association of 25 (oh)-d3 level with the cyp27b1 rs10877012 variants and metabolic parameters in t2dm patients from kurdistan, iraq

Background:there is an increasing prevalence of type 2 diabetes mellitus (t2dm) worldwide. the deficiency of vitamin d is a worldwide health problem that can increase susceptibility to t2dm. cytochrome p450 family 27 subfamily b member 1 (cyp27b1) encodes the enzyme 1α-hydroxylase in the kidney, which converts 25 (oh)-d3 to 1,25 (oh)2-d3. the cyp27b1 rs10877012 g/t polymorphism is located in the gene promoter and can influence vitamin d3 level. objectives: this study aimed to investigate the relationship between cyp27b1 gene polymorphism and the 25 (oh)-d3 serum level and the risk of t2dm. additionally, the effect of 25 (oh)-d3 level on metabolic parameters was investigated. methods: we investigated 310 individuals including 205 t2dm patients and 105 healthy subjects from the city of al-sulaymaniyah, kurdistan of iraq. the cyp27b1 gene variants were identified by the polymerase chain reaction followed by digestion with hinfi restriction enzyme. results: the mean level of 25 (oh)-d3 was 18.4±8.5 ng/ml in t2dm patients and 24.1±9.3 ng/ml in healthy controls (p<0.001). significantly higher body mass index (bmi), hba1c level, and fasting blood sugar concentration were detected in individuals with vitamin d insufficiency (p=0.009, p=0.001, and p=0.01, respectively) and vitamin d deficiency (p=0.025, p<0.001, and p<0.001, respectively) compared to those with a sufficient level of vitamin d. the t allele frequency of cyp27b1 was 38.1% in controls and 40.2% in patients (p=0.6). in the presence of the gt genotype, a significantly lower level of 25 (oh)-d3 was obtained compared to the gg genotype (p=0.02) among the patients. conclusion: we found that the cyp27b1 rs10877012 polymorphism was not a risk factor for t2dm but it affected the level of 25 (oh)-d3 in diabetic patients and vitamin d deficiency and insufficiency increased the values of bmi, hba1c, and fbs as the metabolic parameters involved in the development of t2dm.