Vitamin D supplementation may be an effective strategy to slow or reverse the progression from prediabetes to diabetes, according to results of a meta-anlysis published in the Journal of the Endocrine Society.
“Vitamin D deficiency and type 2 diabetes are escalating health problems worldwide,” Naghmeh Mirhosseini, MD, PhD, of the Pure North S’Energy Foundation in Canada, and colleagues wrote. “The results presented here provide promising evidence that vitamin D supplementation improves glycemic control and attenuates insulin resistance in prediabetics or individuals at high risk of developing diabetes.”
To systematically review the effect that vitamin D supplementation has on glycemic control and insulin resistance, Mirhosseini and colleagues searched databases for studies published from 1999 to April 2017 and conducted a meta-analysis of placebo-controlled clinical trials examining glycemic outcome measures among adults at risk for type 2 diabetes (defined as having prediabetes, overweight or obesity).
Researchers identified 28 studies to evaluate (11 focused on adults with prediabetes and 16 on populations at high risk for diabetes; mean age of participants, 26-71 years; n = 3,848).
Across all studies, researchers determined that vitamin D supplementation reduced HbA1c by –0.48% vs. control groups (95% CI, –0.79 to –0.18; P = .002). In addition, fasting plasma glucose was reduced by –0.46 mmol/L (95% CI, –0.74 to –0.19; P = .001) and homeostasis model assessment of insulin resistance decreased by –0.39 (95% CI, –0.68 to –0.11; P = .007).
Although there was no statistically significant difference in the change of HbA1c or HOMA-IR when vitamin D was combined with calcium supplementation, FPG and 2-hour postload plasma glucose showed greater reduction through this combination.
Researchers also found that vitamin D supplementation more effectively decreased HbA1c (P = .05) and FPG (P = .05) when serum 25-(OH)D concentration was at least 86 nmol/L.
“If left untreated, prediabetic individuals are at increased risk with approximately half expected to go on to develop type 2 diabetes,” the researchers wrote. “Based on these findings, vitamin D supplementation appears to offer a safe and affordable modification to slow or reverse the progression of prediabetes.” – by Melissa J. Webb
Disclosures: The authors report no relevant financial disclosures.