Television watching, reading, cognition, depression and life satisfaction among middle-aged and older populations : a group-based trajectory modelling analysis of national data

This retrospective cohort study aimed to identify heterogeneous cognition, depression, and life satisfaction trajectory groups, and to examine the independent contributions of watching television and reading to these trajectories among middle-aged and older adults. A sample was taken from the Taiwan Longitudinal Study on Aging (TLSA) with measures of cognition, depression, life satisfaction, watching television, and reading during 12 years of follow-up (N = 4440). Group-based trajectory models and multinomial logistic regressions were used. The findings showed that the cohort was separated into three global cognition groups of low-cognition (n = 376), declining-cognition (n = 805), and maintained-cognition (n = 2718); three episodic memory groups of high-declining (n = 540), middle-stable (n = 2066), and improving groups (n = 1293); three depression groups of low-to-low (n = 2571), median-to-high (n = 960), and high-to-high groups (n = 368); and three life satisfaction groups of low- (n = 1133), middle- (n = 977), and high-level groups (n = 1789). Also, the findings demonstrated that after adjusting for covariates, those who did not watch television or read at the baseline had independently significantly increased odds of having lower global cognitive function, higher depression, and lower life satisfaction over time versus those who watched television or read almost every day. Based on the findings obtained, group-based trajectories of cognition, depression, and life satisfaction scores identified distinct subgroups among TLSA participants. Moreover, the findings suggest that healthcare providers need to develop more targeted population interventions to ensure successful aging. Healthcare providers can encourage older adults, particularly new retirees, to participate in leisure activities (i.e., watching television and reading) to reduce prevalence rates of cognitive impairment and depression.