Establishment of muscle mass diagnostic standard of sarcopenia using a bioelectrical impedance analysis and epidemiological investigation of the elderly in Shanghai

Abstract

Objective To establish diagnostic standard of sarcopenia using bioelectrical impedance analysis (BIA) and to obtain the prevalence of sarcopenia in the elderly in Shanghai. Methods 40 volunteers aged 20-77 years were enrolled and received BIA and dual-energy X-ray absorptiometry (DEXA) measurements in order to verify the reliability of BIA for measuring lean mass. 219 healthy young volunteers aged 20 to 40 years with ratio of gender men: women 100: 119 had BIA measurements to obtain peak muscle mass and sarcopenia diagnostic cut-off point of the elderly. 657 elderly aged ≥ 60 years with ratio of gendermen: women 318: 339 took BIA measurements to obtain the prevalence of sarcopenia in the elderly in Shanghai. Results No statistical difference between BIA-measured and DEXA-measured LM was observed (P=0.307). The appendicular skeletal muscle mass/height2 (ASM/h2) was (7.90±0.62) kg/m2 in young men, and (6.12±0.44) kg/m2 in young women, the cut off in elderly men and women were ≤6.66 kg/m2 and ≤ 5.24 kg/m2 respectively. Elderly people were divided into three age groups: aged60-69 years group, aged 70-69 years group, aged ≥ 80 years group, The prevalence of sarcopenia were 14.6%, 25.0% and 36.0% in men and 6.8%, 12.6% and 27.9% in women in aged 60-69 years, aged 70-69 years, aged ≥ 80 years groups, respectively. The overall prevalence in elderly men and women were 23.6% and 11.8% respectively. Conclusions Measurement of LM by BIA is validated in Shanghai volunteers. The prevalence of sarcopenia in the elderly is increased with age, which is higher in elderly men than in elderly women. Key words: Muscular diseases; Electric impedance; Body composition