Serum 25-hydroxyvitamin D levels and their association with ketosis in patients with newly diagnosed type 2 diabetes.

This study aimed to investigate the relationship between serum 25-hydroxyvitamin D (25(OH)D) concentrations and ketosis risk in adults with newly diagnosed type 2 diabetes mellitus (T2DM). A total of 1266 newly diagnosed T2DM patients were consecutively enrolled. Participants were categorized into ketosis-prone T2DM (KPDM, n = 243) and non-ketosis-prone T2DM (n = 1023) groups based on urinary ketone status. Serum 25(OH)D levels, metabolic parameters, and the neutrophil-to-lymphocyte ratio were measured. The KPDM group demonstrated significantly lower 25(OH)D levels (median 15.05 vs 17.50 ng/mL, P < .001) and a higher prevalence of vitamin D deficiency (<20 ng/mL: 69.9% vs 61.5%, P = .03). Seasonal variation analysis revealed consistently lower 25(OH)D levels in KPDM patients than in non-ketosis-prone T2DM patients during the summer-autumn months (17.25 vs 20.30 ng/mL, P < .001). Multivariate logistic regression revealed vitamin D deficiency, younger age, an elevated neutrophil-to-lymphocyte ratio, and increased hemoglobin A1c levels as independent predictors of ketosis development. Vitamin D deficiency is independently associated with increased odds of ketosis susceptibility in new-onset T2DM patients.