Second-Hand Tobacco Smoke in Never Smokers Is a Significant Risk Factor for Coronary Artery Calcification
Is there an association between second-hand tobacco smoke and coronary artery calcium (CAC)?
Data from the FAMRI-IELCAP (Flight Attendant Medical Research Institute International Early Lung Cancer Action Program) screening program were used for the present study. Never smokers, ages 40-80 years, who had completed a questionnaire on second-hand tobacco smoke and who had completed a low-dose nongated computed tomography scan were included. The questionnaire provided a quantitative score for total second-hand tobacco smoke, as well as separately as a child and as an adult at home and at work; four categories of exposure to second-hand tobacco smoke were identified (minimal, low, moderate, and high exposure). CAC was graded using a previously validated ordinal scale score that ranged from 0 to 12.
A total of 3,098 adults were included in this cohort. Participants with more than minimal second-hand tobacco smoke exposure were older, more frequently women, and more frequently had diabetes, hypercholesterolemia, and hypertension than those with minimal second-hand tobacco smoke exposure. The prevalence of CAC was 24% (n = 754) and was significantly higher in those with more than minimal second-hand tobacco smoke exposure compared with those with minimal second-hand tobacco smoke exposure (26% vs. 19%, p < 0.0001). The adjusted odds ratios for CAC prevalence were 1.54 (95% confidence interval [CI], 1.17-2.20) for low second-hand tobacco smoke exposure, 1.60 (95% CI, 1.21-2.10) for moderate exposure, and 1.93 (95% CI, 1.49-2.51) for high exposure. The association of the extent of second-hand tobacco smoke with the extent of CAC was confirmed by the adjusted odds ratio (p < 0.0001).
The investigators concluded that second-hand tobacco smoke was associated with CAC, in a dose-dependent fashion, suggesting that second-hand tobacco smoke exposure causes CAC.
These data suggest that efforts to reduce cardiovascular risk should include education on avoiding smoking, but also avoiding exposure to second-hand smoke. Furthermore, these data support policies which limit smoking in public areas.
Keywords: Coronary Artery Disease, Tobacco Smoke Pollution, Smoke, Cardiovascular Diseases, Confidence Intervals, Hypercholesterolemia, Hypertension, Diabetes Mellitus, Lung Neoplasms, Smoking
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