Age and male/ female ratio were not associated with the difference of leptin status between asthma and non-asthma controls (coefficient:−0.031, 95% CI: −0.123–0.061, p = 0.495; coefficient:0.172, 95% CI: −2.445–2.789, p = 0.895), as well as between severe and mild asthma cases among overall populations (coefficient:−0.072, 95% CI: −0.208–0.063, p = 0.279; coefficient: 2.373, 95% CI: −0.414–5.161, p = 0.090). This evidence concerns the gene LEP and asthma.