LEP and irritable bowel syndrome: In children with IBS, leptin concentrations were positively related to weight SDS (r = 0.56, p < 0.001), BMI SDS (r = 0.63, p < 0.001), waist circumference SDS (r = 0.54, p = 0.001), and WHR (r = 0.33, p = 0.004).