The evaluation of the vitamin D level i̇n i̇mpai̇red fasting glucose and i̇mpai̇red glucose tolerance (prediabeti̇c) pati̇ents

Introduction and Aim: Impaired fasting glucose tolerance is defined for the people whose fasting blood glucose level is consistently elevated above what is considered normal levels, however, it is not high enough to be diagnosed as diabetes mellitus. Impaired glucose tolerance is defined the people whose second hour plasma glucose level is higher than normal but not high enough to diagnose diabetes mellitus. Vitamin D deficiency causes rickets in children and osteomalacia in adults related with increased bone turnover, reduced bone density, increasing rate of fractures, increasing muscle weakness and myopathy. Low serum 25-hydroxyvitamin D level cause glucose intolerance, diabetes mellitus and metabolic syndrome. There are conflicting data in the literature showing the relationship between vitamin D levels and prediabetes. Our aims in this study are to evaluate 1) serum 25-hydroxyvitamin D levels in prediabetic patients and 2) vitamin D deficiency or insufficiency is the factor for developing prediabetes or not. Material and Method: The study population consisted of 220 patients that consisted of 85 patients who diagnosed with isolated IFG, 50 patients who diagnosed with isolated IGT, 85 patients who diagnosed with both IFG and IGT and 80 normoglysemic healty subjects whose ages, genders and body mass index (BMİ) (kg/m2) were compatible. A detailed history and physical examination of the patients were performed. Height, weight, age, waist circumference and body mass index were calculated and recorded. 25-hydroxy vitamin D, calcium, phosphorus, albumin and parathyroid hormone (PTH) levels were studied from blood samples collected from cases. According to the previosly published criterian, 25 hidroxyvitamin D levels were categorized as adequate vitamin D levels as >30 ng/ml, insuffiency of vitamin D as 20-30 ng/ml and defiency of vitamin D as <20 ng/ml. Findings: This study showed a statistically significant difference of 25 hidroxyvitamin D levels between the control group (16.63±9.78 ng/ml) and İGT (11.69±6.48 ng/ml), (p<0.007), IFG+IGT group (13.22±7.24 ng/ml), (p<0.047). No differences were shown between the control groups and IFG groups 25 hidroxyvitamin D levels. No differences were shown between IFG group, IGT group and IFG+IGT group 25 hidroxyvitamin D levels. Conclusion: İt is considered that the vitamin D insufficiency and deficiency increase the risk of developing impaired fasting glucose, impaired glucose tolerance, impaired fasting glucose and impaired glucose tolerance combined. However, this risk was found to be statistically significant of vitamin D deficiency only in the development of impaired glucose tolerance (OR 2.57, %95 GA, 1.01-6.53, p=0.043). Keywords: Impaired fasting glucose, impaired glucose tolerance, prediabet, vitamin D, vitamin D deficiency.