Age and male/female ratio were not associated with the differences of leptin status between asthma and non-asthma controls among overall populations (coefficient: −0.031, 95% CI: −0.123 to 0.061, p = 0.495; coefficient: 0.172, 95% CI: −2.445 to 2.789, p = 0.895) (Table 3). This evidence concerns the gene LEP and asthma.