Secondhand smoke during pregnancy and early childhood linked to atrial fibrillation in adult life

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A first-of-its-kind study indicates that gestational and early life secondhand smoke exposure may double one’s chance of developing atrial fibrillation as an adult.

The study by UC San Francisco researchers was published online in HeartRhythm. The study is being published in tandem with Atrial Fibrillation Awareness Month this September to help further inform the public about atrial fibrillation and potential risk factors.


Of the 4,976 participants of the study, 593 (11.9%) reported having atrial fibrillation. In unadjusted analyses, participants with atrial fibrillation were more likely to have been exposed to secondhand smoke exposure in utero, as a child, as an adult, at home and at work.


After adjusting for potential confounding factors, having had a smoking parent during gestational development (p=0.009) and residing with a smoker during childhood (p=0.007) were each significantly associated with atrial fibrillation. Furthermore, both positive associations were more pronounced among patients without risk factors for atrial fibrillation such as older age, hypertension, coronary heart disease and congestive heart failure.


The study includes data from the Health eHeart Study, which is an internet-based, longitudinal, cardiovascular cohort study.

The study participants completed baseline secondhand smoke exposure and medical conditions questionnaires. Secondhand smoke exposure was assessed through a validated 22-question survey, and prevalent atrial fibrillation was assessed by a self-report, with validation by review of electronic medical records. Analysis was performed to determine whether the presence or absence of at least one risk factor for atrial fibrillation modified the relationship between secondhand smoke and atrial fibrillation.


“Since there are no primary prevention strategies for atrial fibrillation, our discovery of a modifiable risk factor like secondhand smoke is very important,” says Gregory Marcus, associate professor at the UCSF School of Medicine and senior author of the study. “A first step to preventing atrial fibrillation is to become aware of risk factors that affect your heart and might at least theoretically be avoided. Our study further underscores the significance of living a heart-healthy lifestyle and making smarter choices like abstaining from smoking and protecting families from secondhand smoke.”


The study authors note that future research into the effects of secondhand smoke is needed to reveal novel mechanisms underlying atrial fibrillation and consequently new therapeutic options. Furthermore, research is needed to detect additional causes of lone atrial fibrillation in order to identify prevention strategies.


The Health eHeart Study seeks to develop strategies to prevent and treat all aspects of heart disease, and encourage a healthy lifestyle, free of heart disease. The study uses technology such as smartphone apps, sensors and other devices to gather data and aims to enrol up to one million participants. Anyone 18 years of age or older with internet access is encouraged to join.

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