In 1 study, birth by cesarean delivery was associated with higher BMI, total cholesterol, low-density lipoprotein cholesterol, and leptin levels at age 20 years,23 but other studies have not identified associations between cesarean delivery and markers of metabolic risk.24 To further investigate the long-term association of birth by cesarean delivery with obesity and metabolic risk, we evaluated the association of cesarean delivery with obesity and incidence of type 2 diabetes in an ongoing prospective cohort study followed up for nearly 3 decades. This evidence concerns the gene LEP and Obesity.