Joint associations of device-measured physical activity and sleep duration with cardiometabolic health in the 1970 British Cohort Study

Objectives: Multiple unhealthy lifestyle behaviors could synergistically exaggerate unfavorable health outcomes. The present study aimed to investigate the joint associations of device-measured sleep duration and physical activity with cardiometabolic health markers. Design: A cross-sectional analysis embedded in the 46–48 years wave of the 1970 British Cohort Study. Methods: 4756 participants wore an activPAL3 micro accelerometer to measure physical activity and sleep duration. Outcomes included body mass index (BMI), glycated hemoglobin, triglycerides, c-reactive protein, systolic blood pressure, and total-to-high-density lipoprotein (HDL) cholesterol ratio, hypertension, and diabetes. We examined the joint associations of sleep (<7 h, short; 7–9 h, medium; >9 h, long) and physical activity (median cut of step counts, 4740 steps/d; or moderate-to-vigorous physical activity, MVPA, 085 h/d) with outcomes by generalized linear models or logistic regression. Results: Low physical activity combined with either short or long sleep was associated with higher BMI (e.g., 2.32 [1.42, 3.23] (kg/m²) for short sleep) compared to the referent medium sleep and high physical activity combination. Low physical activity combined with long sleep was associated with a higher total-to-HDL cholesterol ratio (e.g., 0.31 [0.12, 0.49] for low step counts). Short sleep combined with low step counts showed higher odds for hypertension and diabetes (1.34 [1.06, 1.69] and 1.98 [1.07, 3.68], respectively), while short sleep combined with either low or high MVPA had higher odds for diabetes (2.04 [1.09, 3.82] and 2.07 [1.04, 4.15], respectively). Conclusions: Low physical activity may exaggerate the detrimental associations between inadequate sleep with BMI, blood lipids, hypertension, and diabetes.