Comportamento sedentário, atividade física, dinapenia e mortalidade em idosos da comunidade

Abstract

Dynapenia characterized by a decline in muscle strength that exposes the elderly to a situation of increased vulnerability to frailty and mortality. The objectives of this study were: a) to evaluate the hypothesized effects of reallocation of time spent in sleep, sedentary behavior (SB), and moderate to vigorous intensity physical activity (MVPA), as the risk of dynapenia in community-dwelling elderly. b) to investigate the relationship of dynapenia with the risk of mortality by time exposed in sedentary behavior in community-dwelling elderly. Prospective cohort study, with five-year follow-up (2015 - 2020) of the Longitudinal Study of the Health of the Elderly in Alcobaça, Bahia (ELSIA), conducted with elderly aged 60 years or older, of both genders, from the urban area and registered in the municipality's Family Health Strategy. The elderly answered a structured questionnaire containing sociodemographic, health and behavioral information, and a physical performance test. The presence of dynapenia was assessed by handgrip strength test, with a cutoff point <27 kgf for men and <16 kgf for women. The International Physical Activity Questionnaire assessed MVPA and SB. Sleep was assessed by The Pittsburgh Sleep Quality Index. SB exposure time was also combined with dynapenia to construct 4 groups (no dynapenia and low SB; no dynapenia and high SB; presence of dynapenia and low SB; presence of dynapenia and high SB). Mortality was assessed by follow up time to death and/or censoring. For the data analyses, the isotemporal substitution model (10, 20, 30, 40, 50 and 60 minutes) was applied by logistic regression; and the hazard ratios for mortality by Cox proportional hazards models, with a significance level of 5%. In isotemporal replacement, replacing time in SB with MVPA showed a protective factor, with a 37.0% lower odds ratio for dynapenia (OR 0.63; 95% CI: 0.40-0.99). During the five-year follow-up of the study, 55 participants died. The elderly with dynapenia had higher risks for all-cause mortality (HR=2.16; 95% CI: 1.22 - 3.80) and when analyzing the combined SB dynapenia, the elderly with the worst behavior (high SB and presence of Dynapenia) had the risk ratios 2.35 times higher (95% CI 1.19- 4.65) when compared to the better behavior group. The elderly with Dynapenia have higher risks for all-cause mortality, worsening when the time exposed to SB increases.