Adequate Muscular Strength May Help to Reduce Risk of Residual-Specific Mortality: Findings From the National Health and Nutrition Examination Survey

Abstract

Objective: Muscular strength has been shown to inversely associate with mortality. The purpose of this study was to examine the association between muscular strength and residual-specific mortality among a national sample of US adults, which has yet to be investigated. Here, residual-specific mortality is identified as deaths not inclusive of the 9 leading causes of death as identified by the International Classification of Diseases, 10th revision.

Methods: Data from the 1999-2002 National Health and Nutrition Examination Survey were used (N = 2171 adults, aged 50-85 y). Participants were followed through 2011, including a median follow-up of 125 months. Lower extremity muscular strength was assessed using maximal isokinetic contractions.

Results: After adjusting for all covariates (age, gender, race/ethnicity, body mass index, C-reactive protein, mean arterial pressure, self-report of meeting aerobic-based physical activity guidelines, and physician diagnoses of diabetes), the Cox proportional hazard model demonstrated that for every 25 N increase in lower extremity muscular strength, individuals had a 14% reduced risk of residual-specific death (hazard ratio = 0.86; 95% confidence interval, 0.78-0.96; P = .008).

Conclusion: Lower body muscular strength is inversely and independently associated with residual-specific mortality risk, underscoring the importance of adequate muscular strength to prolong survival.

Keywords: NHANES; epidemiology; physical activity; survival.