Prospective association of TV viewing with acute phase reactants and coagulation markers: English Longitudinal Study of Ageing

Objective: Inflammatory processes are putative mechanisms underlying the detrimental health effects of sedentary behaviour but no long-term prospective data are available. We examined the longitudinal association between TV viewing, physical activity and inflammatory markers over a 4-year follow-up period. Methods: Participants were 3612 men and women (mean age 64.1±8.2 years) from the English Longitudinal Study of Ageing. Self-reported daily TV viewing was measured at baseline and 2 years follow up. Inflammatory markers (serum high-sensitivity C-reactive protein [CRP], white blood cell count [WBC], and fibrinogen) were measured at baseline (2008/09) and 4 years follow-up (2012/13). Results: On average, participants viewed TV for 5.1±4.0h/d, and there was an increase of 1.9h/wk TV viewing over 2 years. In linear models adjusted for covariates including physical activity, TV viewing was not associated with log_eCRP at follow-up (B=0.004, 95% CI, -0.001, 0.009, p=0.09) but was associated with WBC (B=0.018, 95% CI, 0.005, 0.031, p=0.006), and fibrinogen (B=0.004, 95% CI, 0.00, 0.008, p=0.035). In contrast, physical activity was inversely associated with CRP (p=0.047) and WBC (p=0.026), but not fibrinogen (p=0.22). An increase in TV viewing (of at least 1h/d) was associated with higher concentrations of CRP (p=0.015) and WBC (p=0.05) at follow up after adjustment for covariates and baseline TV viewing. Conclusions: Physical activity and sedentary behaviour have contrasting associations with markers of low grade inflammation over 4 years of follow-up. These behaviours may be important in influencing the pro-inflammatory state seen with ageing.