Abstract 29: Change in Healthy Sleep Score and Incident Cardiovascular Disease: A Combined Analysis of Two Independent Community-Based Cohorts

Introduction: Evidence on the link between sleep habits and cardiovascular diseases (CVD) in the community predominantly relies on studies that have investigated only one sleep habit, measure at one timepoint. Therefore, this study examined the joint effect of five sleep habits at baseline and at follow-up with incident CVD events. Hypothesis: We assessed the hypothesis that change in sleep habits over time including improvement in sleep habits and maintenance of a high level of sleep habits are related to reduced CVD risk. Methods: We combined data from two large independent community-based cohorts, the Paris Prospective Study 3 (France) and the CoLaus/PsyCoLaus study (Switzerland), involving 11 347 participants in total, aged 53–64 and comprising 44.6% women, initially free from CVD at baseline (respectively 2008-2012 and 2003-2006). Information on participants’ sleep habits were collected twice (median time interval between the 2 time points=2.0; interquartile range [IQR]: 2.0-5.2) by validated questionnaires. A healthy sleep score (HSS) combining five sleep habits (early chronotype, sleep duration of 7-8 h/day, never/rarely insomnia, no sleep apnea, and no frequent excessive daytime sleepiness) was calculated at baseline and follow-up. Each sleep habit was scored 1 point if optimal, otherwise 0 point. The score ranged from 0 to 5, reflecting the number of optimal sleep habits. Associations of HSS at baseline and the change in the score over time with CVD events (coronary heart disease, CHD, or stroke) were examined using Cox proportional hazard models. Results: During a median follow-up of 8.9 years (IQR: 8.0-10.0), 499 first CVD events occurred (339 CHD and 175 stroke). In multivariate Cox analysis, the risk of CVD decreased by 18% per one-point increment in the HSS (hazard ratio, HR=0.82 [95% confidence interval, CI, 0.76-0.89]). At follow-up, 38% remained in stable high score (score≥3 at both time points, the median of the baseline HSS), 11% had a stable low HSS (score<3 at both time points), 22% increased their scores and 29% decreased their scores respectively. After a median follow-up of 8.1 years (IQR: 8.0-10.0) following the second measure of the HSS, a total of 308 first CVD events occurred (227 CHD and 86 stroke). After adjusting for the baseline HSS and covariates, the risk of CVD decreased by 13% (HR=0.87 [0.76-0.99]) per unit of change in HSS. In particular, compared to participants with a decreasing HSS, those with a high stable HSS had a 39% decrease in CVD risk (HR=0.61 [0.45-0.81]). If all participants in this study had achieved a HSS of four and five, 29% and 60% of new CVD could have been avoided, respectively. Conclusions: Higher HSS and increase in the HSS are associated with a lower risk of CHD and stroke in the community. This study supports the promotion of healthy sleep habits in the population and strong collaboration between sleep medicine and CVD medicine.