A total of 1,390 subjects from the prospective Vlagtwedde-Vlaardingen cohort were genotyped for two single nucleotide polymorphisms (SNPs) in SOD2 and four SNPs in SOD3, which were further analysed for associations with the presence of bronchial hyperresponsiveness (BHR; provocative concentration causing a 10% fall in the forced expiratory volume in one second (FEV(1); PC(10) <or=8 mg mL(-1) of histamine), COPD (defined as Global Initiative for Chronic Obstructive Lung Disease stage II or higher), lung function level and the longitudinal course of FEV(1).