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 control