IGF1 and obesity due to melanocortin 4 receptor deficiency: Some of the published studies have shown that serum TC and TG levels are significantly associated with the formation of colorectal polyps [10,25], while other studies have failed to show a similar association or even suggested an inverse association [26].Obesity and high BMI are associated with an increased risk of polyp presence and recurrence after resection, thought to be due to increased levels of insulin resistance and IGF-1 [12,27].