Cross-sectional associations of device-measured sedentary behaviour and physical activity with cardio-metabolic health in the 1970 British Cohort Study

Aims This study aimed to examine the cross-sectional associations of thigh accelerometry-assessed sedentary behaviour and moderate-to-vigorous physical activity (MVPA) with cardio-metabolic health markers and prevalent diabetes in a population sample of middle-aged British adults. Methods Participants (n = 4892) from the age-46-to-48 wave of the 1970 British Cohort Study were fitted with a waterproofed activPAL3 micro device. Total/prolonged sedentary time, breaks and MVPA were the main exposures. We dichotomized prolonged sedentary time and MVPA based on the corresponding median, generating four combinations as categorical exposures. Outcomes comprised of diabetes and seven cardio-metabolic health markers. We used logistic regression and generalized linear models to examine independent/joint associations, conducting a minimally adjusted model including demographics and contextual covariates, and further adjusted for total sedentary time and/or MVPA as applicable. Results Each set of 10 sedentary breaks and 1 h of prolonged sedentary time were associated with HbA(1c)(mmol/mol) [B = -0.18 (-0.33, -0.03) and 2.35 (1.01, 3.69), respectively]. Each set of 10 sedentary breaks and 1 h of MVPA were favourably associated with diabetes [adjusted odds ratio (AOR): 0.80 (0.71, 0.99) and 0.42 (0.26, 0.67), respectively]. Joint analyses showed that only the low MVPA x long sedentary time combination had significantly higher odds for diabetes than the referent high MVPA x short sedentary time combination [AOR: 1.89 (1.17, 3.03)]. Conclusions Each set of additional 10 sedentary breaks per day was associated with 20% lower odds for diabetes. A low physical activity level combined with long sedentary time might synergistically deteriorate cardio-metabolic health.