Environmental Tobacco Smoke Exposure and Risk of Stroke in Never Smokers: An Updated Review with Meta-Analysis

Objectives The study aimed to review the epidemiological evidence relating environmental tobacco smoke exposure to stroke in never smokers. Methods The study is similar to our review in 2006, with searches extended to March 2016. Results Twelve further studies were identified. A total of 28 studies varied considerably in design, exposure indices used, and disease definition. Based on 39 sex-specific estimates and the exposure index current spousal exposure (or nearest equivalent), the meta-analysis gave an overall fixed-effect relative risk estimate of 1.23 (95% confidence interval: 1.16-1.31), with significant ( P Conclusions Although other reviewers inferred a causal relationship, we consider the evidence does not conclusively demonstrate this. We repeat our call for publication of data from existing large prospective studies.