Aims/hypothesis: Little research has been done on the long-term longitudinal associations between markers of sedentary behaviour and health risks. We hypothesised that television (TV) viewing in early to mid-adulthood predicts an adverse cardiometabolic risk factor profile in middle age independently of participation in physical activity.
Methods: We used prospective data from 5,972 (2,947 men) participants of the 1958 British Birth Cohort study. TV viewing and exercise frequency were obtained at age 23 years. Daily TV viewing and weekly moderate to vigorous physical activity were assessed at age 44 years, as well as HbA(1c), triacylglycerol, total and HDL-cholesterol, systolic and diastolic blood pressure, and waist circumference. We used generalised linear models and multiple linear regression to examine the associations between TV viewing at age 23 years and the cardiometabolic risk markers (including a clustered cardiometabolic risk score) at 44 years, while adjusting for sex, exercise participation and TV viewing at age 44 years, and other potential confounders.
Results: In the multivariable models, TV viewing frequency at age 23 years showed positive associations with C-reactive protein (generalised linear model change 12.6%, 95% CI 3.5, 22.8; p = 0.005), fibrinogen (change 1.8%, 95% CI 0.3, 3.3; p = 0.020), waist circumference (coefficient 1.17, 95% CI 0.32, 2.01; p = 0.004), systolic (coefficient 1.44, 95% CI 0.33, 2.54; p = 0.019) and diastolic (coefficient 0.75, 95% CI -0.01, 1.51; p = 0.053) blood pressure, and clustered cardiometabolic risk score (men only, coefficient 0.06, 95% CI 0.01, 0.11; p = 0.038). Adjustments for baseline (age 23 years) BMI attenuated these associations towards null.
Conclusions/interpretation: TV viewing habits in early adulthood are associated with adverse cardiometabolic profiles in early middle adulthood that are independent of TV viewing habits and physical activity in middle age, but not independent of BMI in early adulthood.