Chronotype reflects time of day preferences for performing daily activities. Previous research within Asian and European cohorts indicates evening chronotype is associated with elevated cardiometabolic risk. However, evidence is limited from population-based US cohorts, particularly among women in whom evening chronotype prevalence may become higher after middle-age, coinciding with life stages associated with higher cardiovascular disease (CVD) risk. This cross-sectional study evaluated associations of chronotype with overall cardiovascular health (CVH), health behaviors, and cardiometabolic risk factors among 506 women (mean age = 37 ± 16y, 62% racial/ethnic minority) in the American Heart Association (AHA)'s Go Red for Women Strategically-Focused Research Network cohort at Columbia University (New York City, NY, USA). Chronotype was assessed using the validated Morningness-Eveningness Questionnaire (MEQ) and categorized as "evening", "intermediate", and "morning" chronotypes. Health behaviors (diet, physical activity, and sleep) were assessed using validated questionnaires. Anthropometrics, clinical blood pressure, and blood biomarkers were assessed at the clinic visit. CVH was evaluated using the AHA Life's Simple 7 (LS7) metrics; LS7 scores of 0-8 and 9-14 were considered indicative of poor and moderate-to-high CVH, respectively. Linear and logistic regression models adjusted for age, race/ethnicity, education, health insurance, and menopausal status were used to examine associations of MEQ scores and chronotype categories with overall CVH, clinical cardiometabolic risk factors, and health behaviors. Overall, 13% of women identified as evening chronotypes, while 55% and 32% reported being intermediate and morning types. In linear models, higher MEQ scores were associated with higher AHA LS7 scores (β(SE) = 0.02(0.01); p = .014), indicative of more favorable CVH, and with health behaviors not included in the LS7. Higher MEQ scores were also associated with lower Pittsburgh Sleep Quality Index, i.e. better sleep quality, (β(SE) = -0.07(0.02), p < .0001), lower insomnia severity (β(SE) = -0.14(0.01), p < .0001), shorter time to fall asleep (β(SE) = -0.28(0.14), p = .044), and less sedentary time (β(SE) = -0.11(0.03), p = .001). In logistic regression models, evening chronotype, compared to intermediate/morning type, was associated with higher odds of having poor CVH (OR(95%CI):2.41(1.20-4.85)), not meeting AHA diet (OR(95%CI):2.89(1.59-5.23)) and physical activity guidelines (OR(95%CI):1.78(1.03-3.07)), and having short sleep (OR(95%CI):2.15(1.24-3.73)) or insomnia (OR(95%CI):2.69(1.53-4.75)). The evening type compared to morning type was also associated with being a current smoker (OR(95%CI):2.14(1.02-4.52)) and having poor sleep quality (OR(95%CI:2.35(1.27-4.37)) and long sleep onset latency (OR(95%CI:1.89(1.00-3.56)). In our cohort of women, evening chronotype was related to poor CVH, likely driven by its influence on health behaviors. These findings, although warranting confirmation prospectively in other populations, suggest chronotype is an important factor to consider and possibly target when designing lifestyle interventions for CVD prevention.
Keywords: Chronotype; cardiovascular health; heath behaviors; sleep; women.