A large prospective cohort of 200,000 men suggested thathigher free T and circulating IGF-1 are associated with an elevated risk of prostatecancer, whereas higher SHBG was associated with a lower risk (hazard ratio of 0.95per 10 nmol/L of increment) (30).There are possible, nevertheless, confounding factors, since lower SHBG and higherIGF-1 levels are found in the presence of obesity (4,31), and it has been suggested that men with obesity are at increasedrisk of prostate cancer progression and high-grade forms of the tumor (32). Here, IGF1 is linked to obesity due to melanocortin 4 receptor deficiency.