Study on the changes in muscle mass in elderly people of different ages in Hangzhou / 中华老年医学杂志

ABSTRACT

Objective To investigate the changing characteristics of muscle mass by dual energy X-ray absorptiometry (DEXA) in middle aged and elderly people with different ages.Methods This study included 343 healthy people aged 50-89 years (178 males and 165 females).Subjects were divided into 4 groupsaged 50-59,60-69,70-79,and 80-89 years group.Fat-free body mass (FFM),the appendicular lean body mass (aLM),trunk lean mass (tLM) were measured by DEXA.The aLM/body weight (Wt％) and aLM index (ASMI) were calculated by DEXA.Results The tLM in both gender was decreased in aged 80-89 years group than in aged 50-59 years group [male (10.6± 1.8) kg vs.(18.4±2.9) kg,female (7.1±1.2) kg vs.(14.8±2.1) kg,F=5.7 and 7.8,P＜ 0.01].The average ASMI in both gender was decreased in aged 70-79 and 80-89 years groups than in aged 50-59 years groups [male (5.5±0.4) kg/m2,(4.9±0.7) kg/m2 vs.(6.1±0.5) kg/m2,female (4.3±0.4) kg/m2,(3.9±0.5) kg/m2 vs.(4.8±0.6) kg/m2,F=24.9 and 9.6,both P＜0.01].The quality of muscle mass was decreased with aging in the elderly.Conclusions Ageing is an important risk factor for sarcopenia in the elderly.DEXA can be used to evaluate the muscle mass in middle aged and the elderly,and ASMI can be used as a reliable measurement index.