On the role of vitamin D binding globulin in glucose homeostasis: Results from the San Luis Valley diabetes study
✍ Scribed by Sudha Iyengar; Richard F. Hamman; Julie A. Marshall; Partha P. Majumder; Robert E. Ferrell; D. C. Rao; G. P. Vogler
- Publisher
- John Wiley and Sons
- Year
- 1989
- Tongue
- English
- Weight
- 509 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0741-0395
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✦ Synopsis
Several studies have reported association between noninsulin-dependent diabetes mellitus and GC, the vitamin D binding protein of human plasma, with the GC 1 allele in significant excess among diabetics. Additionally, there is a considerable body of animal data suggesting that vitamin D has a significant impact on insulin secretion. Examination of the insulin levels in Dogrib Indians showed that the lowest levels of fasting insulin were associated with the GC 1 F-1 F genotype. The present study examined levels of glucose, C-peptide, and insulin at fasting and 1 hr and 2 hr following a 75 g oral glucose challenge, in a population of Hispanic-Americans and Anglos in the San Luis Valley of southern Colorado. The sample comprised a total of 468 individuals with normal glucose tolerance. Of these, 289 were Anglos and 179 were Hispanic-Americans. An analysis of covariance was performed to determine the effect of the GC genotypes on mean levels of the primary variables-glucose, C-peptide, and insulin-and a secondary variableinsulinogenic index adjusting for the covariates age, body mass index (BMI), gender, and ethnicity. The analyses revealed that there is a significant difference in mean levels of glucose at fasting (F value = 2.46; P = 0.033) among the GC genotypes in the sample. Additionally, the differences in mean levels of 1 hr postprandial glucose among the GC genotypes although not significant at a 5% level, were significant at the 10% level. No other significant phenotypic effects were observed.