Sleeping and the risk of atrial fibrillation: a prospective study in the SUN cohort

To assess the association between daytime napping, night sleeping time and the incidence of atrial fibrillation (AF) in a Mediterranean cohort.

We conducted a prospective cohort study of Spanish university graduates (The SUN Project), involving 20,827 participants, free of AF at baseline. Participants were followed-up for a median of 15 years (retention proportion: 91%). Daytime nap and night sleep duration were assessed at baseline, and incident AF cases were confirmed by a cardiologist following a prespecified protocol. Multivariable Cox regression models estimated hazard ratios (HR) for AF according to sleeping patterns. During follow-up, 163 incident cases of AF were identified. Compared to participants who took short naps (<30 min/day), those with long naps (≥30 min/day) had a 62% higher risk of AF (adjusted HR= 1.62; 95% CI: 1.10, 2.39). No significant association was observed for participants who did not sleep a nap (adjusted HR = 1.32; 95% CI: 0.91, 1.93) compared to a short nap. In the same model, inadequate night sleep duration (<6 h/day or >8 h/day) had a higher risk of AF (adjusted HR = 1.89; 95% CI: 1.10, 3.23) compared to sleeping 6-8 h/day. The highest AF risk was observed in participants with both long naps (≥30 min/day) and inadequate nighttime sleep (<6 h/day or >8 h/day), with a threefold increased risk (adjusted HR = 3.19; 95% CI: 1.30, 7.79).

Prolonged daytime naps and inadequate night sleep duration were significantly associated with a higher risk of AF in a Mediterranean cohort.