Prevalence of sarcopenia among healthy ambulatory subjects: the sarcopenia begins from 45 years.

Background And Aims: Sarcopenia has been indicated as a reliable marker of frailty and poor prognosis among the oldest individuals. There are only few data on sarcopenia in healthy general population. We evaluated the prevalence of sarcopenia and its association with functional and clinical status in a population of healthy ambulatory subjects over 45 years living at home, in Paris (France).

Methods: This study was conducted selecting all ambulatory participants (n = 1,445) aged 45 years and older from October 2008 to September 2011, consulting in the Institute of Physiology (Institut de Jaeger) from Paris (France) for a functional and muscular evaluation, and did not have limitations to moderate physical exercise. All were healthy people. All subjects performed a medical examination, associated with evaluation of muscle mass (body composition assessment using dual-energy X-ray absorptiometry) and of muscle function (by hand grip strength). Diagnosis of sarcopenia required the documentation of low muscle mass with low muscle strength according to the current international consensus definition of sarcopenia.

Results: From 1,421 participants (553 males and 868 females) definitively enrolled, 221 subjects (135 females and 86 males) (15.5 %) were identified as sarcopenic. Results from multivariate logistic regression models showed that sarcopenia was inversely associated with BMI with those participants with BMI higher than 22 kg/m(2) showing a lower risk of sarcopenia relative to those with BMI less than 21 kg/m(2) (OR 0.72; 95 % CI 0.60-0.91). Similarly, probability of sarcopenia was lower among subjects involved in leisure physical activities for 3 h or more per week (OR 0.45; 95 % CI 0.24-0.93). According to the category of age [45-54; 55-64; 65-74; 75-84 and 85 years or more], the prevalence of sarcopenia in women increase from 9.1; 12.7; 14.5; 19.4; to 33.3 %, respectively. For the men, the percentage of sarcopenia increase with aging from 8.6; 15.6; 13.6; 63.8 to 45.5 %, respectively.

Conclusions: The present study suggests that among healthy ambulatory subjects over 45 years living at home, sarcopenia is frequent, even to the youngest subjects of the studied population, taking place from 9 % from 45 years, until 64.3 % for the subjects over 85 years. Our findings support the hypothesis that muscle mass and function are associated with BMI and physical activity, whatever the age of the subject.