cancer in Shanghai.

Physical activity and breast cancer risk in Chinese women

Background:The influence of different types and intensities of physical activity on risk for breast cancer is unclear.Methods:In a prospective cohort of 73u2009049 Chinese women (40–70 years), who had worked outside the home, we studied breast cancer risk in relation to specific types of self-reported and work history-related physical activity, including adolescent and adult exercise and household activity and walking and cycling for transportation. Occupational sitting time and physical activity energy expenditure were assigned based on lifetime occupational histories.Results:In all, 717 incident breast cancer cases were diagnosed. Breast cancer risk was lower for women in the lowest quartile of average occupational sitting time and in the highest quartile of average occupational energy expenditure (adjusted hazard ratio (HR): 0.81 and 0.73, respectively, P⩽0.05). Adult exercise at or above the recommended level (8 metabolic equivalent (MET) h per week per year) was associated with lower risk (adjusted HR: 0.73, P<0.05) in post-menopausal women. Analysis of joint effects showed that having both an active job and exercise participation did not confer an additional benefit. Other common daily activities were not associated with lower risk.Interpretation:These findings suggest that both exercise and occupational activity are associated with lower breast cancer risk, which supports current health promotion campaigns promoting exercise.

Anthropometric measures and epithelial ovarian cancer risk among Chinese women: results from the Shanghai Women’s Health Study

Background:Studies of anthropometric measures and ovarian cancer risk have predominantly included women of European descent with mixed findings.Methods:Data from the prospective Shanghai Women’s Health Study (SWHS) were used to evaluate associations between anthropometric measures and risk of epithelial ovarian cancer (EOC). Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by Cox proportional hazards regression.Results:A total of 152 EOC cases occurred among 70u2009258 women. Increasing quartiles of weight, hip circumference, and weight gain during adulthood were associated with significantly increased EOC risks. Body mass index (BMI) was also associated; overweight (25⩽BMI<29.99) and obese women (BMI⩾30.0) had significantly increased risks (HR: 1.49, 95% CI: 1.05, 2.13, and HR: 2.42, 95% CI: 1.37, 4.28, respectively). No significant associations were observed for height, waist circumference, waist-to-hip ratio (WHR), and waist-to-height ratio (WHER).Conclusion:Results from this large prospective study of Chinese women support the hypothesis that general adiposity contributes to the aetiology of ovarian cancer.

Declining incidence is greater for esophageal than gastric cancer in Shanghai, People's Republic of China.

Temporal trends in the incidence of esophageal and gastric cancers during 1972 to 1989 were addressed in urban Shanghai, the location of Chinas longest standing cancer registry. Over the 18 year study period, esophageal cancer rates decreased more than 50% from 28.8/100,000 person-years in 1972-74 to 13.3/100,000 in 1987-89 among men and from 11.3/100,000 to 5.4/100,000 among women. Reductions were apparent in each age group, but most pronounced among younger generations, with more than a 75% decline in incidence among those under age 55 years. The incidence rate for stomach cancer among men decreased 20% from 62.0/100,000 in 1972-74 to 50.1/100,000 in 1987-89. The reduction among women, however, was minor, from 23.9/100,000 to 23.2/100,000. The patterns varied by age, with declines among persons 45-64 years and increases among those in older and younger age groups. The determinants of these trends are not clear, but appear related in part to dietary changes.

CYP19A1 genetic polymorphisms may be associated with obesity-related phenotypes in Chinese women.

Object:To examine the relationship between genetic polymorphisms of the CYP19A1 gene and obesity-related phenotypes, body mass index (BMI) and waist-to-hip ratio (WHR).Subjects:In total, 1241 Chinese women, who were recruited as community controls for a population-based case–control study of breast cancer.Methods:Nineteen haplotype tagging single nucleotide polymorphisms (htSNPs) in four haplotype blocks were genotyped.Results:Significant associations were observed for WHR at three SNPs that are located in haplotype block 1, including rs2445765, rs1004984 and rs1902584 (P=0.05, 0.04 and 0.01, respectively). Women, particularly premenopausal women, who carried the minor allele at any of these SNPs, had higher WHR than those without it. Of these three SNPs, the strongest association was observed at rs1902584, which is the closest to Promoter I.4, the major promoter for adipose tissue. Haplotype analyses indicated an association between the haplotype TCCAT in block 1 and WHR with a P-value of 0.02.Conclusion:These results suggested that CYP19A1 genetic polymorphisms may be associated with the risk of obesity among Chinese women, especially among premenopausal women.The CYP19A1 protein (aromatase) plays a critical role in estrogen biosynthesis and thus affects body fat distribution and regulation.

