Abstract: Abstract: Objective To explore the correlation between body mass index (BMI), parathyroid hormone (PTH) and 25- hydroxyvitamin D [25(OH)D] in patients with type 2 diabetes mellitus (T2DM). Methods A total of 110 patients with T2DM were selected in Beijing Chaoyang Hospital. According to the BMI level, patients were divided into normal weight group (BMI 18.5-23.9 kg/m2, n=24), overweight group (BMI 24.0-27.9 kg/m2, n=47) and obesity group (BMI≥28.0 kg/m2, n=39). Data of age, gender, smoking history, BMI, abdominal circumference and hip circumference were recorded in three groups of patients. Fasting peripheral blood samples were collected in early morning, and serum levels of total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglyceride (TG), serum albumin (ALB), urea nitrogen (BUN), serum creatinine (Cr), serum calcium (Ca2+ ), serum phosphorus (P), free fatty acids (FFA), fasting blood glucose (FPG) and fasting insulin (FINS) were detected by automatic biochemical analyzer. The glycosylated hemoglobin (HbA1c) was detected by high performance liquid chromatography. The high sensitivity C-reactive protein (hs CRP) was detected by latex enhanced immunoturbidimetric method. The PTH and 25(OH)D were detected by immunochemical method. The homeostasis model assessment-insulin resistance (HOMA-IR) index was calculated. The estimated glomerular filtration rate (eGFR) was calculated according to the modification of diet in renal disease (MDRD) formula. The levels of PTH, 25(OH)D and other indicators were compared between three groups. The correlation of BMI and other indicators were analyzed by multiple linear stepwise regression. Results The abdominal circumference, hip circumference and FINS were significantly higher in overweight group than those in normal weight group (P＜0.05). The abdominal circumference, hip circumference, PTH, FINS and HOMA-IR were significantly higher in obesity group than those in normal weight group (P＜0.05). Compared with overweight group, abdominal circumference, hip circumference, hs CRP and PTH were significantly higher in obesity group (P＜0.05). Multiple linear stepwise regression analysis showed that BMI was positively correlated with hip circumference (β=0.293), abdominal circumference (β=0.060), FINS (β=0.026) and PTH (β=0.019). Conclusion There is a significant association between higher BMI and PTH in patients with T2DM, but the relationship with 25(OH)D remains to be further studied.

Key words: diabetes mellitus, type 2, body mass index, arathyroid hormone, 25-hydroxyvitamin D