Systematic review and meta-analysis on population attributable fraction for physical inactivity to dementia.

INTRODUCTION: The number of cases of dementia attributable to physical inactivity remains unclear due to heterogeneity in physical inactivity definitions and statistical approaches used. METHODS: Studies that used population-based samples to estimate the population attributable fraction (PAF) of physical inactivity for dementia were included in this review. Weighted PAFs were adjusted for communality among the risk factors (i.e., inactive persons may also share other risk factors) analyzed. Values were reported as percentage (%) of cases of dementia attributable to physical inactivity. RESULTS: We included 22 studies. The overall impact of physical inactivity, defined by any criteria, on dementia ranged from 6.6% (95% CI: 3.6%, 9.6%; weighted) to 16.6% (95% CI: 14.4%, 18.9%; unweighted). Studies using the WHO criterion for physical inactivity estimated a higher unweighted impact (ß = 7.3%; 95% CI: 2.0%, 12.6%) than studies using other criteria. DISCUSSION: Conservatively, one in 15 cases of dementia may be attributable to physical inactivity, defined by any criteria.

Leisure-Time Physical Activity May Attenuate the Impact of Diabetes on Cognitive Decline in Middle-Aged and Older Adults: Findings From the ELSA-Brasil Study.

OBJECTIVE: To assess leisure-time physical activity (LTPA) as a modifier of the diabetes/cognitive decline association in middle-aged and older participants in the Estudo Longitudinal de Saude do Adulto (ELSA-Brasil) study. RESEARCH DESIGN AND METHODS: ELSA-Brasil is a cohort of 15,105 participants (age 35-74 years) enrolled between 2008 and 2010. We evaluated global cognitive function, summing the scores of six standardized tests evaluating memory and verbal fluency, including the Trail-Making Test, at baseline and follow-up. Incident cognitive impairment was defined as a global cognitive function score at follow-up lower than -1 SD from baseline mean. Participants reporting ≥150 min/week of moderate to vigorous LTPA at baseline were classified as physically active. We assessed the association of LTPA with global cognition change in those with diabetes in the context of our overall sample through multivariable regression models. RESULTS: Participants' (N = 12,214) mean age at baseline was 51.4 (SD 8.8) years, and 55.5% were women. During a mean follow-up of 8.1 (SD 0.6) years, 9,345 (76.5%) inactive participants and 1,731 (14.1%) participants with diabetes at baseline experienced faster declines in global cognition than those who were active (ß = -0.003, -0.004, and -0.002) and those without diabetes (ß = -0.004, -0.005, and -0.003), respectively. Diabetes increased the risk of cognitive impairment (hazard ratio [HR] 1.71; 95% Cl 1.22, 2.39) in inactive but not in active adults (HR 1.18; 95% CI 0.73, 1.90). Among participants with diabetes, those who were active showed a delay of 2.73 (95% CI 0.94, 4.51) years in the onset of cognitive impairment. CONCLUSIONS: In adults living with diabetes, LTPA attenuated the deleterious association between diabetes and cognitive function.

Accelerometry Measured Movement Behaviors in Middle-Aged and Older Adults: Cross-Sectional Analysis of the ELSA-Brasil Study.

