LEP and obesity due to melanocortin 4 receptor deficiency: The results of this meta-analysis were largely limited by not only the lack of a consensus to measure serum leptin among studies, but also the different sample sizes used in every work, the different criteria used to classify the severity of asthmatic patients with obesity, as well as the type of control individuals recruited, which included non-obese patients with asthma and/or non-asthmatic subjects with different BMIs.