Severe asthma cases showed markedly high leptin level than that in mild asthma cases among overall populations (SMD: 1.638, 95% CI: 0.952–2.323, p < 10−4) and Asians (SMD: 2.600, 95% CI: 1.854–3.345, p < 10−4) (Table 2, Fig. 4). The gene discussed is LEP; the disease is asthma.