Seemingly, as previously shown in severely obese patients [20], vitamin D and CRP levels were inversely associated, but also this correlation was not maintained after adjustment for BMI, insulin, and insulin resistance, suggesting that the negative association between vitamin D and investigated inflammation parameters (CRP and C3 and C4) is only indirectly mediated by factors associated with obesity. Here, CRP is linked to obesity due to melanocortin 4 receptor deficiency.