Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 14 5 2015 10 20 545 551 EN Martín Bedolla-Barajas Allergy and Clinical Immunology Service, Division of Internal Medicine, Hospital Civil de Guadalajara ”Dr. Juan I. Menchaca”, Guadalajara, Jalisco, Mexico. Jaime Morales-Romero Instituto de Salud Pública, Universidad Veracruzana, Xalapa,Veracruz, Mexico. Tonatiuh Ramses-Bedolla-Pulido Universidad Guadalajara Lamar, Guadalajara, Jalisco, Mexico. Lourdes Fabiola-García-Padilla Medical Doctor. Universidad de Guadalajara, Guadalajara, Jalisco, Mexico. Dante Hernández-Colín Head of Research, Hospital Civil de Guadalajara ”Dr. Juan I. Menchaca”, Guadalajara, Jalisco, Mexico. 2015 10 19 2015 10 19 The clinical behavior of asthma varies with age at onset. This study was undertaken to identify associated markers of adult-onset allergic asthma (age ≥20 years).This cross-sectional study compared two groups: 58 patients with asthma onset at <20 years and 66 with onset at ≥20 years. They were compared depending on results of clinical history, and body mass index (BMI), aeroallergen sensitization, total serum IgE, eosinophil count, asthma control test, and asthma severity level.Ages at first asthma episode were 10.0 ± 6.6 and 33.4 ± 10.5 (p <0.001) in the <20 and ≥20 group, respectively. BMI was higher in adult asthmatic subjects (29.8 versus 27.1, P=0.017), but BMI ≥30 kg/m2 was not associated with asthma onset in ≥20 years (odds ratio [OR] = 1.56, 95% confidence interval [CI] 0.759 to 3.211; p= 0.227). After multivariate analysis, allergic rhinitis and IgE ≥150 IU/mL were negatively correlated with asthma onset in ≥20 years old (OR adjusted [ORa] = 0.255, 95% CI 0.078 to 0.837,  P= 0.024, and ORa =0.385, 95% CI 0.175 to 0.849,  p= 0.018, respectively).Adult-onset allergic asthma was not different from early-onset asthma. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/604 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/604/569