Independent and Joint Associations of Sedentary Behavior and Physical Activity with Cardiometabolic Health Markers in the 1970 British Birth Cohort

Objective To examine the independent and joint associations thigh-worn accelerometry assessed sedentary time and moderate to vigorous physical activity with cardiometabolic health markers. Design Cross-sectional study embedded in the age-46 wave an established birth cohort, the 1970 British Birth Cohort. Setting Population-based sample from Great Britain (England, Scotland, and Wales). Methods Outcome measures included: body mass index, waist-to-hip ratio, blood pressure, glycated hemoglobin, high-density lipoprotein cholesterol, total cholesterol, triglycerides, and c-reactive protein. Sedentary behavior and other physical activity exposures, recorded by a thigh-worn activPAL3 accelerometry, included: daily sedentary time, breaks in sedentary time, daily time spent in moderate-to-vigorous physical activity. Multiple linear regression analyses, multiple logistic regression analyses, and general linear models were conducted as applicable. Results 4,634 participants were available for the final analysis. After adjusting for potential confounders and moderate-to-vigorous physical activity, daily sedentary time was positively associated with triglycerides (β=0.052 [0.015, 0.089]) and inversely associated with high-density lipoprotein cholesterol (β=-0.015 [-0.022, -0.010]). Daily prolonged sedentary time (≥ 60 minutes) was positively associated with both glycated hemoglobin and log-transformed c-reactive protein (β=0.240 [0.030, 0.440] and 0.026 [0.007, 0.045], respectively) and inversely associated with systolic blood pressure and high-density lipoprotein cholesterol (β=-0.450 [-0.760, -0.150] and -0.013 [-0.022, -0.003], respectively). After adjusting for potential confounders and daily sedentary time, daily breaks in sedentary time were inversely associated with glycated hemoglobin (β=-0.020 [-0.037, -0.003]), and positively associated with both triglycerides and systolic blood pressure (β=0.006 [0.002, 0.010] and 0.030 [0.002, 0.050], respectively). The joint associations of prolonged sedentary time and moderate-to-vigorous physical activity with the prevalence of diabetes were not statistically significant. Conclusion Prolonged sedentary time (≥ 60 minutes) and daily breaks in sedentary time were deleteriously associated with glycated hemoglobin, although we found no evidence that there were joint moderate-to-vigorous physical activity and sitting associations.