Sleep and risk for high blood pressure and hypertension in midlife women: the SWAN (Study of Women’s Health Across the Nation) Sleep Study

• We tested associations of polysomnography (PSG)-measured sleep and hypertension in midlife women.
• Lower nonrapid eye movement (NREM) total delta power predicts incident hypertension across 7 years.
• Quantitative electroencephalogram (EEG) measures may reveal new sleep parameters leading to hypertension.

ObjectiveInadequate self-reported sleep is related to high blood pressure (BP). Our study investigated cross-sectional and longitudinal relationships between poor sleep measured by in-home polysomnography (PSG) and BP.MethodsMidlife participants (132 black, 164 white, and 59 Chinese) were from the SWAN (Study of Women’s Health Across the Nation) ancillary sleep study. In-home PSG measured sleep apnea, duration, efficiency, and electroencephalogram (EEG) total delta and beta power during nonrapid eye movement (NREM) sleep. Women subsequently were followed annually for 4.5 (1–7) years for BP and hypertensive status (>140/90 mmHg or use of antihypertensive medication). Covariates were age, race, site, and educational attainment, with time-covariates of BP medications, body mass index, diabetes mellitus (DM), cigarette smoking, and menopausal status.ResultsSleep duration and efficiency were unrelated to BP cross-sectionally or longitudinally in multivariate models. Women with higher total beta power were more likely to be hypertensive at the time of the sleep study; women with lower total delta power were more likely to show increases in diastolic BP (DBP) and to be at risk for incident hypertension across follow-up.ConclusionsLow NREM delta power may be a risk factor for future hypertension. Quantitative EEG measures are worthy of future investigations of hypertension risk.