ABSTRACT

Vitamin D is thought to have a probable helpful effect on the action of insulin. There is little information regarding this relationship in prediabetic elderly subjects in the literature. The aim of this study was to investigate differences in insulin sensitivity and metabolic parameters according to vitamin D levels in prediabetic elderly subjects. Seventy nine elderly subjects (31 male, 48 female; mean age: 75.8±6.04 years) who admitted to the Department of Geriatry of Gulhane Military Medical Faculty were included in the study. According to plasma concentrations of 25(OH)D, the subjects were categorized in 2 groups: those with a level lower than 20 ng/mL (vitamin D deficiency: Group I) and those with a level higher than 20 ng/mL (vitamin D insufficiency [20-30 ng/mL] or vitamin D normal [>30 ng/mL]; Grup II). Serum insulin and HOMA-IR levels in Group I were significantly higher than those in Group II (p=0.025 and p=0.021, respectively). In all the subjects there was a statistically significant negative correlation between plasma 25(OH)D levels and HOMA-IR and insulin levels (r=-0.287 and r=-0.302, respectively). Our results indicate that insulin sensitivity may decrease in prediabetic elderly subjects with vitamin D deficiency. Further randomized, controlled, and prospective studies are necessary to investigate the relationship between vitamin D and these parameters in prediabetic elderly subjects.

Keywords: Insülin sensitivity, prediabetes, vitamin D, elderly