Twelve-Year Television Viewing Time Trajectories and Physical Function in Older Adults
The purposes of this study were to identify trajectories of older adults' television viewing (TV) time for 12 yr and to examine their associations with performance-based measures of physical function.Methods
Data on TV time (h·wk−1) and sociodemographic factors were collected at each assessment of the Australian Diabetes, Obesity and Lifestyle Study (1999/2000, 2004/2005, and 2011/2012), with objective measures of physical function (2.44 m timed up and go [TUG, s] and knee extensor strength [KES, kg] tests) collected at the final (2011/2012) assessment. Regression analyses examined predictors of trajectory membership and associations with TUG and KES in those 60+ yr of age in 2011/2012.Results
Six TV time trajectories were identified among the 1938 participants (age, 60–97 yr; 54% female): consistently low (9.7%), low-increasing (22.3%), moderate-decreasing (13.5%), moderate-increasing (30.3%), consistently high (18.9%), and high-increasing (5.2%). There were no statistically significant relationships with TUG (P > 0.05). In the fully adjusted model, KES performance was significantly better in the consistently low, low-increasing, and consistently high trajectories, compared with the moderate-increasing trajectory (P < 0.001, R2 = 0.33).Conclusion
Twelve-year trajectories of TV time were associated with muscle strength in older adults. These findings suggest that patterns of sedentary behavior can be a determinant of muscle strength in later life.