Centre for Population Health Sciences, University of Glasgow, Glasgow G12 8RZ, UK.
J Public Health (Oxf). 2011 Dec;33(4):496-502. doi: 10.1093/pubmed/fdr025. Epub 2011 Mar 21.
Active smoking is a recognized risk factor for stroke. We determined the evidence for an association with secondhand smoke exposure.
A systematic review was undertaken according to PRISMA guidelines. Random effects meta-analysis provided a pooled estimate of risk, and heterogeneity quantified using I(2) values. Potential publication and study bias were assessed using a funnel plot and Egger's test. Meta-regression analyses were used to investigate sources of heterogeneity.
The 20 eligible studies provided 35 estimates of risk derived from 885 307 participants, of whom 5894 (0.7%) suffered a stroke. The pooled estimate of risk was 1.25 (95% CI: 1.12-1.38) with no evidence of significant publication or small-study bias. There was moderate heterogeneity (I(2) = 54.2%, P < 0.001) but no study characteristics were statistically significant in the meta-regression analysis. There was a non-linear dose relationship. The relative risk increased from 1.16 (95% CI: 1.06-1.27) for exposure to 5 cigarettes/day to 1.56 (95% CI: 1.25-1.96) for exposure to 40 cigarettes/day.
There is evidence of a strong, consistent and dose-dependent association between exposure to secondhand smoke and risk of stroke, suggestive of a causal relationship, with disproportionately high risk at low levels of exposure suggesting no safe lower limit of exposure.
主动吸烟是公认的中风危险因素。我们确定了与二手烟暴露相关的证据。
根据 PRISMA 指南进行系统评价。随机效应荟萃分析提供了风险的汇总估计值，并使用 I(2)值量化异质性。使用漏斗图和 Egger 检验评估潜在的发表偏倚和研究偏倚。Meta 回归分析用于研究异质性的来源。
20 项符合条件的研究提供了 35 项来自 885307 名参与者的风险估计值，其中 5894 名（0.7%）发生了中风。风险的汇总估计值为 1.25（95%CI：1.12-1.38），没有证据表明存在显著的发表偏倚或小样本偏倚。存在中度异质性（I(2) = 54.2%，P < 0.001），但元回归分析中没有研究特征具有统计学意义。存在非线性剂量关系。相对风险从每天接触 5 支香烟的 1.16（95%CI：1.06-1.27）增加到每天接触 40 支香烟的 1.56（95%CI：1.25-1.96）。
有证据表明，二手烟暴露与中风风险之间存在强烈、一致且剂量依赖性的关联，提示存在因果关系，而且在低暴露水平下风险过高，表明不存在安全的低暴露下限。
