Abdominal Obesity and Low Skeletal Muscle Mass Jointly Predict Total Mortality and Cardiovascular Mortality in an Elderly Asian Population

BACKGROUND: We investigated the combined impact of abdominal obesity and low skeletal muscle mass on cardiovascular and total mortality in an elderly Asian population. METHODS: A total of 1,485 elderly individuals (≥65 years) from Elderly Nutrition and Health Survey in Taiwan (1999-2000) were enrolled, and their survival status was followed using data from the National Death Registry. Skeletal muscle mass index (SMMI) was calculated by dividing skeletal muscle mass (kg) by height squared (m(2)). Low skeletal muscle mass was defined as the first quartile of SMMI. Abdominal obesity (high triglycerides plus waist circumference [HTGWC]) was defined as triglycerides ≥150mg/dL and waist circumference ≥90cm (men) and ≥80cm (women). The Cox proportional hazard model was used to evaluate the combined impact of abdominal obesity and low SMMI on cardiovascular and total mortality. RESULTS: During follow-up (median 9.2 years), one third (n = 493) of subjects died from any cause, of which 34% (n = 168) were cardiovascular-related. Total and cardiovascular mortality were 4.2 and 1.4 per 100 person-years, respectively. Low SMMI and HTGWC were independently associated with total mortality in men, but only low SMMI was significantly associated in women. Those with both HTGWC and low SMMI had the highest mortality risk, with the cardiovascular mortality risk increased by >6.8-fold and 3.2-fold in men and women, respectively, compared with controls having normal SMMI and TGWC. CONCLUSIONS: Elderly individuals with abdominal obesity and low skeletal muscle mass have higher all-cause and cardiovascular mortality risk.