Padrões de atividade física, comportamento sedentário, mortalidade e sobrevida em idosos.

Abstract

Physical activity (PA) and sedentary behavior (SB) have been constantly associated with health outcomes, including mortality, where one has been shown to be a protective factor for mortality risk and other risk factor, thereby causing changes in survival in the older adult’s population. However, there are still scientific gaps regarding the joint associations of these behaviors, and their associations are directly or mediated by other daily factors. The present work has three objectives: 1) Examine the effects of PA and SB in isolation and in combination on all-cause mortality. 2) Estimate the hypothetical effects of replacing the SB and PA time on the risk of mortality. 3) Evaluate the direct and indirect associations of PA and SB with survival time. This study is a population-based prospective cohort with a five-year follow-up (2015 - 2020), performed with older adults ≥ 60 years old, of both sex. The first two studies consisted of 332 older adults (59 deaths and 273 alive), and the third study was composed of 319 older adults (54 deaths and 265 alive). The older adults in the baseline of the study, answered a questionnaire structured in an interview form, containing sociodemographic, health and behavioral information and physical performance test. PA and SB were assessed using the international physical activity questionnaire. The older adults were dichotomized into sufficiently active and insufficiently active, and with low SB or high, when necessary, four combination are also built according to PA and SB. Three analysis techniques were used for each objective. For the initial two, Cox proportional hazards regression was applied. adding the second of isotemporal substitution modeling, to test hypothetical behavioral changes, both had a 95% confidence interval and hazard ratio estimate. To answer the third objective, path analysis was used, and trajectory diagrams were created to represent the hypothetical initial model and the final model of the present study. Regarding the first objective, it was identified that being insufficiently active is a risk factor for mortality, however, SB time did not show associations with the outcome. When observing the combination, individuals who are insufficiently active and have a long SB experience had a higher chance of mortality, SB being a potential of risk. In the second objective, a reduction in the risk of mortality was identified when reallocating the SB, ranging in reductions between 10% to 46% in the risk of mortality. As for objective three, it was found that PA has indirect associations with survival time, being mediated by instrumental activities of daily living (IADL) and the Short physical performance battery (SPPB), SB time was mediated by IADL, SPPB, number of hospitalizations and medications. The explanatory model explains the survival time in 19%. Our study shows that PA and SC have associations with the risk of mortality, however, these behaviors may be mediated by other factors.