Endocrine Abstracts

We investigated the SNP rs16944 in German type 2 diabetes (T2D) patients and healthy controls (HC) and correlated the findings with concentrations of VD metabolites.

Methods: 504 T2D patients and 447 HC were genotyped by a Taqman assay. Additionally 25(OH)D₃ and 1,25(OH)₂D₃ plasma levels of 76 T2D patients and 267 HC were measured by radioimmunoassay.

Results: The AA genotype was significantly less frequent in T2D compared to HC whereas GG and AG genotypes were more frequent in T2D (AA: 48.5 vs 37.95%; AG 40vs 49.7%; GG: 11.4 vs 12.4%; P=0.003). Furthermore the allele A was less (68.6 vs 62.7% OR=0.77; 95% CI: 0.64–0.93) and allele G was more frequent (31.4 vs 37.3% OR=1.3 95% CI: 1.07–1.57, P=0.008) in T2D patients compared to HC. Both T2D patients and HC with IL1β genotypes AA and AG did not differ for the VD metabolites. However T2D patients with the GG genotype showed significantly lower levels of 25(OH)D₃ (median 34.95 vs 13.7 ng/ml P=9×10⁻⁶) and 1,25(OH)₂D₃ (median 59.05 vs 41.15 pg/ml P=0.006) compared to HC with the same genotype.

Conclusion: We describe an association of the IL1β with T2D in German patients. Significantly lower 25(OH)D₃ and 1,25(OH)₂D₃ levels were observed in T2D patients with the GG genotype. Whereas the major allele A appears to be protective, the minor allele G is may predispose to T2D in combination with a vitamin D deficiency. Our results suggest that VD deficiency enhances the genetic risk for T2D conferred by the genotype GG of IL1β SNP rs16944. Whether and how vitamin D interacts with IL1β through this polymorphism is subject to further studies.