Figure 2⇓, on page 13 was incorrectly provided. The correct figure is reproduced below, together with its legend.
Effects of physical exercise on lung function in never-smoking and daily-smoking adolescents, aged 13–18 yrs, attending both questionnaire and spirometry in the Young-Hunt study. a, c) Males, never-smokers (exercise: ≤1 day·week−1, n=349; 2–3 days·week−1, n=593; ≥4 days·week−1, n=570); b, d) females, never-smokers (exercise: ≤1 day·week−1, n=445; 2–3 days·week−1, n=671; ≥4 days·week−1, n=344); e, g) males, daily smokers (exercise: ≤1 day·week−1, n=171; 2–3 days·week−1, n=99; ≥4 days·week−1, n=47); f, h) females, daily smokers (exercise: ≤1 day·week−1, n=219; 2–3 days·week−1, n=96; ≥4 days·week−1, n=39). Students who reported ever having asthma were excluded. Per cent differences and 95% confidence intervals for differences were calculated on a logarithmic scale using those who had the lowest level of exercise (≤1 day·week−1) as a reference, and adjusting for age, height, weight, passive smoking at home, rhinitis and acute bronchitis with cough. FVC: forced vital capacity; FEV1: forced expiratory volume in one second.
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