Childhood and adult exposure to secondhand tobacco smoke and cardiac structure and function: results from Echo-SOL.

Objective: To describe the relationship of household secondhand smoke (SHS) exposure and cardiac structure and function.

Methods: Participants (n=1069; 68 % female; age 45-74 years) without history of tobacco use, coronary artery disease or severe valvular disease were included. Past childhood (starting at age <13 years), adolescent/adult and current exposure to household SHS was assessed. Survey linear regression analyses were used to model the relationship of SHS exposure and echocardiographic measures of cardiac structure and function, adjusting for covariates (age, sex, study site, alcohol use, physical activity and education).

Results: SHS exposure in childhood only was associated with reduced E/A velocity ratio (β=-0.06 (SE 0.02), p=0.008). SHS exposure in adolescence/adult only was associated with increased left ventricular ejection fraction (LVEF) (1.2 (0.6), p=0.04), left atrial volume index (1.7 (0.8), p=0.04) and decreased isovolumic relaxation time (-0.003 (0.002), p=0.03). SHS exposure in childhood and adolescence/adult was associated with worse left ventricular global longitudinal strain (LVGLS) (two-chamber) (0.8 (0.4), p= 0.049). Compared with individuals who do not live with a tobacco smoker, individuals who currently live with at least one tobacco smoker had reduced LVEF (-1.4 (0.6), p=0.02), LVGLS (average) (0.9 (0.40), p=0.03), medial E' velocity (-0.5 (0.2), p=0.01), E/A ratio (-0.09 (0.03), p=0.003) and right ventricular fractional area change (-0.02 (0.01), p=0.01) with increased isovolumic relaxation time (0.006 (0.003), p=0.04).

Conclusions: Past and current household exposure to SHS was associated with abnormalities in cardiac systolic and diastolic function. Reducing household SHS exposure may be an opportunity for cardiac dysfunction prevention to reduce the risk of future clinical heart failure.