液体总摄人量和小便次数与上海市区居民膀胱癌危险性的关系

目的 探讨液体总摄入量和小便次数与上海市区居民膀胱癌危险性的关系.方法 采用全人群病例对照研究,共调查1996年1月1日至1998年12月31日期间诊断的上海市区膀胱癌新发病例608例,以及性别、年龄配对的人群对照607名.采用非条件logistic回归模型,调整可能的混杂因素,估计液体总摄人量和小便次数与膀胱癌发生的OR值及95%CI(α=0.05).结果 每天液体总摄人量及夜晚(即睡眠时间内)小便次数与膀胱癌发生的危险性无统计学意义的相关.白昼(即非睡眠时间内)通常小便次数与膀胱癌危险性呈负相关.调整年龄、性别、是否吸烟、液体总摄入量及其他因素后,与白昼通常小便次数≤3次者相比,小便次数为4、5及≥6次者的OR值分别为0.72(95%CI:0.49～1.05)、0.60(95%CI:0.41～0.87)和0.62(95%CI:0.43～0.90),趋势检验有统计学意义(P=0.014).与白昼通常小便次数≤3次者相比,白昼通常小便次数≥6次的吸烟者和不吸烟者的OR值分别为0.72(95%CI:0.45～1.15)和0.46(95%CI:0.25～0.87).与每天液体总摄入量≤750ml且白昼通常小便次数≤3次者相比,每天液体总摄人量＞1500ml且白昼通常小便次数≥6次者膀胱癌的危险性降低了57%,有统计学意义的相关性.结论 不憋尿且多饮水,尤其不吸烟者可以降低膀胱癌发生的危险性.

Total fluid intake, urination frequency and risk of bladder cancer: a population-based case-control study in urban Shanghai

Objective To evaluate the association between total fluid intake and the time of urination per day and the risk of bladder cancer. Methods A population-based case-control study was conducted in urban Shanghai, China, during January 1996 to December 1998. The study included 608 incident cases of bladder cancer and 607 age- and sex-matched controls. Unconditional logistic regression models were used to estimate the odds ratios(ORs)and their corresponding 95%confidence intervals(95%CIs)for bladder cancer associated with frequency of urination, after adjusted for age, gender, smoking status, history of occupation with high risk, history of bladder infections, body mass index and other confounding factors. The level of statistical significance was set at 0.05(two-sided). Results No significant trend was observed for the association between total fluid intake, time of nighttime urination and the risk of bladder cancer. Increasing time of urination during daytime was associated with decreased risk of bladder cancer(P for trend=0.014). ORs(95%CIs)for subjects who voided 4 times, 5 times and 6 or more times per day[0.72(0.49-1.05),0.60(0.41-0.87)and 0.62(0.43-0.90), respectively], when compared with those with less than 4times per day after adjustment of confounding factors. Data showed that smokers and nonsmokers who voided at least 6 times per day had the ORs of 0.72(95%CI: 0.45-1.15)and 0.46(95%CI:0.25-0.87)when compared to their counterparts who voided 3 times or less per day during the daytime. Subjects who urinated at least 6 times per day and consumed more than 1500 ml of total fluid per day experienced a significant 57% reduction in risk compared to subjects who urinated 3 times or less and consumed less than 750 ml of total daily fluid intake. Conclusion Increased urination frequency and total fluid intake, especially among those who never smoked might be associated with a reduced risk of bladder cancer.