Background: Sarcopenia is the progressive loss of mass and skeletal muscle strength and has serious consequences on older people's health. The Chilean older population has a high life-expectancy, but the prevalence of functional dependence is also high.
Objective: To determine the prevalence of sarcopenia in Chilean older adults and its relationship with age, gender, and body mass index (BMI).
Design: Cross-sectional study.
Setting: Community.
Participants: 1,006 non-disabled, community-dwelling subjects aged 60 years or older living in Santiago.
Measurements: Anthropometric measurements, handgrip strength, physical performance tests, and dual-energy-x-ray-absorptiometry (DXA) scan were performed. Sarcopenia was defined using the algorithm of the European Working Group on Sarcopenia in Older People (EWGSOP). Muscle mass was measured with DXA scan; skeletal muscle mass index (SMI) and hand dynamometry were defined with cut-off points obtained for the Chilean population. For a 3m walking speed we used the cut-off point of the EWGSOP definition. Nutritional status and obesity were defined according to World Health Organization standards. Association between sarcopenia and age, gender, BMI and lean/fat mass ratio was estimated by logistic regression models.
Results: The prevalence of sarcopenia was 19.1% (95%CI: 16.8%-21.8%), similar in men and women. There was an increasing trend of sarcopenia by age group and a decreasing trend with nutritional status. After logistic regression, sarcopenia was positively associated with age (OR=1.10; 95%CI:1.06-1.15) and falls (OR=1.83; 95%CI:1.07-3.15) and negatively associated with overweight (OR=0.31; 95%CI:0.16-0.59), obesity (OR=0.02; 95%CI:0.004-0.11), lean mass/fat mass ratio (OR=0.69; 95%CI:0.48-0.9997), knee height (OR=0.78; 95%CI:0.68-0.89) and calf circumference (OR=0.87; 95%CI:0.77-0.97).
Conclusions: The total prevalence of sarcopenia was 19.1% increasing with age reaching 39.6% in people of 80 or more years of age. A negative association of sarcopenia with overweight, obesity and lean/fat mass ratio was observed. Although the high prevalence of obesity (35.9%), only 2% of obese people were sarcopenic.
Keywords: Sarcopenia; community-dwelling older people; muscle mass; muscle strength.