In older Brazilian adults, reduction in LS mobility during the pandemic was more frequent among older people of gender female, 70 or more age, with multimorbidities, pain, limitation in daily living activities and decreased levels of walking, even after adjustment for confounding factors. The estimated marginal means, and mean differences and mean change for each associated factor in the four waves analysis shows decreased life-space mobility according to these caractheristics, reinforcing hypothesis that guided this study. This study demonstrated the LS mobility of older people, during pandemic period, was dramatically reduced and was not recovered even after the relaxation of social restriction measures. It should be noted that such life-space mobility is measures of actual real-world mobility and are gaining increased attention as an important indicator of healthy ageing [29].
The results of this study, align with our hypothesis since, even after widespread vaccination campaigns and a relaxation of social restriction laws in Brazil, the decrease in living space mobility that harmed COVID-19 during pandemic did not recover to pre-pandemic levels. We observed a gradual but slight increase over time among all groups, except among women, those aged ≥ 80 and 70–79 years, with multimorbidity, pain, functioning limitations, and poor levels of walking. Life-space conceptual framework can be used to analyze the mobility transitions, particularly its relationship with environmental conditions. Furthermore, tracking life-space mobility can help the understanding of how older people relate to changes in their health status and social roles over challenging periods of their lifespan [2, 22].
Although mobility has affected the entire worldwide population, there are few studies about mobility restriction patterns during the pandemic. To comprise the effect of restriction measures on mobility was a challenging task globally because of different lockdown policies. Governments were more likely to impose social restriction measures when mortality rates were higher and lessen policies when the situation seemed in control. However, these policies were less likely to affect older people living in different parts of the world. Compared to the period before the COVID-19 lockdown, there was a consistent and moderate decline in the life-space mobility in Finland [5] and a drop of 50 to 79% in Brazil [6], with or without association SARS-COV-2 diagnosis [30]. Only Browne and cols. compared mobility scores over one year during the pandemic and found a significant increase in LSA score (at apartment/ row house, but not detached house) among older adults with hypertension living in Natal (Brazil). The reason for this result is supposed to be the effect of COVID-19 vaccination [31].
Despite the similarities in the change mobility score found, a possible difference between these studies and ours includes the analysis period, for which all studies has been analyzed up to the first year of the pandemic. Other difference refers to a small sample [31] and the disparity in coping with the pandemic in each country, according to summarize of the World Health Organization (WHO, 2023 – https://www.who.int/europe/emergencies/situations/covid-19).
Notwitstanding the results of specific LS mobility observed in this study have not been reported in others studies, hypotheses for explaining the results are based on the multicausal conception of mobility among older adults. Specially during the pandemic period, this conception involve direct and indirect pathways: i) the acute triggering of worldwide social restriction measures, as a social distancing and stay-at-home orders and reduced opportunities for several out-of-home activities, and ii) the changes in musculoskeletal architecture related to inflammatory COVID-19 profile.
First, public health recommendations for quarantine and self-isolation restricted physical activity and exacerbated the decline in mobility and physical function [4, 32]. We explore if older adults of different age groups respond differently to life-space mobility. Because COVID-19 poses much more significant risks for older people, it could be expected greater respect for isolation measures by these people due to the greater likelihood of risk when infections waves rise. On the way, the analysis shows that the oldest reduces mobility even more strongly. This scenario is consistent with survey-level evidence presented by Perracini et al. [4], indicating that the oldest old might be overwhelmed by the fear of contracting and dying from COVID-19. The recent work by Tison et al. [33] analyzed lasting global changes in physical activity patterns assessed through step counts. They compared one-year tracks and observed that the average daily steps globally fell below 4,000. According to the authors, the most significant recovery in steps per day occurred in 2021 (4997 steps per day) but was still 10% lower than pre-pandemic levels. The mean step count for the end of data collection (2022) remained significantly lower, although there was significant pattern variation. Two years after COVID-19 was declared a pandemic, the world continues to take fewer steps per day, even though lockdowns and social distancing have not been a part of daily life for some time [33].
The second hypothesis, the possible pathway in other research suggests coronaviruses can cause systematic inflammation [34]. Supported by this hypothesis, a study showed that SARS-CoV-2 may act as an adjunct in clinical conditions of muscle weakness and explain the subsequent mobility impacts [35, 36, 37], which corroborates the understanding of traditional risk factors concerning mobility restriction among older adults after COVID-19. Some evidence suggests that SARS-CoV-2 can cause neuroinflammation and inflammation in other parts of the body, resulting in neuronal degeneration and release of proinflammatory cytokines, which may explain the subsequent chronic fatigue and functional mobility impacts experienced by many individuals after COVID-19 [35, 36, 37]. Unfortunately, this hypothesis could not be tested in our study, first because we do not know who actually had COVID-19. Furthermore, even those who had it, we do not know if the disease affected the musculoskeletal architecture, although there is a biological plausibility indicated in the literature.
The longitudinal analyses LS mobility, especially during pandemic period, in older population is still incipient. The results of this study contribute to a more detailed understanding of the impact of mobility restriction and multifactors determinants, supporting the development of future studies, which should monitor a greater diversity of groups.
The results of the present analysis have some limitations, such as information bias, due to the difficulty of older people to remember mobility in the last month, which does not seem to have influenced the estimates, considering the frequence found in this study was similar to that of other studies. The same, there was a 44.4% sample loss rate during follow-up, but with no statistical difference between the groups, which demonstrates homogeneous loss, common among cohort studies. This analysis was conducted during period with high Fake News wave in older population and in a sample with high difficult technology (smartphone use), which may explain the reduction in their participation. On the other hand, the information were collected through standardized instruments, besides having included a wide range of cities Brazilians.