Vitamin D as changeable risk factor in relation with overweight and obesity

New researches suggest the importance of vitamin D in relation to different diseases; moreover concentration of vitamin D is considered to be a possible nutritional factor that can influence onset of type 2 diabetes. The aim of this work is to investigate the correlation between diabetic risk factors and levels of vitamin D in overweight and obese patients. This study includes 104 patients with an age between 16 and 75 and with a Body Mass Index (BMI)>25 selected by a program of nutritional education in Medicina del Lavoro in Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano. For these studies, dietary information, anthropometric measurements, impedance evaluation and blood tests were recorded. The data were analyzed using linear regression for correlating different parameters and statistical analysis was performed using GraphPad and ttest. Concerning vitamin D levels is estimated that only 13.5% of patients had optimal values, between the remaining 86.5% of patients that have sub-optimal values, 14.4% had levels of deficiency (less than 10 ng/ml). First of all we tested a statistical correlation between BMI, % of fat mass and circulating levels of vitamin D, demonstrating that there is a significant negative correlation between these factors. To support the hypothesis of an association between vitamin D and type 2 diabetes, we studied specific risk factors for diabetes, in particular we examined the relationship of homeostasis model assessment index (HOMA) and concentration of triglycerides and HDL cholesterol (TG/HDL), dividing patients in 4 groups according to BMI. Using linear regression there was a statistically significant correlation of vitamin D with HOMA and with ratio TG/HDL. In fact, within the group of patients in the study, as BMI values increase there is a progressive decrease in vitamin D plasma levels and a concomitant increase in HOMA index values or in ratio TG/HDL. Finally, to estimate the daily intake of vitamin D we used questionnaires created by “Osservatorio Grana Padano”. The intake of vitamin D (4.5 g/day) is much lower than the recommended dose, so not enough to ensure adequate vitamin D requirements. The present study suggests a significant effect of vitamin D on several players involved in the pathogenesis of diabetes making vitamin D a potential target to interfere with this important and growing health problem. For these reasons an useful approach to reduce the risk of developing such disease could be a change in lifestyle such as a correct vitamin D intake in addition to weight contro