IGHE and asthma: After adjusting confounding factors, compared with serum IgE level < 100 kU/L in cluster A, higher serum IgE levels (≥ 200 kU/L) in cluster C appeared to show a significantly increased risk of allergic rhinitis [odds ratio (OR), 9.09; 95% confidence interval (CI), 2.20–37.53; P = 0.002] and asthma (OR, 5.94; 95% CI, 1.89–18.69; P = 0.002) at the age of 4 years.