Background: Decreased muscle mass (sarcopenia) and increased fat mass (obesity) with aging may contribute to difficulties with physical fitness, respectively. However, a limited number of studies have examined the association between sarcopenic-obesity and physical fitness.
Purpose: The primary aim of this study was to investigate the prevalence of sarcopenic-obesity from a large cohort of Japanese. We was also examined whether sarcopenic-obesity contribute to decease physical fitness independently level of physical activity.
Methods: This cross-sectional observational study including total 17,530 healthy Japanese men and women 20-80 years of age who recruited between 2004 and 2010. We measured muscle mass and body fat mass using bioelectrical impedance. Physical activity was measured using a pedometer with an accelerometer for 7 days. The physical fitness test was based on the method of the Japan Fitness Test that comprised five items, and total scores of the test were calculated (scores of each item: 1-10). Lowest gender-specific quartile in total score was defined as poor physical fitness. Sarcopenia was defined as skeletal muscle mass index of two SD below the sex-specific mean value for a younger reference group (<40 years) form the entire study population. We defined also obesity based on criteria of the Japan Society for the Study of Obesity.
Results: The prevalence of sarcopenia-obesity was significantly increased with aging (P<0.05). The odds ratio for poor physical fitness was 2.10 (95%CI; 1.74-3.65) and 1.67 (95%CI; 1.26-2.21) for individuals with sarcopenic-obesity, compared with healthy body composition group in men and women, respectively (P<0.05). These trends were similar across level of physical activity.
Conclusion: The results of this cross-sectional observational study suggest that sarcopenic-obesity is associated with poor physical fitness independently physical activity using measured a pedometer with an accelerometer.