Muscular Strength as a Predictor of All-Cause Mortality in an Apparently Healthy Population: A Systematic Review and Meta-Analysis of Data From Approximately 2 Million Men and Women

Objectives: The aims of the present systematic review and meta-analysis were to determine the relationship between muscular strength and all cause mortality risk and to examine the sex-specific impact of muscular strength on all-cause mortality in an apparently healthy population. Data Sources: Two authors systematically searched MEDLINE, EMBASE and SPORTDiscus databases and conducted manual searching of reference lists of selected articles. Study Selection: Eligible cohort studies were those that examined the association of muscular strength with all-cause mortality in an apparently healthy population. The hazard ratio (HR) estimates with 95% confidence interval (CI) were pooled by using random effects meta-analysis models after assessing heterogeneity across studies. Data Extraction: Two authors independently extracted data. Data Synthesis: Thirty-eight studies with 1,907,580 participants were included in the meta-analysis. The included studies had a total of 63,087 deaths. Higher levels of handgrip strength were associated with a reduced risk of all-cause mortality (HR = 0.69; 95% CI, 0.64-0.74) compared with lower muscular strength, with a slightly stronger association in women (HR = 0.60; 95% CI, 0.51-0.69) than men (HR=0.69; 95% CI, 0.62-0.77) (all P<.001). Also, adults with higher levels of muscular strength, as assessed by knee extension strength test, had a 14% lower risk of death (HR=0.86: 95% CI, 0.80-0.93; P<.001) compared with adults with lower muscular strength. Conclusions: Higher levels of upper- and lower-body muscular strength are associated with a lower risk of mortality in adult population, regardless of age and follow-up period. Muscular strength tests can be easily performed to identify people with lower muscular strength and, consequently, with an increased risk of mortality. (C) 2018 by the American Congress of Rehabilitation Medicine