Do childhood respiratory infections continue to influence adult respiratory morbidity?

¹ The University of Melbourne, Australia
² Imperial College, London, UK
³ GSF Institute of Epidemiolgy, Neuherberg, Germany
⁴ Hospital du Haut-Lévêque, France
⁵ Uppsala University, Sweden
⁶ Municipal Institute of Medical Research Barcelona, Spain
⁷ The University of Bergen, Norway

^* To whom correspondence should be addressed. E-mail: s.dharmage{at}unimelb.edu.au.

	Abstract

To examine the influence of childhood respiratory infections on adult respiratory health. In 1992–94, European Community Respiratory Health Survey recruited community based samples of 20–44 year old people from 48 centers in 22 countries. Study participants completed questionnaires and underwent lung function testing. On average, 8.9 years later, 28 centres re-investigated their samples using similar methods. Mixed effects models comprising an estimate for the random variation between centres were used to evaluate the relevant associations. 9,175 participated in both studies, of which 10.9% reported serious respiratory infections before 5 years (SRI) and 2.8% reported hospitalisation for lung disease before 2 years (HDL). SRI was associated with current wheeze (OR=1.9; 95% CI=1.7–2.2), asthma (OR=2.5 95% CI 2.2–3.1), and lower FEV₁ (89ml 95% CI 54–126), lower FVC (49ml 95% CI 8–90), and FEV₁/FVC ratio (-1.2% 95% CI -1.8 to -0.6 ). Childhood respiratory infections were also associated with new asthma (OR 1.5 95% CI 1.03–2.0]), new wheeze (OR=1.5 95% CI 1.0–2.4), and persistent wheeze (OR 2.2 95% CI 1.4–3.6) but not with decline in lung function. Similar findings were observed for HDL. These associations were consistent across centers (p _{heterogeneity} >0.05). SRI was associated with lower FEV₁ when excluding ever asthmatics and current wheezers. The impact of early infections was larger in subjects exposed to maternal (p _interaction=0.09) or active (p _interaction=0.02) smoking. The impact of childhood respiratory infections on respiratory system may not only last into adulthood but also influence development and persistence of adult respiratory morbidity. (Word count 230)