The Association between Asthma and Allergic Symptoms in Children and Phthalates in House Dust: A Nested Case-Control Study
Carl-Gustaf Bornehag,1,2,3 Jan Sundell,2 Charles J. Weschler,2,4 Torben Sigsgaard,5 Björn Lundgren,1 Mikael Hasselgren,3 and Linda Hägerhed-Engman1 1Swedish National Testing and Research Institute, Borås, Sweden; 2Technical University of Denmark, Lyngby, Denmark; 3Public Health Science, Karlstad University, Karlstad, Sweden; 4University of Medicine and Dentistry New Jersey-Robert Wood Johnson Medical School and Rutgers University, Piscataway, New Jersey, USA; 5Aarhus University, Aarhus, Denmark
Abstract
Global phthalate ester production has increased from very low levels at the end of World War II to approximately 3.5 million metric tons/year. The aim of the present study was to investigate potential associations between persistent allergic symptoms in children, which have increased markedly in developed countries over the past three decades, and the concentration of phthalates in dust collected from their homes. This investigation is a case-control study nested within a cohort of 10,852 children. From the cohort, we selected 198 cases with persistent allergic symptoms and 202 controls without allergic symptoms. A clinical and a technical team investigated each child and her or his environment. We found higher median concentrations of butyl benzyl phthalate (BBzP) in dust among cases than among controls (0.15 vs. 0.12 mg/g dust). Analyzing the case group by symptoms showed that BBzP was associated with rhinitis (p = 0.001) and eczema (p = 0.001), whereas di(2-ethylhexyl) phthalate (DEHP) was associated with asthma (p = 0.022). Furthermore, dose-response relationships for these associations are supported by trend analyses. This study shows that phthalates, within the range of what is normally found in indoor environments, are associated with allergic symptoms in children. We believe that the different associations of symptoms for the three major phthalates—BBzP, DEHP, and di-n-butyl phthalate—can be explained by a combination of chemical physical properties and toxicologic potential. Given the phthalate exposures of children worldwide, the results from this study of Swedish children have global implications. Key words: allergy, asthma, BBzP, children, DEHP, homes, phthalates. Environ Health Perspect 112:1393-1397 (2004). [Online 15 July 2004]
Address correspondence to C.G. Bornehag, Public Health Sciences, Karlstad University, 651 88 Karlstad, Sweden. Telephone: +46-54-700-25-40. Fax: +46-54-700-25-23. E-mail: carl-gustaf.bornehag@kau.se
The study was supported by the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas), Swedish Asthma and Allergy Association's Research Foundation, the Swedish Foundation for Health Care Sciences and Allergy Research, and European Council of Plasticizers and Intermediates.
The authors declare they have no competing financial interests.
