Sleep quality and risk of coronary heart disease - a prospective cohort study from the English longitudinal study of ageing

Background: The association between sleep quality and risk of coronary heart disease (CHD) remains unclear in the elderly. Results: At eight-year follow up, a total of 411 (4.29%) participants developed CHD. Compared with good quality group, the multivariable hazard ratio [HR] (95% confidence interval [CI]) for CHD was 1.393 (1.005, 1.931) for intermediate quality group and 1.913 (1.206, 3.035) for poor quality group. Consistent results were observed in participants with normal sleep duration. Conclusions: Poor sleep quality may be a novel modifiable risk factor for CHD in the elderly independent of conventional cardiovascular risk factors, even when sleep duration was normal. Methods: The current study included 9570 CHD-free participants in the English Longitudinal Study of Ageing (ELSA) from wave 4 (2008 to 2009). Incident CHD included new onset angina or myocardial infarction. Sleep quality was measured by a four-item questionnaire. Score ranged from 1 (best) to 4 (poorest). Participants were divided into three groups: good quality (1 ≤ score <2), intermediate quality (2 ≤ score <3) and poor quality (3 ≤ score ≤4). Cox regression model was used to calculate HR for CHD risk according to sleep quality, adjusted for conventional CHD risk factors and sleep duration.