Association of regional muscle strength with mortality and hospitalisation in older people

Abstract

Background: the association between muscular strength, mortality and hospitalisation with ageing can change depending on sex and the body region analysed (e.g. upper and lower limb muscles).

Objective: to determine the effect of measuring lower and upper extremities muscular strength on the relationship between strength, mortality and hospitalisation risk in elder men and women.

Design: a population-based cohort study using data from the Toledo Study for Healthy Aging (TSHA).

Methods: a Spanish population sample of 1,755 elders aged ≥65 years participated in this study. Upper (handgrip and shoulder) and lower limbs (knee and hip) maximal voluntary isometric strength was obtained using standardised techniques and equipment. Cox proportional hazards model was used to examine mortality and hospitalisation over 5.5 and 3 years of follow-up, respectively.

Results: after adjustment for potential confounding factors, including co-morbidities and BMI, hazard ratio of death and hospitalisation was significantly lower in the stronger women and men, but showing regional- and sex-specific differences. That is shoulder, knee and hip muscle regions in women and handgrip and shoulder in men (all P < 0.05). There was a cumulative effect of measuring several muscle strengths over the risk of health events (P < 0.05), so that mortality hazard ratio increased by 45% in women and 25% in men per muscular strength (shoulder, grip, knee and hip) in the weaker strength quartile increase (P < 0.01).

Conclusions: regional muscle strength is a predictor of medium-term mortality and hospitalisation in elder men and women. Multiple strength measures including lower and upper body limb muscles are better predictors than a single strength measurement.

Keywords: ageing; death; hospitalisation; older people; regional muscle strength; sex.