Lung Function of Preterm Children by COPD PRSPolygenic risk score (PRS) for FEV1 and FVC was calculated in children born prematurely. COPD risk score was strongly associated with FEV1 (-0.05 z score/decile, P=6.5 × 10-9) and FEV1/FVC (-0.07 z score/decile, P=4.4 × 10-11) but not FVC. Children at highest risk had lower lung function by these measures and higher rates of obstructive bronchitis.