Serum periostin levels were significantly elevated in both asthma groups compared with healthy controls [moderate: 51.1 (48.8–52.8) pg/mL; severe: 52.5 (48.6–56.4) pg/mL vs. controls: 35.5 (25.1–40.8) pg/mL; p < 0.001]. This evidence concerns the gene POSTN and asthma.