Search

Introduction: The association of light‐intensity physical activity (LPA) with mortality is poorly understood. This meta‐analysis of cohort studies aimed to examine the dose‐response relationships between daily device‐measured LPA and mortality in adults aged 18 or older and to explore whether the associations were independent of moderate‐to‐vigorous physical activity (MVPA). Methods: Searches for prospective cohort studies providing effect estimates of daily LPA (exposure) on all‐cause mortality (outcome) were systematically undertaken in electronic databases up to April 30, 2019. Subgroup analyses and meta‐regression analyses with random‐effects models were performed to quantify the dose‐response relationships between daily LPA and mortality. Sensitivity analyses were also conducted to assess the stability of the results. Results: A total of 11 studies were included in the meta‐analysis. Analyses contained 49 239 individuals (mean age 60.7, SD = 13.6) who were followed up for a mean 6.2 years (2.3‐14.2 years), during which 3669 (7.5%) died. In comparison with the reference group (<3 h/d), the pooled HRs (and 95% CIs) of mortality were 0.71 (0.62‐0.82), 0.68 (0.59‐0.79), 0.56 (0.44‐0.71) for groups 3 to <5 h/d, 5 to <7 h/d, and more than 7 hours a day LPA, respectively. Meta‐regression models indicated that there was a log‐cubic dose‐response relationship between daily LPA and mortality in adults and older people, independent of MVPA. Conclusions: Time spent in daily LPA was associated with reduced risks of mortality in adults and older people. These data support the inclusion of LPA in the future physical activity guidelines. [ABSTRACT FROM AUTHOR]

Background: This meta-analysis aimed to estimate the shape of the dose-response association between objectively-assessed daily sedentary time (ST) and all-cause mortality, and to explore whether there is a threshold of ST above which there is an increase in mortality risk in older adults. Methods: Searches for prospective cohort studies providing effect estimates of daily ST (exposure) on all-cause mortality (outcome) were undertaken in five databases up to 31 March 2019. A random-effects meta-regression model was conducted to quantify the dose-response relationship between daily ST and all-cause mortality. Sensitivity analyses were also performed to test the stability of the results. Results: Our analysis of pooled data from 11 eligible studies did not reveal a consistent shape of association between ST and mortality. After excluding three studies with potential confounding bias, there was a log-linear dose-response relationship between daily ST and all-cause mortality. Overall, higher amounts of time spent in sedentary behaviors were associated with elevated mortality risks in older adults. Visual assessments of dose-response relationships based on meta-regression analyses indicated that increased mortality risks became significant when total ST exceeded approximately 9 h/day. Conclusions: Based on a limited number of studies, this meta-analysis provides a starting point for considering a cut-off of daily sedentary time, suggesting older adults spend less time in daily sitting. [ABSTRACT FROM AUTHOR]

Background: The appropriate limit to the amount of daily sedentary time (ST) required to minimize mortality is uncertain. This meta-analysis aimed to quantify the dose-response association between daily ST and all-cause mortality and to explore the cut-off point above which health is impaired in adults aged 18-64 years old. We also examined whether there are differences between studies using self-report ST and those with device-based ST.Methods: Prospective cohort studies providing effect estimates of daily ST (exposure) on all-cause mortality (outcome) were identified via MEDLINE, PubMed, Scopus, Web of Science, and Google Scholar databases until January 2018. Dose-response relationships between daily ST and all-cause mortality were examined using random-effects meta-regression models.Results: Based on the pooled data for more than 1 million participants from 19 studies, the results showed a log-linear dose-response association between daily ST and all-cause mortality. Overall, more time spent in sedentary behaviors is associated with increased mortality risks. However, the method of measuring ST moderated the association between daily ST and mortality risk (p < 0.05). The cut-off of daily ST in studies with self-report ST was 7 h/day in comparison with 9 h/day for those with device-based ST.Conclusions: Higher amounts of daily ST are log-linearly associated with increased risk of all-cause mortality in adults. On the basis of a limited number of studies using device-based measures, the findings suggest that it may be appropriate to encourage adults to engage in less sedentary behaviors, with fewer than 9 h a day being relevant for all-cause mortality. [ABSTRACT FROM AUTHOR]