Characteristics of included studies: case control and cross-sectional studies.

aPlease see Table S2 for detailed assessment.bHigh probability of asthma defined as ≥4 out of the following five items: (1) ≥1 of the following: cough, wheeze, or difficulty breathing; (2) ≥1 of the following: recurrent cough, wheeze, and/or difficulty breathing; atopic history in child; history of asthma in first-degree relative; (3) ≥3 of the following: fast breathing, chest indrawing, prolonged expiration, or rhonchi; (4) good response to bronchodilators; (5) chest X-ray normal or showing hyperinflation.CC, case control; CS, cross-sectional; GA, gestational age; NDI, neurodevelopmental impairment.