Dynapenic Abdominal Obesity as a Risk Factor for Falls

BACKGROUND: Obesity and low muscle strength (dynapenia) are independently associated with greater falls risk. It remains unclear whether dynapenia and obesity have an additive effect on falls risk, greater than either phenotype alone. OBJECTIVES: To determine whether a combination of abdominal obesity with dynapenia, dynapenic abdominal obesity (DAO), confers a greater risk of falls than either obesity or dynapenia alone in both men and women. DESIGN: An observational cohort study was conducted. Setting and Participants: Data from English adults (n=4239, 60-87 years) who took part in the English Longitudinal Study of Ageing were included. Measurements Dynapenia, was defined as hand-grip strength <20kg (female), <30kg (male). Abdominal obesity was defined as waist circumference >88cm (female), >102cm (male). Data on falls and fall-related injuries over a 2-year follow-up were collected. Multiple logistic regression analyses were performed adjusting for age and sex, with results expressed as odds ratios (OR) and areas under the receiver operating characteristic curve (AUC). RESULTS: Falls occurred in 1049 participants, with 284 reporting a related injury during follow-up. DAO was associated with greater OR of falls in men (OR 2.1, 95% Confidence Intervals (CI) 1.3-3.2). Dynapenia rather than obesity was associated with falls in women, with greatest OR observed in those with low hand-grip strength (OR 1.4, 95% CI 1.1-1.7). Individual discrimination was low for measures of obesity or dynapenia either alone or in combination (AUC 0.51-0.58). There was no relationship between fall-related injuries and obesity or dynapenia. CONCLUSION: Our findings suggest a synergistic effect of obesity with dynapenia on falls risk in men but not women.