Front Nutr. 2026 May 19;13:1811665. doi: 10.3389/fnut.2026.1811665. eCollection 2026.
ABSTRACT
OBJECTIVE: This study aimed to explore the dose-response associations of serum vitamin D levels with metabolic parameters and microalbuminuria (ACR) in diabetic patients, to identify the critical clinical threshold of vitamin D for renal and metabolic benefits, and to clarify the population heterogeneity of these associations stratified by microalbuminuria status.
METHODS: A total of 485 diabetic patients were retrospectively enrolled and divided into four groups according to vitamin D quartiles: Q1 (≤32.37 nmol/L, n = 121), Q2 (32.38-45.70 nmol/L, n = 121), Q3 (45.71-59.98 nmol/L, n = 122), and Q4 (≥59.99 nmol/L, n = 121). Spearman’s correlation analysis, multivariate linear regression analysis, and restricted cubic spline (RCS) modeling were used for statistical analyses, with a stratified analysis performed by microalbuminuria status.
RESULTS: The median serum vitamin D level was 45.7 nmol/L in this cohort, with a vitamin D deficiency/insufficiency rate of 75.1%. Serum vitamin D levels were significantly inversely correlated with HbA1c (ρ = -0.425), fasting glucose (ρ = -0.386), triglycerides (ρ = -0.358), BMI (ρ = -0.302), and ACR (ρ = -0.286) (all p < 0.001). Compared with Q4, Q1 patients had a 1.95% higher HbA1c (95% CI: 1.52-2.38) and a 68.95 mg/g higher ACR (95% CI: 50.12-87.78). RCS analysis revealed a linear dose-response relationship between vitamin D (20-50 nmol/L) and reductions in HbA1c (0.32% per 10 nmol/L) and ACR (12.75 mg/g per 10 nmol/L), with a plateau effect observed above 50 nmol/L. The inverse association between vitamin D and ACR was significantly stronger in patients with microalbuminuria (β = 75.68 vs. 43.52, interaction p < 0.001).
CONCLUSION: Vitamin D levels are negatively associated with metabolic abnormalities and microalbuminuria in a dose-dependent manner, suggesting that patients with microalbuminuria may have a stronger association, warranting further investigation in prospective studies.
PMID:42239714 | PMC:PMC13229412 | DOI:10.3389/fnut.2026.1811665
