Abstract WP226: Secondhand Smoking And Odds Of Stroke Among Non-smoking Indigenous Africans From Ghana And Nigeria: A Matched Case-control Study

Abstract

Introduction: Second-hand smoking (SHS) is an emerging phenomenon in cardiovascular disease (CVD) epidemiology, but whether SHS is associated with stroke is not clearly understood. We assessed the association between SHS and stroke risk in a cohort of West Africans in the Stroke Investigative Research and Educational Network (SIREN) study. Hypothesis: SHS is not associated with stroke among indigenous West Africans from Ghana and Nigeria. Methods: 3131 stroke cases who had never smoked matched (for age and sex) with 3131 healthy smoke-free controls were identified in the multi-centre SIREN study in Ghana and Nigeria. Information on SHS was obtained through the collection of data on regular exposure to exhaled smoke or burning tobacco in an indoor environment. We assessed the relationship between SHS and stroke by estimating the odds ratio (OR) and 95% confidence interval (CI) using conditional logistic regression, adjusting for relevant covariates at P <0.05 in a two-sided test. Results: The mean age of the participants was 58.8±14.1years (males, 48.0%). History of exposure to SHS was present in 20.2% of the overall sample. The multivariable-adjusted OR for the association between SHS and all stroke events was 1.12 (0.93, 1.34), P = 0.210. When the association was stratified by stroke type, the multivariable-adjusted OR were 1.42 (1.03, 1.98) P = 0.033 for haemorrhagic stroke and 1.01 (0.80, 1.26) P = 0.935 for ischaemic stroke. Conclusion(s): SHS was independently associated with higher odds of haemorrhagic stroke, but not ischaemic stroke in this cohort of indigenous West Africans. Intervention(s) to reduce SHS might help lower the burden of stroke in this population, pending longitudinal studies to evaluate the causal effect of SHS on stroke.