Television viewing time as a risk factor for frailty and functional limitations in older adults: results from 2 European prospective cohorts

BACKGROUND: Sedentariness is an important risk factor for poor health. The main objective of this work was to examine the prospective association between television viewing time and indicators of physical function, mobility, agility, and frailty. METHODS: Data came from two independent cohorts of community-dwelling older adults: the Seniors-ENRICA (n = 2392, 3.5 year follow-up), and the ELSA (n = 3989, 3.9 year follow-up). At baseline, television viewing and other sedentary behaviors were ascertained using interviewer-administered questionnaires. In the Seniors-ENRICA cohort overall physical function at baseline and follow-up was assessed using the physical component summary (PCS) of the SF-12 Health Survey. Measures for incident mobility and agility limitations in both cohorts were based on standardized questions, and incident frailty was measured with the Fried criteria. Analyses were adjusted for the main confounders, including physical activity at baseline. Results across cohorts were pooled using a random effects model. RESULTS: Lower (worse) scores in the PCS were observed among those in the highest (vs. the lowest) tertile of television viewing time (b-coefficient:-1.66; 95% confidence interval:-2.81,-0.52; p-trend = 0.01). Moreover, the pooled odds ratios (95% CIs) for mobility limitations for the second and third (vs. the lowest) tertile of television viewing were 1.00 (0.84, 1.20) and 1.17 (1.00, 1.38); p-trend = 0.12, respectively. The corresponding results for agility limitations were 1.18 (0.97, 1.44) and 1.25 (1.03, 1.51); p-trend = 0.02. Results for incident frailty were 1.10 (0.80, 1.51) and 1.47 (1.09, 1.97); p-trend = 0.03. No association between other types of sedentary behavior (time seated at the computer, while commuting, lying in the sun, listening to music/reading, internet use) and risk of functional limitations was found. CONCLUSIONS: Among older adults, longer television viewing time is prospectively associated with limitations in physical function independently of physical activity. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12966-017-0511-1) contains supplementary material, which is available to authorized users.