UC Davis

Background: Several studies have found significant associations between habitual sleep duration and hypertension risk in the general population. However, there is limited literature on predictors of sleep duration in populations with hypertension or how sleep duration correlates with hypertension control. This research dissertation, focused on United States (US) adults with hypertension, aims to: 1) identify factors associated with habitual sleep duration among adults with hypertension; 2) examine the relationship between habitual sleep duration and hypertension control, and 3) determine if the relationship between habitual sleep duration and hypertension control is modified by age or gender. Methods: The 2015-2018 National Health and Nutrition Examination Survey data for US adults who met the hypertension criteria (systolic blood pressure (BP) ≥130 mmHg or diastolic BP ≥80 mmHg, or current intake of BP-lowering medications) was used for the study. Survey weighted multinomial logistic regression models were fit to examine factors associated with short (<7 hours) and long (>9 hours) sleep duration with adequate sleep duration (7 – 9 hours) as the reference. Survey-weighted multivariable logistic regression models were fit to examine the association between habitual sleep duration (<6, 6 - <7, 7 - 9 (reference), and >9 hours) and hypertension control (BP <130/80mmHg versus ≥130/80mmHg). Additional analyses tested effect modification of the relationships between habitual sleep duration and hypertension control by age or gender.

Results: The prevalence of self-reported adequate sleep duration was 65.7%, while short sleep duration was 23.6%, and long sleep duration, 10.7%. Short sleep duration (compared to adequate sleep duration) was positively associated with history of seeking help for sleeping difficulties (relative risk ratio [RRR], 1.25; 95% confidence interval [CI], 1.02 – 1.53), Non-Hispanic Black race/ethnicity (RRR, 2.08; 95% CI, 1.61 – 2.67), working ≥45 hours/week (RRR, 1.81; 95% CI, 1.32 – 2.48), and negatively associated with older age ≥ 65 years (RRR, 0.63; 95% CI, 0.45 – 0.91) and female gender (RRR, 0.70; 95% CI, 0.56 – 0.88). Long sleep duration was positively associated with female gender (RRR, 1.24; 95% CI, 1.001 – 1.54), chronic kidney disease (RRR, 1.48; 95% CI, 1.14-1.92), moderate depressive symptoms (RRR, 1.62; 95% CI, 1.08 – 2.44), moderately severe to severe depressive symptoms (RRR, 1.89; 95% CI, 1.05 – 3.43), being in retirement (RRR, 3.46; 95% CI, 2.18 – 5.49), and not working due to health reasons (RRR, 4.87; 95% CI, 2.89 – 8.22) or other reasons (RRR, 3.29; 95% CI, 1.84 – 5.88). In the fully adjusted model, habitual sleep duration of <6 hours/main sleep period was associated with reduced odds of hypertension control (OR = 0.66, 95% CI: 0.46 – 0.95, P = 0.027) when compared to 7 – 9 hours. No significant differences were noted in hypertension control between the reference group (7 - 9 hours) and the 6 - <7 or >9 hours groups. There were no significant differences across age groups or gender in the relationship between habitual sleep duration and hypertension control.

Conclusion: In adults with hypertension, factors independently associated with habitual sleep duration include help-seeking for sleeping difficulty, gender, age, chronic kidney disease, depressive symptoms, race/ethnicity, and employment status. The results show that a habitual sleep duration of <6 hours is associated with reduced odds for hypertension control, which indicates that promoting adequate habitual sleep duration may help improve hypertension control, especially in those who habitually sleep less than 6 hours a day. These findings can help in the development of tailored approaches for promoting adequate sleep duration in adults with hypertension.