In their interesting article, Dublin et al1 explore in a population-based case-control study both the risk of new-onset atrial fibrillation (AF) according to body mass index and the extent to which the association between obesity and AF risk may be mediated by traditional cardiovascular risk factors.
Our comments are focused on the likely role of obstructive sleep apnea (OSA) as one other possible factor contributing to the described association between obesity and new-onset AF, an aspect not evaluated in this study. Obstructive sleep apnea affects 17% to 24% of North Americans adults,2 and patients with AF have a high prevalence of OSA.3 This medical condition is characterized by periodic reduction or cessation of breathing due to narrowing of the upper airways during sleep. Obstructive sleep apnea induces intermittent hypoxia, hypercapnia, sympathetic activation, and abrupt surges in arterial pressure, and it is conceivable that these factors would predispose to the development of AF. Among patients with OSA who underwent electrical cardioversion for AF, in those correctly treated with continuous positive airway pressure (the preferred treatment for OSA), a reduction in the recurrence rate for AF throughout the 1-year follow-up was reported by nearly 50%, compared with those with untreated OSA.4