Vitamin D deficiency is associated with sarcopenia in older Koreans, regardless of obesity: the Fourth Korea National Health and Nutrition Examination Surveys (KNHANES IV) 2009.

BACKGROUND: An association between vitamin D status and sarcopenia has not been shown in a community-dwelling cohort, despite the well-documented relationship between vitamin D status and falls.

OBJECTIVE: Our objective was to investigate whether vitamin D level is associated with sarcopenia in older Koreans.

DESIGN AND SETTING: The Fourth Korea National Health and Nutrition Examination Survey in the Korean population was conducted in 2009.

PARTICIPANTS: Participants included 1380 men and 1789 women aged 50 yr or older.

MEASUREMENTS: Serum 25-hydroxyvitamin D [25(OH)D] and PTH levels were measured. Sarcopenia was defined as an appendicular skeletal muscle mass divided by body weight that was less than 2 sd below the sex-specific mean for young adults. Obesity was defined as a body mass index (BMI) of 27.5 kg/m(2) or higher.

RESULTS: 25(OH)D level correlated negatively with appendicular fat mass and positively with appendicular skeletal mass. The groups with sarcopenic obesity and sarcopenia only had lower 25(OH)D levels than did the nonsarcopenia groups. However, 25(OH)D levels did not differ between the sarcopenic obesity and sarcopenia groups. After adjustment for age, sex, BMI, and lifestyle factors, compared with those in the lowest quartile of 25(OH)D level, participants in the highest quartile had an odds ratio for sarcopenia of 0.47 (95% confidence interval = 0.30-0.73; P for trend = 0.001). There was no association between PTH and sarcopenia after adjustment of BMI.

CONCLUSIONS: Vitamin D levels were significantly lower in subjects with sarcopenia than in those without, regardless of obesity. We found a strong inverse association between 25(OH)D level and sarcopenia in the older Korean population.