Ageing, adiposity indexes and low muscle mass in a clinical sample of overweight and obese women

Summary Objective Ageing is associated with a progressive decline in the quantity (mass) and quality (function) of the muscular tissue. To assess the prevalence of low muscle mass (LMM) alone and in combination with high adiposity (LMM-HA) in a clinical representative sample of adult women and to determine how the prevalence of (LMM-HA) changes using different adiposity indexes. Methods 763 overweight and obese women (age range: 18–87 years) attending a weight loss clinic. Weight, height, and waist circumference (WC) were measured and BMI calculated. Bioelectrical impedance (BIA) was used to measure fat mass (FM). Skeletal muscle index (SMI) was used for the diagnosis of LMM. Adiposity indexes (BMI, WC, FM%, FM index) were combined with SMI to assess the prevalence of LMM-HA. Results The prevalence of LMM was 27.4% in women older than 60 years. Established cut-off scores for excess adiposity determined differences in the prevalence of LMM-HA. The lowest was observed using the BMI derived cut-off score (≥30 kg/m2 ), with FM% (≥35%) the most inclusive, classifying more than 90% of sarcopenia cases as LMM-HA. Conclusions The prevalence of LMM-HA is different between anthropometric (BMI, WC) and bioimpedance measures (FM% and FMI) of adiposity. The sensitivity of the adiposity indexes for the diagnosis of sarcopenic obesity and its impact on the prediction of cardio-metabolic diseases remain to be tested.