LEP and asthma: In 6- to 11-year-olds with asthma, a study found that obesity markedly amplifies oxidative stress: serum leptin, as well as MDA, and 8-isoprostane in exhaled-breath condensate, were all significantly higher in the obese-asthma group than in non-obese asthmatics and healthy controls, and each of these markers rose in proportion to body mass index (BMI) (MDA r = 0.48; 8-isoprostane r = 0.47).