Sleep duration irregularity spells increased risk of major CVD events

Higher night‐to‐night variation in sleep duration may predispose individuals to major cardiovascular disease (CVD) events, regardless of the genetic CVD risk, according to a study.

The study included 86,219 UK Biobank participants who were free of CVD during completion of the 7-day accelerometer-based sleep assessment. Researchers examined sleep irregularity in relation to the incidence of major CVD events, defined as fatal or nonfatal myocardial infarction and stroke.

The mean irregularity in sleep duration was 56 min, with 29.5 percent of the participants having a night-to-night sleep duration variation of more than 60 min. Participants with higher sleep duration irregularity were less likely to be White and more likely to be younger, female, socioeconomically disadvantaged, employed in occupations requiring shift work, have higher BMI, and currently smoke.

A total of 2,310 cases of major CVD events, including 1,183 myocardial infarction and 1,175 stroke, occurred over 636,258 person‐years of follow‐up. In multivariable analysis, each 1‐h increase in sleep duration was associated with a 19-percent increased CVD risk (adjusted hazard ratio [aHR], 1.19, 95 percent confidence interval [CI], 1.10–1.27; p<0.0001), 23-percent increased myocardial infarction risk (aHR, 1.23, 95 percent CI, 1.11–1.35; p<0.0001), and 17-percent increased stroke risk (aHR, 1.17, 95 percent CI, 1.05–1.29; p=0.003). These point estimates were modestly attenuated following additional adjustment for lifestyle factors, comorbidities, and sleep‐related factors.

Of note, higher sleep irregularity was associated with higher CVD risk irrespective of genetic risk (p=0.43), although this association was more pronounced among participants with longer average sleep duration (>8 hours; p=0.006).