Higher vitamin D levels reduce serum FPG, HbA1c, HOMA-IR in diabetic patients
A minimum dose of vitamin D supplementation (100 µg/day or 4,000 IU/day) may already substantially lower serum fasting plasma glucose (FPG), glycosylated haemoglobin (HbA1c) and homeostatic model assessment of insulin resistance (HOMA-IR), a recent study suggests.
In addition, vitamin D supplementation helps control glycaemic response and improves insulin sensitivity in type 2 diabetes patients.
The investigators conducted a systematic review and meta-analysis to determine the effect of vitamin D supplementation and improved vitamin D status on glycaemia and insulin resistance in T2D patients. They searched PubMed/Medline, Cumulative Index to Nursing and Allied Health, and Cochrane Library until January 2017 for prospective clinical trials evaluating the impact of vitamin D supplementation on HbA1c, serum FPG and HOMA-IR in diabetic patients.
Random-effects model was used to synthesize quantitative data. This was followed by a leave-one-out method for sensitivity analysis. The systematic review registration was CRD42017059555. Of the 844 entries identified via literature search, only 24 controlled trials including 1,528 patients with T2D met the inclusion criteria.
Vitamin D supplementation resulted in a significant reduction in HbA1c (mean difference, ‒0.30 percent; 95 percent CI, ‒0.45 to ‒0.15; p<0.001), FPG (mean difference, ‒4.9 mg/dL [‒0.27 mmol/L]; ‒8.1 to ‒1.6 [‒0.45 to ‒0.09 mmol/L; p=0.003) and HOMA-IR (mean difference, ‒0.66; ‒1.06 to ‒0.26; p=0.001). In addition, it also led to a substantial increase in serum 25-hydroxyvitamin D levels (overall increase of 17±2.4 ng/mL [42±6 nmol/L]).
“Type 2 diabetes is a global health concern, with an increased prevalence and high cost of treatment,” according to researchers.