BACKGROUND: Little investigation of accelerometry assessed movement behaviors and physical inactivity was carried out in middle-aged and older adults in low-middle-income countries. OBJECTIVE: Describe accelerometry-measured movement behaviors and prevalence of physical inactivity in middle-aged and older adults. METHODS: We collected raw accelerometry data during the third visit (2017-2019) of ELSA-Brasil, a large-scale multicenter Brazilian cohort. Participants wore an ActiGraph wGT3X-BT on the waist for 24 hours for 7 days and documented sleep in a diary. RESULTS: Nine thousand two hundred and seventy-nine participants had valid data (73.4% of the eligible cohort). Overall activity was higher for men (11.82mg; 95% confidence interval [CI], 11.7 to 11.93) than women (10.69mg; 95% CI, 10.6 to 10.77) and lower in older groups-women (-0.12mg/y; 95% CI, -0.13 to -0.11), men (-0.16mg/y; 95% CI, -0.17 to -0.14). Participants were more active from noon to midnight. Distribution of movement behaviors varied with sex and age, and sleep duration was longer in older individuals. Overall, 14.4% (95% CI, 13.7 to 15.1) were inactive, with inactivity being more frequent in women (16.4%; 95% CI, 15.4 to 17.4) than men (12.2%; 95% CI, 11 to 13). Higher rates were observed in the oldest. Retirement was associated with a higher prevalence of physical inactivity in both sexes. CONCLUSION: Women were less active than men. Older individuals showed a high prevalence of physical inactivity, probably related to transition into retirement. These findings strengthen evidence for public policies promoting physical activity by emphasizing the need to target women, older individuals, and those transitioning to retirement to improve and/or maintain physical activity levels throughout the course of their lives.

The association of aerobic and muscular fitness with cognitive impairment: Findings from a nationally representative survey.

This study aimed to characterize the combined association between cardiorespiratory fitness (CRF), muscular strength, and cognitive outcomes in middle-aged and older adults from low and middle-income countries (LMICs). We analyzed cross-sectional, population-based data from adults aged 50 years or older from six LMICs. Mild cognitive impairment (MCI) was defined according to the National Institute on Aging-Alzheimer's Association criteria. Estimated CRF (eCRF) was calculated using previously validated, sex-specific equations. Handgrip strength (HS) was used as an indicator of muscular strength. We used linear and robust Poisson regression models to examine the associations between eCRF, HS, and MCI. Data from 28,339 adults (63.1 [9.5] years) were analyzed. Participants with low eCRF (PR: 1.45; 95%CI: 1.11, 1.90) and HS (PR: 1.92; 95%CI: 1.79, 2.04) were more prone to have MCI. Participants with low HS showed higher likelihood of MCI than those with preserved HS through the CRF range; however, this difference was not seen among highly fit individuals (10 METs or higher). Each 1-MET (PR: 0.77; 95%CI: 0.67, 0.86) and 5-kgf (PR: 0.63; 95%CI: 0.48, 0.79) increase was associated with a reduction in the likelihood of MCI. eCRF and HS were strongly and independently associated with MCI in middle-aged and older adults.

Association Between 24-Hour Movement Behavior and Cognitive Function in Brazilian Middle-Aged and Older Adults: Findings From the ELSA-Brasil.

Background and Objectives: The relationship between 24-hr movement behavior and specific domains of cognitive function is unclear. The purpose of this study was to identify the joint association of daily time spent in light (light-intensity physical activity [LPA]) and moderate-to-vigorous physical activity (MVPA), sedentary behavior (SB), and sleep with cognitive function in middle-aged and older adults. Research Design and Methods: Cross-sectional data from Wave 3 (2017-2019) of the Brazilian Longitudinal Study of Adult Health were analyzed. The study included adults aged 41-84 years old. Physical activity was assessed using a waist-worn accelerometer. Cognitive function was examined using standardized tests to assess memory, language, and Trail-Making test. Global cognitive function score was calculated by averaging domain-specific scores. Compositional isotemporal substitution models were performed to identify the association between the reallocation of time spent in LPA, MVPA, sleep, and SB with cognitive function. Results: Participants (n = 8,608) were 55.9% female (mean age 58.9 [8.6] years). Reallocating time from SB to MVPA was associated with higher cognitive function: Reallocating 15 min to MVPA by reducing 5 min from each other behavior was associated with increased odds of better cognitive function in both insufficient (<7 hr/day; odds ratio [OR]: 0.64; 95% confidence interval [CI]: 0.54-0.77) and sufficient (≥7 hr/day; OR: 0.62; 95% CI: 0.58-0.67) sleep groups. Among those with insufficient sleep, reallocating time to MVPA and sleep from SB was associated with higher global cognitive performance. Discussion and Implications: Small reductions in SB and increments in MVPA were associated with higher cognitive function in middle-aged and older adults.