Associations of sleep quality and exercise frequency and the risk of coronary heart disease in Chinese urban elderly: a secondary analysis of cross-sectional data

Abstract

Background: Sleep quality and exercise frequency are closely associated with coronary heart disease (CHD). Few studies focused on the joint effect of initiating sleep, sleep disorders, and exercise frequency on the risk of CHD in the elderly. We used a secondary data analysis based on Boshan Elderly cross-sectional study. We explored the sleep quality, exercise frequency, and their joint effects on the risk of CHD.

Methods: We collected 678 participants whose age ≥ 60 years old from Boshan District Hospital. We used the Pittsburgh Sleep Quality Index to evaluate the sleep quality and obtained physical examination information from the hospital.

Results: Compared with the non-CHD group, patients with CHD spent more time in initiating sleep (time ≥ 60 min, 34.59% vs. 22.93%, P = 0.025) and less time exercising (exercise frequency < 1 times/week, 23.90% vs. 17.15%, P = 0.024). In multiple logistic regression analysis, sleep latency ≥ 60 min was associated with CHD risk (adjusted OR = 1.83; 95% CI: 1.11, 2.99; P-trend = 0.008). The adjusted OR (95% CI) of CHD was 2.24 (1.16, 4.34) for sleep duration < 5 h versus 5-9 h. Compared with exercise frequency < 1 times/week, the adjusted OR for exercise frequency ≥ 1 times/week was 0.46 (95% CI: 0.26, 0.83; P = 0.010). In addition, the joint effects of long sleep latency (≥ 60 min) and sleep disorders were associated with CHD (adjusted OR = 3.36; 95% CI: 1.41, 8.02). The joint effect of exercise frequency ≥ 1 times/week and sleep onset latency within normal limits (< 30 min) was also associated with CHD, and the adjusted OR (95% CI) was 0.42 (0.21, 0.87).

Conclusions: Long sleep latency, high frequency of initiating sleep difficulty, sleep disorders, and short sleep duration were positively associated with CHD. In addition, the joint effects of long sleep latency and sleep disorders were positively correlated with CHD incidence. However, the joint effects of exercise frequency ≥ 1 times/week and normal sleep onset latency were negatively associated CHD.

Keywords: Coronary heart disease; Elderly; Exercise frequency; Initiating sleep; Sleep disorder; Sleep duration.

Fig. 1

Multivariate logistic regression of lifestyle, disease history and sleep quality and the risk of CHD. Model c: adjusted factors were age, sex, BMI, hyperlipidemia, diabetes and hypertension. Model d: adjusted factors were age, sex, BMI, exercise frequency, hyperlipidemia, diabetes and hypertension. Each group adjusted by the other covariates except itself

Fig. 2

Multivariate regression analysis of initiating sleep and the risk of CHD subgrouping by sex. Model a: adjusted factors were age, BMI, hyperlipidemia, diabetes and hypertension. Model b: adjusted factors were age, BMI, exercise frequency, hyperlipidemia, diabetes and hypertension

Fig. 3

Joint effects of sleep latency and sleep disorders, and exercise frequency and sleep onset latency on the risk of CHD. A: The joint effect of (A) sleep onset latency (minutes) and sleep disorders and the risk of CHD. Short sleep latency (< 15 min) and non-sleep disorders was reference group. Model A was adjusted by age, sex, BMI, exercise frequency, hyperlipidemia, diabetes and hypertension. B: The joint effect of exercise frequency (< 1 times/week, ≥ 1 times/week and Every day) and initiating sleep and the risk of CHD. Good initiating sleep and exercise frequency < 1 times/week was reference group. Model B was adjusted by age, sex, BMI, hyperlipidemia, diabetes and hypertension (*P < 0.05)