Background/Purpose: Sarcopenia is a syndrome characterized by progressive loss of skeletal muscle mass, which results in decreased muscle strength and impairment of functional capacity. Moreover, sarcopenia is an important clinical problem in older people with some adverse outcomes including an increased risk of death. Despite the increasing frequency of this clinical condition, prospective data about risk factors for low muscle mass are scarce and few studies have performed a comprehensive evaluation of clinical data, laboratory bone parameters and bone mineral density (BMD) to determine more accurately the contribution of each of these variables to risk of low muscle mass in elderly persons. Moreover, the influence of the visceral fat assessed by DXA on low muscle mass is poorly studied. Thus, this study aimed to identify the main risk factors (clinical, laboratory parameters, BMD, body composition by DXA including visceral fat) for low muscle mass, in a longitudinal, prospective, population-based cohort of Brazilian older women.

Methods: A total of 408 women aged 65 years and older from the São Paulo Ageing & Health study (SPAH) was evaluated with clinical data, laboratory bone tests, BMD and body composition by DXA. All risk factors were performed at baseline (2005-2007). Along with the Foundation for the National Institutes of Health (FNIH) criteria, low muscle mass was defined when appendicular lean mass divided by body mass index (ALM/BMI) is less than 0.512 (value for female). After a mean follow-up of 4.3±0.8 years, subjects were classified according to the appendicular muscle mass obtained by DXA. Logistic regression models were used to identify independent risk factors for low muscle mass.

Results: 116 women (28.4%; 95% CI: 24.0-32.7) had low muscle mass at the end of follow-up. Age averages were 73.3±4.9 years and 72.5±4.5 years, in the low muscle mass group and in the normal muscle mass group, respectively (p=0.11). Mean BMI was 30.6±5.2 kg/m² in low muscle mass group and 28.1±4.7 kg/m² in normal group (p<0.001). In multivariate analyses, predictors of low muscle mass were: number of falls (OR = 1.14, 95% CI 1.02-1.27, p = 0.016), TSH levels (OR = 1.08, 95% CI 1.01-1.15, p = 0.018, per each 1 μUI/L-increase), serum creatinine (OR = 11.11, 95% CI 2.78-33.33, p < 0.001, per each 1 mg/dL-decrease) and visceral adipose tissue (VAT) mass (OR = 1.17, 95% CI 1.07-1.27, p < 0.001, per each 100g-increase).

Conclusion:

Falls, higher TSH, lower creatinine and higher VAT were risk factors for low muscle mass in community-dwelling older women. These results reinforced that visceral fat, which is associated with metabolic syndrome and chronic inflammation, is related to muscle mass consumption and fragility in elderly. Taken together, these findings support the notion that more attention should be paid to these factors in clinical practice, since they are potentially reversible with adequate therapeutic intervention.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/risk-factors-for-low-muscle-mass-in-community-dwelling-older-women-a-population-based-prospective-cohort-study-in-brazil-the-sao-paulo-ageing-health-study/