Phthalate-induced oxidative stress and association with asthma-related airway inflammation in adolescents

Carmen Franken, Nathalie Lambrechts, Eva Govarts, Gudrun Koppen, Elly Den Hond, Daniella Ooms, Stefan Voorspoels, Liesbeth Bruckers, Ilse Loots, Vera Nelen, Isabelle Sioen, Tim Nawrot, Willy Baeyens, N. Van Larebeke, Greet Schoeters

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

Background

In Belgium, around 8.5% of the children have asthmatic symptoms. Increased asthma risk in children has been reported in relation to exposure to phthalate plasticizers but the underlying mechanisms are largely unknown.
Aim

The aim of this study was to identify if oxidative stress, assessed by excision of 8-hydroxydeoxyguanosine (8-OHdG) from damaged DNA, is an intermediate marker for the association between phthalate exposure and doctor-diagnosed asthma.

Material and methods

In 418 14–15-year-old youngsters, recruited as a representative sample of residents of Flanders (Belgium), personal exposure to phthalates was assessed by measuring phthalate metabolites in urine: mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-n-butyl phthalate (MnBP), mono-benzyl phthalate (MBzP), mono-isobutyl phthalate (MiBP) and mono-ethyl phthalate (MEP). Analysis of 8-OHdG in urine was used as a sensitive biomarker of oxidative stress at the level of DNA. The presence of doctor-diagnosed asthma was elicited by a self-administered questionnaire. Associations were assessed using multiple linear and logistic regression models. Mediation was tested using Baron and Kenny's regression approach.

Results

A significant increased risk of a youngster being diagnosed with asthma was found for both urinary MnBP (metabolite of dibutyl phthalate (DBP)) and the sum of the three di(2-ethylhexyl) phthalate metabolites (ΣDEHP = MEHP + MEHHP + MEOHP), with respective odds ratio of 1.84 [95% CI: 1.02, 3.32] for MnBP and 1.94 [95% CI: 1.07, 3.51] for ΣDEHP. In addition, we observed significant associations between all urinary phthalate metabolites and increased urinary levels of 8-OHdG. The associations were stronger in girls than in boys. We did not found evidence that 8-OHdG was associated with doctor-diagnosed asthma.

Conclusion

The results of our study are in line with other findings from epidemiological surveys and raise further concern about DEHP and DBP as risk factors for asthma, however, the underlying mechanisms are not yet well understood.
Original languageEnglish
Pages (from-to)468-477
Number of pages10
JournalInternational Journal of Hygiene and Environmental Health
Volume220
Issue number2
Early online date30 Jan 2017
DOIs
Publication statusPublished - Apr 2017

Keywords

  • 8-hydroxydeoxyguanosine
  • Doctor-diagnosed asthma
  • Human biomonitoring
  • Oxidative stress
  • Phthalate

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