Daily steps and all-cause mortality: An umbrella review and meta-analysis.

OBJECTIVE: This study aimed to describe the variability in estimates of the association of daily steps and all-cause mortality in systematic reviews with meta-analyses, to identify the factors potentially responsible for it, and to provide an updated estimate. METHODS: Five databases were systematically searched up to May 2024 to identify systematic reviews with meta-analyses and prospective cohort studies. A qualitative synthesis of previous reviews and an updated meta-analysis of cohort studies were performed. Pooled hazard ratios (HRs) with their 95% confidence intervals (CIs) were calculated using a random-effects model. RESULTS: Eleven systematic reviews with meta-analyses and 14 cohort studies were included, revealing considerable variability in result presentation. Our updated meta-analysis showed a nonlinear association, indicating a lower risk of all-cause mortality with increased daily steps, with a protective threshold at 3143 steps/day, and a pooled HR of 0.91 (95% CI: 0.87, 0.95) per 1000 steps/day increment. Physical activity categories consistently indicated progressively reduced mortality risk, with the highly active category (>12,500 steps/day) exhibiting the lowest risk (0.35 (95% CI: 0.29, 0.42)). CONCLUSION: Systematic reviews and meta-analyses showed considerable variability in effect estimates due to different methods of quantifying exposure. Despite it, our study underscores the importance of increased daily steps in reducing all-cause mortality, with a minimum protective dose of 3000 steps/day, although the optimal dose differed according to age and sex. It is recommended that future studies categorise daily steps by physical activity category, perform dose-response analyses, and use increments of 1000 steps/day.

Steps per day and health-related quality of life in schoolchildren: the mediator role of cardiorespiratory fitness.

To analyse the relationship between steps per day and health-related quality of life (HRQoL) and cardiorespiratory fitness (CRF) and to examine whether the relationship between steps per day and HRQoL is mediated by CRF in schoolchildren. This was a cross-sectional study including 501 schoolchildren (aged 9-12 years, 47% girls), from Cuenca, Spain. Steps per day were measured using the Xiaomi Mi Band 3 Smart Bracelet, HRQoL was estimated by the KIDSCREEN-27 questionnaire, and CRF was assessed using the 20-m shuttle run test. Analysis of covariance and multivariate analysis of covariance models showed that children with a higher mean number of steps per day (> 9000 steps/day) had better HRQoL (global score, and physical and psychological well-being) and higher CRF levels than their peers with a lower number of steps per day (p < 0.05); however, these differences were no longer significant when controlling for sex, age, mother's education level, and CRF (p > 0.05). Linear regression models estimated that each 1000-step increment was associated with better CRF (ß = 0.350; 95% CI, 0.192 to 0.508). In addition, the relationship between steps per day and HRQoL was mediated by CRF (p < 0.05).    Conclusion: Steps per day are a good metric to estimate daily physical activity because of its positive relationship with CRF. Moreover, those children taking more than 9000 steps per day are associated with higher levels of physical and psychological well-being. Finally, a substantial part of the improvement in HRQoL achieved through the increase in physical activity (steps per day) is mediated by CRF. What is Known: • Physical activity is known to have a positive impact on health-related quality of life in children. Steps per day are commonly used as a measure of physical activity. • Cardiorespiratory fitness is a recognized indicator of overall health in youth. What is New: • Increments of steps per day were associated with better CRF, with a nonlinear association after approximately 9000 steps/day. • Schoolchildren with > 9000 steps/ day showed better HRQoL.

Physical activity is associated with lower mortality in adults with obesity: a systematic review with meta-analysis.

BACKGROUND: Obesity is a complex chronic disease associated with several adverse health outcomes that increase mortality risk. Physical activity (PA) is recommended for the prevention and treatment of obesity and is related to a decreased risk of cardiovascular disease, cancer and all-cause mortality. This systematic review and meta-analysis estimates the effect of PA levels on mortality (cardiovascular, cancer and all-cause mortality) in adults with obesity. METHODS: A systematic search was conducted in MEDLINE, Embase, Web of Science and SPORTDiscus from inception to June 2024. Prospective cohort studies that explored the association between PA and mortality in adults with obesity (according to their body mass index, ≥ 30 kg/m2) aged ≥ 18 years were included. Our main outcomes were all-cause mortality, and cardiovascular, and cancer mortality reported in primary studies by hazard ratios or relative risk, which were pooled for the meta-analysis when at least two studies reported the effect estimate for the same outcome. The PRISMA recommendations and the MOOSE guidelines were followed. The reported mortality risk estimates comparing insufficiently active versus active (moderate to very active) adults with obesity were pooled using the DerSimonian and Laird random-effects model. RESULTS: A total of 9 prospective cohort studies involving 199,425 adults with obesity (age range: 35-85 years) were included, of which 59,873 were insufficiently active and 84,328 were active. Active individuals had a 21% lower risk of all-cause mortality (HR: 0.79, 95%CI: 0.74 to 0.84; I2 = 38.2%), and a 24% lower risk of cardiovascular mortality (HR: 0.76, 95%CI: 0.66 to 0.87; I2 = 0.0%) than insufficiently active individuals. The HR for cancer mortality was 0.91 (95%CI: 0.80 to 1.02; I2 = 0.0%), and although this was mostly consistent with a benefit, it was based on only two studies. CONCLUSION: Our data support that moderate to high levels of PA are associated with a 21% lower risk of all-cause and 24% cardiovascular disease mortality in adults with obesity. Although data from the only two published studies seem to indicate a protective effect of PA on cancer risk, the estimates are not statistically significant. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022309346.

Effect of Vitamin D Supplementation on Fatigue in Multiple Sclerosis: A Systematic Review and Meta-Analysis.

Vitamin D supplementation has been considered a possible treatment to reduce the risk of disease activity and progression in people with multiple sclerosis (MS). However, its effect on disease symptoms remains unclear. The aim of this meta-analysis was to conduct a systematic review to assess the effect of vitamin D on fatigue in this population. The systematic review was conducted using the MEDLINE, Cochrane Library, Embase and Web of Science databases from inception to May 2023. Randomized controlled trials (RCTs) reporting pre-post changes in fatigue after vitamin D supplementation were included. Pooled effect sizes and 95% confidence intervals (95% CIs) were calculated by applying a random effects model with Stata/SE (Version 16.0; StataCorp., College Station, TX, USA). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. A total of five studies with 345 individuals (271 females; age range: 25.4-41.1 years) were included. A significant reduction in fatigue was perceived when vitamin D supplementation was compared with a control group: -0.18 (95% CI: -0.36 to -0.01; I2 = 0%). Thus, our findings show that the therapeutic use of vitamin D on fatigue in people with MS could be considered. Nevertheless, due to the lack of agreement on the dose to be applied, it is recommended to use it under medical prescription.