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Association of Vitamin D Deficiency and Poor Glycemic Control in Patients With Type 2 Diabetes Mellitus

Year: 2026

Type: article

Abstract: BACKGROUND: Vitamin D deficiency is common among patients with type 2 diabetes mellitus and may be associated with inadequate glycemic control. OBJECTIVE: To determine the association between vitamin D deficiency and poor glycemic control among adults with type 2 diabetes mellitus. MATERIALS AND METHODS: This cross-sectional study was conducted at Lady Reading Hospital (LRH), Peshawar, Pakistan, from March 2024 to February 2025 among 350 adults with type 2 diabetes mellitus. Serum 25-hydroxyvitamin D (25(OH)D) and glycated hemoglobin (HbA1c) measurements were obtained from hospital laboratory records. Serum 25(OH)D was measured using an enzyme-linked immunosorbent assay (ELISA), according to the laboratory standard operating procedure. Vitamin D deficiency was defined as a serum 25(OH)D level <20 ng/mL and poor glycemic control was defined as HbA1c ≥7.0%. Data were analyzed using descriptive statistics, the chi-square test, independent-samples t-test, and binary logistic regression. Multivariable binary logistic regression was performed to assess the independent association between vitamin D deficiency and poor glycemic control after adjustment for age, BMI, diabetes duration, hypertension, dyslipidemia, physical inactivity, dietary adherence, medication adherence, previous diabetes education, and smoking. Adjusted odds ratios (AORs) with 95% confidence intervals (CIs) were reported. RESULTS: Among 350 participants, 218 (62.29%) were vitamin D deficient and 132 (37.71%) were non-deficient. Poor glycemic control was present in 226 (64.57%) participants, while 124 (35.43%) had adequate control. Vitamin D deficiency was observed in 164 (72.57%) participants with poor glycemic control compared with 54 (43.55%) with adequate control (p <0.001). Participants with poor glycemic control had lower mean serum 25(OH)D levels than those with adequate control (16.72 ± 6.43 vs. 23.84 ± 7.16 ng/mL; p <0.001). After adjustment for the prespecified covariates listed above, vitamin D deficiency was associated with higher odds of poor glycemic control (AOR = 2.87, 95% CI: 1.76-4.68; p <0.001). CONCLUSION: Vitamin D deficiency was common and was independently associated with higher odds of poor glycemic control among adults with type 2 diabetes mellitus. Given the cross-sectional design, this association should not be interpreted as causal, and prospective studies are needed to clarify the relationship.

Source: Cureus

DOI: 10.7759/cureus.117342