Endocrine Abstracts

Introduction: Vitamin D has a potentially beneficial role in insulin resistance, but there is a lack of evidence in elderly. We report preliminary results of an ongoing study that investigated the effect vitamin D replacement treatment (12 weeks) on insulin resistance and metabolic parameters in elderly people with normal glucose tolerance.

Methods/design: The study’s eligibility criteria were body mass index <30.0 kg/m², creatinine levels <1.2 mg/dl, no evidence of prediabetes and diabetes, no self-reported use of hypoglycemic drugs, and fasting serum glucose <100 mg/dl. Eighty-six participants (aged≥65 years) were eligible for the present investigation. Serum concentrations of 25(OH) D were categorized as deficient (group I, <20 ng/ml), insufficient (group II, 20 to 30 ng/ml), or normal (group III, >30 ng/ml) vitamin status, respectively. Group I was treated initially with 300 000 international units (IU) of vitamin D₃ ampoule orally once for six weeks, and then 880 IU of vitamin D₃ plus 1000 mg of ionized calcium tablet daily thereafter. Group II was treated with 880 IU of vitamin D₃ plus 1000 mg of ionized calcium tablet daily. Group III received with 400 IU of vitamin D₃ plus 600 mg of ionized calcium tablet as daily supplement.

Results: There were no significant differences in all baseline parameters except vitamin D levels among three groups. After 12 weeks of vitamin D replacement therapy, 95.3% of all subjects had 25(OH) D levels within the normal range with a mean level of 53.4±21.3 ng/ml. There was a significant reduction in HOMA-IR scores in group I (P<0.001), but not in group II (P=0.074) and group III (P=0.123). There were no statistically significant differences in lipid parameters in all groups.

Conclusion: We found that supplementation in vitamin D deficient subjects may modify insulin sensitivity in elderly.