Human Molecular Genetics Advance Access originally published online on June 13, 2007
Human Molecular Genetics 2007 16(15):1872-1883; doi:10.1093/hmg/ddm135
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Association between variations in CAT and noise-induced hearing loss in two independent noise-exposed populations
1 Department of Medical Genetics, University of Antwerp, B-2610 Antwerp, Belgium, 2 Department of Audiology and Phoniatrics, Nofer Institute of Occupational Medicine, 91-348 Lodz, Poland, 3 Department of Audiology, and 4 Ahlsén Research Institute, Örebro University Hospital, 701 85 Örebro, Sweden and 5 Department of Genetics and Pathology, Uppsala University, 751 85 Uppsala, Sweden
* To whom correspondence should be addressed at: Department of Medical Genetics, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, B-2610 Antwerp, Belgium. Tel: +32 38202491; Fax: +32 38202566; Email: guy.vancamp{at}ua.ac.be
Received January 31, 2007; Accepted May 16, 2007
Noise-induced hearing loss (NIHL) is an important occupational hazard that results from an interaction between genetic and environmental factors. Although the environmental risk factors have been studied quite extensively, little is known about the genetic factors. On the basis of multiple studies, it was proposed that oxidative stress plays an important role in the development of NIHL. Here, we investigated whether variations (single nucleotide polymorphisms; SNPs) in the catalase gene (CAT), one of the genes involved in oxidative stress, influence noise susceptibility. Audiometric data from 1261 Swedish and 4500 Polish noise-exposed labourers were analysed. DNA samples were collected from the 10% most susceptible and the 10% most resistant individuals. Twelve SNPs were selected and genotyped. Subsequently, the interaction between noise exposure and genotypes and their effect on NIHL were analysed using logistic regression. Significant interactions were observed between noise exposure levels and genotypes of two SNPs for the Swedish population and of five SNPs for the Polish population. Two of these SNPs were significant in both populations. The interaction between predictor haplotypes and tagSNP haplotypes and noise exposure levels and their effect on NIHL were also analysed, resulting in several significant associations. In conclusion, this study identified significant associations between catalase SNPs and haplotypes and susceptibility to development of NIHL. These results indicate that catalase is a NIHL susceptibility gene, but that the effect of CAT polymorphisms can only be detected when noise exposure levels are taken into account.