Impacts of weight change on prehypertension in middle-aged and elderly women

Background:Individuals with prehypertension, a new blood pressure category defined as systolic blood pressure of 120–139u2009mm Hg and/or diastolic blood pressure of 80–89u2009mm Hg, are at an increased risk for heart diseases and are strongly recommended to practice lifestyle changes, including weight control. Data on impacts of long-term weight change on prehypertension are sparse.Objective:To evaluate the association between weight change since age 20 and prehypertension risk.Methods:In this cross-sectional analysis of 36u2009075 non-hypertensive women aged 40–70 years, information on weight history was collected at enrollment in the Shanghai Womens Health Study; blood pressures were measured 2–3 years later by medical professionals. The odds ratios (ORs) of prehypertension were calculated for women who gained or lost weight since age 20 compared with those with stable weight (gain or loss <5u2009kg), adjusting for age, lifestyle factors, sodium intake and body mass index at age 20.Results:A total of 47% of the study participants (n=16u2009981) had prehypertension. For a 6- to 10-kg gain, the OR (95% CI) was 1.36 (1.28–1.45); for 11- to 15-kg gain, 1.64 (1.54–1.75); for 16- to 20-kg gain, 2.32 (2.14–2.51); for 21- to 25-kg gain, 2.91 (2.60–3.26); and for a gain >25u2009kg; 3.65 (3.13–4.26). While for a 6- to 10-kg loss and a loss >10u2009kg, the respective ORs were 0.76 (0.67–0.87) and 0.47 (0.38–0.59). The increase in prehypertension risk associated with each 1-kg gain was similar to that associated with a 1-year increase in age. Although weight gain during early adulthood appeared to have a more pronounced effect on the risk of prehypertension, weight gain later in life also contributed significantly to an elevated risk.Conclusion:Weight gain since age 20 substantially increases risk for prehypertension in non-hypertensive individuals, while weight loss significantly lowers the risk, emphasizing the importance of weight control throughout adulthood in preventing hypertension.

Identification of new susceptibility loci for gastric non-cardia adenocarcinoma: pooled results from two Chinese genome-wide association studies

Objective Although several genome-wide association studies (GWAS) of non-cardia gastric cancer have been published, more novel association signals could be exploited by combining individual studies together, which will further elucidate the genetic susceptibility of non-cardia gastric cancer. Design We conducted a meta-analysis of two published Chinese GWAS studies (2031 non-cardia gastric cancer cases and 4970 cancer-free controls) and followed by genotyping of additional 3564 cases and 4637 controls in two stages. Results The overall meta-analysis revealed two new association signals. The first was a novel locus at 5q14.3 and marked by rs7712641 (per-allele OR=0.84, 95% CI 0.80 to 0.88; p=1.21×10−11). This single-nucleotide polymorphism (SNP) marker maps to the intron of the long non-coding RNA, lnc-POLR3G-4 (XLOC_004464), which we observed has lower expression in non-cardia gastric tumour compared with matched normal tissue (Pwilcoxon signed-rank=7.20×10−4). We also identified a new signal at the 1q22 locus, rs80142782 (per-allele OR=0.62; 95% CI 0.56 to 0.69; p=1.71×10−19), which was independent of the previously reported SNP at the same locus, rs4072037 (per-allele OR=0.74; 95% CI 0.69 to 0.79; p=6.28×10−17). Analysis of the new SNP conditioned on the known SNP showed that the new SNP remained genome-wide significant (Pconditional=3.47×10−8). Interestingly, rs80142782 has a minor allele frequency of 0.05 in East Asians but is monomorphic in both European and African populations. Conclusion These findings add new evidence for inherited genetic susceptibility to non-cardia gastric cancer and provide further clues to its aetiology in the Han Chinese population.

Reproductive factors and risks of biliary tract cancers and stones: A population-based study in Shanghai, China

Background:Parity has been linked to gallbladder cancer and gallstones, but the effects of other reproductive factors are less clear.Methods:We examined 361 incident biliary tract cancer cases, 647 biliary stone cases, and 586 healthy women in a population-based study in Shanghai.Results:The effects of parity (odds ratios, OR⩾3 vs 1 child=2.0, 95% confidence interval (CI) 0.7–5.1), younger age at first birth (ORper 1-year decrease=1.2, 95% CI 0.99–1.6), and older age at menarche (ORper 1-year increase=1.4, 95% CI 1.1–1.8) on gallbladder cancer risk were more pronounced among women with stones, but the interactions were not significant.Conclusion:Our results provide support for high parity, younger age at first birth, and late age at menarche in the development of gallbladder cancer, particularly among women with biliary stones.