In conclusion , the deficiency of vitamin D is associated with an increased level of BMI in the studies of both diabetic and non-diabetic subjects .
The deficiency of vitamin D is prevalent all over the world .
Studies have shown that vitamin D may play an important role in the development of obesity .
The current study was conducted to quantitatively evaluate the association between serum 25-(OH ) vitamin D levels  and the risk of obesity in both diabetic and non-diabetic subjects .
Multivariate Path Analysis of Serum 25-Hydroxyvitamin D Concentration, Inflammation, and Risk of Type 2 Diabetes Mellitus
Background and Aims . Despite growing interest in the protective role that vitamin D may have in health outcomes , little research has examined the mechanisms underlying this role . This study aim ed to test two hypotheses : ( 1 ) serum 25-hydroxyvitamin D [ 25(OH)D ] is inversely associated with type 2 diabetes mellitus ( T2DM ) and elevated hemoglobin A1c ; ( 2 ) these associations are mediated by serum C-reactive protein ( CRP ) . Methods . Participants aged 20 and older in 2001–2006 National Health and Nutrition Examination Surveys ( n = 8,655 ) with measures of serum 25(OH)D , CRP , hemoglobin A1c , and other important covariates were included in the present study . Logistic regression and path analysis methods were applied to test the study hypotheses . Results . Decreased serum 25(OH)D concentration was significantly associated with increased odds of T2DM .  In males , an estimated 14.9 % of the association between 25(OH)D and hemoglobin A1c was mediated by serum CRP . However , this mediation effect was not observed in females . Conclusion . Using a nationally representative sample , the present study extends previous research and provides new evidence that the effect of  decreased serum vitamin D concentration on T2DM may proceed through increased systemic inflammation in males . Longitudinal studies and r and omized control trials are needed to confirm the present findings
In conclusion , the deficiency of vitamin D is associated with an increased level of BMI in the studies of both diabetic and non-diabetic subjects .
The deficiency of vitamin D is prevalent all over the world .
Studies have shown that vitamin D may play an important role in the development of obesity .
The current study was conducted to quantitatively evaluate the association between serum 25-(OH ) vitamin D levels  and the risk of obesity in both diabetic and non-diabetic subjects .