Comparison of field- and laboratory-based estimates of muscle quality index between octogenarians and young older adults: an observational study
Dahan da Cunha Nascimento, Jonato Prestes, Joyce de Sousa Diniz, Pedro Rodrigues Beal, Vicente Paulo Alves, Whitley J. Stone, Fabiani Lage Rodrigues Beal
Abstract
Muscle quality (the ratio of strength to lean muscle mass) might be a better indicator of muscle function than strength alone. Differences in muscle quality index (MQI) between octogenarians and young older adults remain unclear. The aims of the present cross-sectional study were to compare (1) MQI between octogenarians and young older adults, (2) lab versus field-based MQI tools, and (3) determine possible confounding factors affecting MQI in older adults. Compiled data from two cross-sectional studies included 175 younger and older adults (31 men and 144 women) with a mean age of 75.93 9.49 years. Participants with age 80 years old were defined as octogenarians (n= 79) and < 80 years was defined as young older adults (n= 96). Laboratory MQI was derived from the ratio of grip strength to arm muscle mass (in kg) mea-sured by dual-energy x-ray absorptiometry. Field-based MQI was quantified from the ratio of grip strength to body mass index (BMI). Octogenarians displayed lower field (P= 0.003) and laboratory MQI (P< 0.001) as compared with young older adults. There was a strong correlation effect between field MQI and laboratory MQI (P= 0.001, R= 0.85). BMI (P= 0.001), and diabetes mellitus (P= 0.001) negatively affected MQI. Women presented lower MQI (P= 0.001) values than men. In light of this information, rehabilitation specialists should consider the use of fieldbased MQI as a tool for evaluation and follow-up of older population.