The aim of this study was to evaluate whether low vitamine D levels were associated with skeletal muscle dysfunction in COPD
This cross sectional analysis included 1092 COPD participants with FEV1/FVC < 70% (aged >40 years) in Korea National Health and Nutrition Examination Surveys, which were conducted from 2008 to 2011. Body composition were measured by dual-energy x-ray absorptiometry (DXA). Serum 25-hydroxyvitamine D (25(OH)D), parathyroid hormone (PTH) levels were measured. For the criteria for sarcopenia, the recommended criteria of the European Working Group on Sarcopenia in Older People (EWGSOP) and of the Asia Working Group for Sarcopenia (AWGS) were used. We divided subjects to thee group according to 25 (OH)D level. (Deficiency ≤20 ng/ml, insufficiency 21-29 ng/mL, Sufficiency ≥ 30 ng/ml)
Vitamine D levels were positive correlated with fat free mass index (FFMI), skeletal muscle mass index (SMI), appendicular skeletal muscle mass index (ASMI) in COPD. (P= 0.010, 0.008, 0.016) However, PTH showed correlation with ASMI only. (P= 0.012) In logistic regression, vitamine D level revealed association with FFMI, SMI, ASMI, which showed lowest P value in ASMI. (P= 0.002, 0.001, <0.001) When classified according to vitamine D level, in deficiency group, prevalence of sarcopenia was higher with trend according to the vitamine D levels. (P <0.001) Using multivariant logistic regression analyses, in deficiency group, the sarcopenia risk increased in which the criteria recommended in EWGSOP and AWGS with the ASMI. (OR 2.519 , P= 0.003; OR 2.066 P= 0.014)
Our finding suggest that low vitamine D level is associated to decrease of skeletal muscle mass, particularly in limb muscle dysfunction, which may be a risk factor of sarcopenia in COPD.