UCSF

Background

Cigarette smoking is a risk factor for atrial fibrillation (AF), but whether secondhand smoke (SHS) impacts the risk of AF remains unknown.

Objective

To determine if SHS exposure is associated with an increased risk of AF.

Methods

We performed a cross-sectional analysis of data from participants enrolled in the Health eHeart Study, an internet-based, longitudinal cardiovascular cohort study, who completed baseline SHS exposure and medical conditions questionnaires. SHS was assessed through a validated 22-question survey, and prevalent AF was assessed by self-report, with validation of a subset (n = 42) by review of electronic medical records.

Results

Of 4976 participants, 593 (11.9%) reported having AF. In unadjusted analyses, patients with AF were more likely to have been exposed to SHS in utero, as a child, as an adult, at home, and at work. After multivariable adjustment for potential confounders, having had a smoking parent during gestational development (OR 1.37, 95% CI 1.08-1.73, P = .009) and residing with a smoker during childhood (OR 1.40, 95% CI 1.10-1.79, P = .007) were each significantly associated with AF. Both positive associations were more pronounced among patients without risk factors for AF (P values for interaction <.05).

Conclusions

SHS exposure during gestational development and during childhood was associated with having AF later in life. This association was even stronger in the absence of established risk factors for AF. Our findings indicate that SHS in early life may be an important, potentially modifiable risk factor for the development of AF.