Tea consumption and risk of biliary tract cancers and gallstone disease: a population-based case-control study in Shanghai, China / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the relationship between tea consumption, biliary tract cancers and gallstone disease.</p><p><b>METHODS</b>A population-based case-control study was conducted in urban Shanghai from 1 June 1997 to 31 May 2001 involving interviews with 627 new cases of biliary tract cancers (including 368 cases of gallbladder cancer, 191 cases of extrahepatic bile duct cancer and 68 cases of cancer of the ampulla of Vater) aged 35 to 74 years and 959 population controls frequency-matched to cases by gender and age in five-year group. 1037 patients of gallstone disease were selected from the same hospital. All subjects were interviewed in person by trained interviewers by use of a structured questionnaire. Unconditional logistic regression analysis was used to calculate adjusted odds ratio (OR) and 95% confidence interval (CI).</p><p><b>RESULTS</b>Compared with tea non-drinkers, current tea consumption was inversely associated with risk of gallbladder cancer, extrahepatic bile duct cancer and gallstone disease among females with OR of 0.57 (95% CI: 0.34-0.96), 0.53 (95% CI: 0.27-1.03) and 0.71 (95% CI: 0.51-0.99), respectively. OR declined with younger age at initiation of tea drinking and with longer duration of tea consumption (P for trend < 0.05). Among males, the corresponding OR were mostly below one, although not statistically significant.</p><p><b>CONCLUSION</b>Tea consumption may decrease the risk of cancers of the gallbladder and extrahepatic bile duct among females. The protective effect appears to be independent of gallstone disease.</p>

A prospective cohort study on body mass index and mortality among middle-aged and elderly men in urban Shanghai / 中华流行病学杂志

<p><b>OBJECTIVE</b>To examine the association between body mass index (BMI) and mortality as well as the effect of age on it among middle-aged and elderly men in urban area of Shanghai.</p><p><b>METHODS</b>A total of 18,244 male subjects aged 45-64 years resided in urban area of Shanghai were enrolled in the study during January 1, 1986 through September 30, 1989, and were actively followed under annual visits. 'Cox proportional hazards model' was used to estimate the relative risks (RR).</p><p><b>RESULTS</b>By the end of the follow-up process in 2002, a total number of 235,762 person-years was accumulated in the cohort, with an average of 12.9 years per subject. A total number of 3365 deaths including 1381 from cancer and 1165 from cardio- and cerebro-vascular diseases (CVD), was identified during the follow-up period. Compared with those under normal BMI (BMI 18.5-23.9), the RRs of death for all causes of death among groups at low BMI (BMI < 18.5), overweight (BMI 24-27.9) and obesity (BMI > or = 28) were 1.20, 1.12 and 1.61, respectively, among non-smokers after adjustment for age, alcohol consumption and level of education. After excluding the numbers observed during the first 5 years of follow-up, the corresponding RRs became 1.01, 1.12, and 1.75, respectively. The risk of deaths from colon cancer or CVD increased along with the increase of BMI, while the risk of non-cancer and non-CVD deaths, mostly deaths from infectious diseases, increased significantly in the group of low BMI. Among those aged > or = 55 years at baseline survey, the risk for all causes of death increased more significantly with those having obesity. However, among those who were younger than 55 years of age, no significant correlation between BMI and overall mortality was noticed.</p><p><b>CONCLUSION</b>A positive relationship between obesity and total mortality was observed in the middle-aged and elderly men in urban Shanghai. The association was more obvious among the elderly while the risk of deaths from colon cancer or CVD rose along with the increase of BMI. The risk of death from infectious disease increased significantly in the group with low BMI.</p>

Methods for time trend analysis of cancer incidence rates / 中华流行病学杂志

<p><b>OBJECTIVE</b>To introduce statistical methods of time trend analysis on cancer rates.</p><p><b>METHODS</b>Cancer incidence data collected by the Shanghai Cancer Registry during 1991 to 1999 was used in the analysis to calculate the crude and age-adjusted rates, percent changes (PCs) and annual percent changes (APCs). APCs were estimated by a linear regression of the logarithm on the incidence rates during the nine years. It also introduced a method for partitioning a linear trend in age-adjusted rates into site-specific contributions to the overall floating trend. 95% confidence intervals for the APCs and contributions were described in the paper.</p><p><b>RESULTS</b>A decreasing rates were observed for cancers of stomach and esophagus among both men and women in urban Shanghai from 1991 to 1999. The increasing rates among men would include cancers of colon, rectum, gall bladder, pancreas, prostate, urinary bladder, kidney and leukemia. The rates of cancers among women increased for colon, rectum, lung, breast, gall bladder, endometrium, ovary, urinary bladder and kidney. The changes of above cancers over time were statistically significant (P < 0.05 or P < 0.01), but rates for other cancer sites changed little. The APCs (weighted method) and contributions for the cancers of stomach, esophagus, colon, rectum and prostate were -2.99% and -65.72%, -2.90% and -17.07%, 12.30% and 21.46%, 2.94% and 18.62%, and 3.11% and 15.09% among men, and -6.05% and -39.55%, -1.08% and -35.19%, 2.81% and 28.64%, and 3.69% and 15.70% for the cancers of stomach, esophagus, breast and colon in women, respectively.</p><p><b>CONCLUSION</b>APC, and related statistics could be used to describe and analyze the time trend of cancer rates rather than PC or/and graphical method alone.</p>

Cigarette smoking and cancer mortality: a prospective cohort study in urban males in Shanghai / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the association between cigarette smoking and cancer mortality in urban men in Shanghai and its impact when smoking habit changed during the follow-up period.</p><p><b>METHODS</b>A total of 18 244 male residents aged 45 to 64 years in urban Shanghai were enrolled in the study during January 1, 1986 through September 30, 1989, and was actively followed up on annual visits. Cox proportional hazards model was used to estimate relative risks (RR).</p><p><b>RESULTS</b>By the end of follow-up program in 2002, 235 762 person-years, averaged 12.9 years per subject in the cohort was reached. 3365 deaths including 1381 cancer deaths were registered during the follow-up period. The mortality rates for cancers of lung, stomach, liver, pancreas, esophagus, head and neck etc. increased significantly among smokers. Compared with data of nonsmokers at the baseline survey, the adjusted RR was 1.49 for all-causes mortality among current smokers at the baseline survey. After excluding subjects who changed their smoking habit during the follow-up period, the RR became 1.78 compared with lifelong-nonsmokers. The corresponding RRs rose from 2.05 to 2.58 for all cancer deaths and from 6.40 to 8.77 for lung cancer deaths. The age-adjusted all-causes and cancer death rates among current smokers at the baseline survey were 1695.6 and 782.0 per 100 000 person-years, respectively. After exclusion of those with smoking habit changed during the follow-up period, the rates among persistent smokers were 2353.7 and 1144.6 per 100 000 person-years, respectively.</p><p><b>CONCLUSION</b>Cigarette smoking is an important predictor for risk of all-causes of death as well as for cancer deaths. The change of smoking habit during the follow-up period could result in underestimating the deleterious effect of cigarette smoking on health.</p>