Evangelia Zaromytidou , Theocharis Koufakis2, Georgios Dimakopoulos3, Despina Drivakou, Stavroula Konstantinidou , Vasiliki Antonopoulou , Maria Grammatiki , Eleni Manthou, Ioannis Iakovou, Anna Gotzamani-Psarrakou, Kalliopi Kotsa 

Background: Data on the efficacy of vitamin D in improving the glycemic status of elderly people with prediabetes are scarce. This open-label, randomized-controlled trial investigated the effect of vitamin D supplementation on glycemic markers of Greek people with prediabetes aged 60 years or above, over 12 months.

Research design and methods: Participants were randomized to a weekly vitamin D3 dose of 25,000 IU (n = 45) or nothing (n = 45), on top of lifestyle measures. Anthropometric and glycemic markers were assessed at baseline, 3, 6, and 12 months.

Results: Supplemented participants demonstrated a significant increase in 25(OH)D concentrations at 3, 6, and 12 months compared to baseline . In the intervention group, fasting glucose was decreased at 6 months compared to baseline (96.12 ± 5.51 vs 103.40 ± 12.05 mg/dl, p < 0.01) and glycated hemoglobin was significantly lower at 6 and 12 months compared to baseline [5.82 ± 0.21% vs 5.87 ± 0.21%, p = 0.004 and 5.80 ± 0.23% vs 5.87 ± 0.21%, p < 0.001, respectively].

Conclusions: Vitamin D could be complementary to lifestyle change strategy for the management of prediabetes in the elderly.