IgM levels were positively correlated with obesity (ρb = 0.156, P = 0.020), dyslipemia (ρb = 0.140, P = 0.029), COPD (ρb = 0.133, P = 0.037) and cancer (ρb = 0.173, P = 0.007). This evidence concerns the gene CD40LG and obesity due to melanocortin 4 receptor deficiency.