Kaviani M, Abdollahian M, Almasi V, Amini M, Yamini AA.
Endokrynol Pol. 2012;63(3):191-5.
Introduction: Insulin resistance is defined as reduction of insulin-stimulated glucose uptake in skeletal muscles and inadequate suppression of the production of endogenous glucose. The aim of this study was to assess the effect of vitamin D intake on insulin resistance in aged patients.
Materials and methods: This interventional study was carried out on residents of Sadeghieh Nursing Home in Iran. The participants were healthy adults aged ? 65.
For eight weeks, the participants took pills containing 50,000 IU vitamin D(3) per week. Insulin resistance was defined as homeostasis model assessment of insulin resistance (HOMA-IR) ? 2.5. We used McNemar's test, Wilcoxon test, chi-square, and Pearson correlation coefficient and SPSS software (v. 12) to analyse the collected data.
Results: The average age of the 76 participants was 78.7 ± 8 years and 52 of the participants were female. Before and after the study, 37 and four participants had vitamin D deficiency, respectively (p ? 0.001). Impaired fasting plasma glucose (FPG) and insulin resistance was not more prevalent in the participants with vitamin D deficiency. In this study, vitamin D intake had no significant effect on FPG level (p = 0.9), but it increased the prevalence of insulin resistance significantly (p ? 0.001).
Conclusions: In our study, before and after the intervention, vitamin D deficiency had no relationship with FPG level and insulin resistance.
Vitamin D intake had no significant effect on FPG level, but it increased the prevalence of insulin resistance significantly.
We believe that performing more studies, with a longer timespan and larger sample size, as double-blind clinical trials, is necessary.
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- People in the Middle East have very low levels of vitamin D.
- It takes a while to ‘’fill up’’ on vitamin D.
- It takes longer if you are very ‘’empty’’
- It is likely that vitamin D levels did not exceed 20 nanograms until the sometime in the second month.
- Thus there would not have been much time left in the 2 month trial for vitamin D to do any good.
- Start with a loading dose phase
- Have a longer trial - perhaps 4 months.