Sleep-Wake Concordance in Couples Is Inversely Associated with Cardiovascular Disease Risk Markers

AIM: To determine whether interdependence in couples' sleep (sleep-wake concordance i.e., whether couples are awake or asleep at the same time throughout the night) is associated with two markers of cardiovascular disease (CVD) risk, ambulatory blood pressure (BP) and systemic inflammation. METHODS: This community-based study is a cross-sectional analysis of 46 adult couples, aged 1845 years, without known sleep disorders. Percent sleepwake concordance, the independent variable, was calculated for each individual using actigraphy. Ambulatory BP monitors measured BP across 48 h. Dependent variables included mean sleep systolic BP (SBP) and diastolic BP (DBP), mean wake SBP and DBP, sleepwake SBP and DBP ratios, and C-reactive protein (CRP). Mixed models were used and were adjusted for age, sex, education, race, and body mass index. RESULTS: Higher sleepwake concordance was associated with lower sleep SBP (b . -.35, SE . .01) and DBP (b . -.22, SE . .10) and lower wake SBP (b . -.26, SE . .12; all p values < .05). Results were moderated by sex; for women, high concordance was associated with lower BP. Men and women with higher sleepwake concordance also had lower CRP values (b . -.15, SE . .03, p < .05). Sleepwake concordance was not associated with wake DBP or sleep/wake BP ratios. Significant findings remained after controlling for individual sleep quality, duration, and wake after sleep onset. CONCLUSIONS: Sleepwake concordance was associated with sleep BP, and this association was stronger for women. Higher sleepwake concordance was associated with lower systemic inflammation for men and women. Sleepwake concordance may be a novel mechanism by which marital relationships are associated with long-term CVD outcomes.