LAUSR

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Regional Development Fund (FEDER) and Spanish Ministry of Health. Previous research has identified a potential relationship between sleep patterns and atrial fibrillation (AF). Short daytime napping is a widespread healthy habit particularly in Mediterranean countries. However, as far as we know, daytime napping and the risk of developing AF has not been analysed before. Our objective was to assess the association between daytime napping and the incidence of AF in a Mediterranean cohort. The SUN project is a dynamic, prospective cohort of Spanish university graduates. A total of 20,348 participants, free of AF at baseline, were followed-up for a median time of 13.8 years, with a retention proportion of 91%. Daytime napping was assessed at baseline and participants were categorised according to their average daily napping time. Incident cases of AF were confirmed by a cardiologist according to a prespecified protocol. Multivariable Cox regression models were used to estimate hazard ratios (HR) of AF according to daytime napping time. During follow-up, we identified 131 incident cases of AF. In comparison to participants with short daytime napping (<30 minutes/day), those who slept ≥30 minutes/day exhibited a significant 90% higher relative risk of incident AF (adjusted HR= 1.90; 95% CI: 1.26, 2.86), whereas no significant risk was observed for participants who did not have nap (adjusted HR = 1.26; 95% CI: 0.82, 1.93). After excluding participants that reported not having nap, those with shorter daytime napping had a lower risk of developing AF, with the greatest risk reduction between 15-30 minutes/day (adjusted HR = 0.44; 95% CI: 0.27, 0.72), in comparison to sleeping >30 minutes/day. Daytime napping was significantly associated with the risk of developing AF. Sleeping a longer nap (≥30 minutes/day) was associated with an increased risk, while a shorter nap between 15-30 minutes/day was associated with a lower risk of incident AF. These findings suggest a potential novel healthy lifestyle habit in the primary prevention of AF.