Adults exposed as children to their parents’ cigarette smoking are much more likely than offspring of non-smokers to go on to suffer atrial fibrillation (AF), even allowing for their own smoking status, according to a new analysis.* The authors of the study said in the Journal of the American College of Cardiology that the new association that they found “offers new evidence to motivate smoking avoidance and cessation” – and that in order to reduce the global burden of AF it is imperative to address modifiable risk factors such as cigarette smoking.
The researchers pointed out that not only is cigarette smoking well known to increase the risk of AF, but recent cross-sectional studies have suggested a link between parental smoking and AF risk; so they analysed data for participants in the Framingham Heart Study, with known parental smoking status during the offspring’s childhood (up to the age of 18), to assess whether or not parental smoking predicted offspring AF.
They found that 82% of the 2,816 participants with information available (just over half of the total), were exposed to parental smoking. Over a mean follow up of 40.5 years, 14.3% of the 2,816 developed AF – assessed from medical records, ECGs and Holter monitors.
The study authors calculated that for every pack/day increase in parental smoking, there was an 18% increase in AF incidence in offspring. They also reported that parental smoking was a risk factor for offspring smoking (adjusted odds ratio, OR 1.34). However, offspring smoking mediated only 17% of the relationship between parental smoking and AF incidence.
They concluded: “Childhood secondhand smoke exposure predicted increased risk for adulthood AF after adjustment for AF risk factors. Some of this relationship may be mediated by a greater propensity among offspring of smoking parents to smoke themselves. These findings highlight potential new pathways for AF risk that begin during childhood, offering new evidence to motivate smoking avoidance and cessation.”
And they added: “With the rising prevalence of AF, it is imperative to address modifiable risk factors such as cigarette smoking to reduce the global burden of AF.”
A commentator on the study said it had certain limitations, such as lack of data on parental smoking for nearly half of participants, and that participants were mainly white and from one geographical area; but she agreed** that this ‘unique’ and methodologically strong study indicated that secondhand smoke exposure in childhood is a risk factor for future AF.
* Groh CA, Vittinghoff E, Benjamin EJ, et al. Childhood tobacco smoke exposure and risk of atrial fibrillation in adulthood. J Am Coll Cardiol. 2019 Oct, 74 (13) 1658-1664. Published online September 23, 2019.
** Chamberlain AM. Secondhand smoke and atrial fibrillation. J Am Coll Cardiol. 2019 Oct, 74 (13) 1665-1666. Published online September 23, 2019.