Sleep timing and the prevalence of hypertension in middle-aged and older populations: the sleep heart health study.

OBJECTIVES

Sleep characteristics such as duration, continuity, and irregularity are associated with the risk of hypertension. This study aimed to investigate the association between sleep timing (including bedtime, wake-up time, and sleep midpoint) and the prevalence of hypertension.

METHODS

Participants were selected from the Sleep Heart Health Study (n = 5504). Bedtime and wake-up times were assessed using sleep habit questionnaires. The sleep midpoint was calculated as the halfway point between the bedtime and wake-up time. Restricted cubic splines and logistic regression analyses were performed to explore the association between sleep timing and hypertension.

RESULTS

A significant nonlinear association was observed between bedtime (P<0.001; P<0.001), wake-up time (P=0.024; P=0.076), sleep midpoint (P=0.002; P=0.005), and the prevalence of hypertension after adjusting for potential confounders. Multivariable logistic regression showed that both late (> 12:00 and 23:01 to 12:00) and early (≤ 22:00) bedtimes were associated with an increased risk of hypertension compared to bedtimes between 22:01 and 23:00. In addition, individuals with late (> 7:00) and early (≤ 5:00) wake-up times had a higher prevalence of hypertension than those with wake-up times ranging between 5:01 and 6:00. Delaying the sleep midpoint (> 3:00) was also associated with an increased risk of hypertension. Furthermore, no significant interaction effect was found in the subgroup analyses stratified by age, sex, or apnea-hypopnea index.

CONCLUSIONS

Our findings identified a nonlinear association between sleep timing and hypertension. Individuals with both early and late sleep timing had a high prevalence of hypertension.