Background: Self-assessed short sleep duration have previously been reported to be associated with increased risk of cardiovascular disease. However, other studies do not support this finding.
Purpose: To investigate whether short sleep duration at fifty years of age is associated with increased risk of major adverse cardiovascular events (MACE) during a 21-year follow-up period.
Methods: In 1993 50% (n=1463) of all men living in Gothenburg, born in 1943, were invited to participate. Of those 798 (54%) accepted and filled out questionnaires (including questions about average duration of sleep per day), underwent physical examination, ECG and blood pressure monitoring and anthropometric data were measured. Re-examinations were conducted in 2003 and in 2014. MACE was assessed by a combination of review of medical records of all participants, the Swedish Hospital Discharge registry and the Swedish Death Cause registry. MACE were defined as: acute coronary syndrome, stroke, TIA or heart failure.
Results: Nineteen subjects were excluded because of inadequate sleep questionnaires, and 19 were excluded since they had MACE before baseline. Thus, 760 individuals were included in the final analysis, in total 14,848 person-years at risk. Men with short sleep time had more hypertension and more diabetes, were more obese, were to a larger extent smokers/former smokers, were less physically active and had worse sleep quality. Kaplan-Meier analyses showed an increased risk of MACE in those with sleep less than five hours per night compared to the group set as reference (7–8 hours), p=0.003. Patients with a sleep time of <5 hours had an almost two time higher risk of developing MACE during the follow-up period. The risk increase remained almost the same after adjustment for confounders (Table 2). If, in addition to those with MACE, all those with hypertension at baseline also were excluded, the hazard ratio (HR) for developing MACE remained significant with HR 2.45 (95% confidence interval [CI]1.34 - 4.46) in univariate and HR; 2.39 (95% CI 1.31 - 4.35) in multivariate analysis.
Conclusion: Sleep duration of five hours or less per night in those middle-aged men was associated with a two-fold higher risk of developing cardiovascular disease 2 decades beyond.