In addition, we performed subgroup analysis stratified by age, sex, hypertension, DM, and obesity, to examine the correlation between serum 25(OH)D and the risk of anemia, after adjusting for variables, including PTH, history of osteoporosis, and number of days with arthritis or rheumatism (Supplementary Table 3). The gene discussed is PTH; the disease is obesity due to melanocortin 4 receptor deficiency.