Recent epidemiological studies have shown varying associations between coffee consumption and bladder cancer (BC). This research aims to elucidate the association between coffee consumption and BC risk by bringing together worldwide cohort studies on this topic. Coffee consumption in relation to BC risk was examined by pooling individual data from 12 cohort studies, comprising of 2601 cases out of 501,604 participants. Pooled multivariate hazard ratios (HRs), with corresponding 95% confidence intervals (CIs), were obtained using multilevel Weibull regression models. Furthermore, dose–response relationships were examined using generalized least squares regression models. The association between coffee consumption and BC risk showed interaction with sex (P-interaction < 0.001) and smoking (P-interaction = 0.001). Therefore, analyses were stratified by sex and smoking. After adjustment for potential confounders, an increased BC risk was shown for high (> 500 ml/day, equivalent to > 4 cups/day) coffee consumption compared to never consumers among male smokers (current smokers: HR = 1.75, 95% CI 1.27–2.42, P-trend = 0.002; former smokers: HR = 1.44, 95% CI 1.12–1.85, P-trend = 0.001). In addition, dose–response analyses, in male smokers also showed an increased BC risk for coffee consumption of more than 500 ml/day (4 cups/day), with the risk of one cup (125 ml) increment as 1.07 (95% CI 1.06–1.08). This research suggests that positive associations between coffee consumption and BC among male smokers but not never smokers and females. The inconsistent results between sexes and the absence of an association in never smokers indicate that the associations found among male smokers is unlikely to be causal and is possibly caused by residual confounding of smoking.

最近的流行病学研究表明，咖啡摄入量与膀胱癌（BC）之间存在各种关联。这项研究旨在通过汇集有关该主题的全球队列研究来阐明咖啡消费与卑诗省风险之间的关联。通过汇总12项队列研究的个人数据，检查了与BC风险相关的咖啡消费量，其中包括501604名参与者中的2601例。使用多级Weibull回归模型获得具有相应95％置信区间（CI）的汇总多元风险比（HRs）。此外，使用广义最小二乘回归模型检查了剂量反应关系。咖啡消费与BC风险之间的相关性显示与性交（P-交互作用<0.001）和吸烟（P-互动= 0.001）。因此，分析按性别和吸烟进行了分层。调整了潜在的混杂因素后，与男性吸烟者（从业者：HR = 1.75，95％CI 1.27）从不喝咖啡相比，高咖啡摄入量（> 500 ml /天，相当于> 4杯/天）的BC风险增加。 –2.42，P-趋势= 0.002；曾吸烟者：HR = 1.44，95％CI 1.12–1.85，P-趋势= 0.001）。此外，男性吸烟者的剂量反应分析还显示，每天饮用咖啡的不列颠哥伦比亚省患病风险增加了500毫升/天（4杯/天）以上，每杯咖啡（125毫升）的患病风险增加了1.07（95％） CI 1.06-1.08）。这项研究表明，男性吸烟者中咖啡摄入量与BC之间呈正相关，但女性和吸烟者之间并非如此。性别之间的不一致结果和从不吸烟的人之间没有关联，这表明在男性吸烟者中发现的关联不太可能是因果关系，并且可能是由残留的吸烟混杂引起的。