Pediatric Pulmonology Respiratory Effects Associated With Wood Fuel Use: A Cross-Sectional Biomarker Study Among Adolescents Erik Van Miert, MSc, Antonia Sardella, MD, Marc Nickmilder, PhD, and Alfred Bernard, PhD* Summary. The use of wood as heating and cooking fuel can result in elevated levels of indoor air pollution, but to what extent this is related to respiratory diseases and allergies is still incon- clusive. Here, we report a cross-sectional study among 744 school adolescents (median age 15 years) using as main outcomes respiratory symptoms and diseases, exhaled nitric oxide, total and aeroallergen-specific IgE in serum, and two epithelial biomarkers in nasal lavage fluid (NALF) or serum, that is, Clara cell protein (CC16) and surfactant-associated protein D (SPD). Information about the wood fuel use and potential confounders was collected via a personal interview of the adolescent and a questionnaire filled out by the parents. Two approaches were used to limit the possible influence of confounders, that is, multivariate analysis using the com- plete study population or pairwise analysis of matched sub-populations obtained using an auto- mated procedure. Wood fuel use was associated with a decrease of CC16 and an increase of SPD in serum, which resulted in a decreased serum CC16/SPD ratio (median 9%, P ¼ 0.001). No consistent differences were observed for the biomarkers measured in exhaled breath or NALF. Wood fuel use was also associated with increased odds for asthma [odds ratio (OR) 2.2, 95% CI: 1.1–4.4, P ¼ 0.02], hay fever (OR ¼ 2.4, 95% CI: 1.4–4.3, P ¼ 0.002), and sensitization against pollen allergens (OR ¼ 2.1, 95% CI: 1.3–3.4, P ¼ 0.002). The risks of respiratory tract infections, self-reported symptoms, and sensitization against house-dust mite were not increased by wood fuel use. The increased risks of asthma, hay fever and aeroaller- gen sensitization, and the changes of lung-specific biomarkers consistently pointed towards respiratory effects associated with the use of wood fuel. Pediatr Pulmonol. ß 2011 Wiley-Liss, Inc. Key words: indoor pollution; lung biomarkers; respiratory disease; sensitization; wood fuel use; wood smoke. Funding source: none reported. INTRODUCTION Evidence is increasing that indoor pollution plays an important role in the development of respiratory dis- eases, especially during childhood. 1 A number of risk factors have already been identified, such as volatile organic compounds, 2 ultra-fine particles, 3 house dust allergens, 4 environmental tobacco smoke, 5 biomass burning smoke, 6 and chlorination products in swimming pools. 7 The use of wood as heating and cooking fuel can result in elevated levels of indoor air pollution and is considered to be an important public health problem in the developing world. 8 Illustrative for the currently increased attention to wood smoke are the recent classi- fication by the International Agency for Research on Cancer of indoor emissions from biomass fuel (primari- ly wood) as a probable human carcinogen (group 2A) and the recent report by Hosgood et al. confirming the positive association between in-home wood use and the lung cancer risk. 9,10 Epton et al. 11 did not detect a sig- nificant effect of ambient wood smoke particulate air pollution on lung function of healthy school-aged students but they observed associations with respiratory symptoms. In a recent review, Po et al. 12 reported significant associations between solid biomass fuel exposure and the risk of acute respiratory infection in children [odds ratio (OR) 3.53, 95% CI: 1.94–6.43] but these authors found no association with asthma. Barry et al. 13 reported that cooking indoors with wood and coal for more than 6 months significantly increased the Louvain Centre for Toxicology and Applied Pharmacology, Faculty of Medicine, Catholic University of Louvain, Brussels, Belgium. *Correspondence to: Prof. Alfred Bernard, PhD, Louvain Centre for Toxicology and Applied Pharmacology, Faculty of Medicine, Catholic University of Louvain, Avenue E. Mounier 53.02, B-1200 Brussels, Belgium. E-mail: alfred.bernard@uclouvain.be Received 14 March 2011; Accepted 26 June 2011. DOI 10.1002/ppul.21554 Published online in Wiley Online Library (wileyonlinelibrary.com). ß 2011 Wiley-Liss, Inc.