Abstracts: ISEE 22nd Annual Conference, Seoul, Korea, 28 August-1 September 2010: Interaction of Environmental and Genetic Factors in Health and Development
Occupational asthma (OA) is a good model for studying the natural history of adult onset asthma, and for investigating gene-workplace exposure interactions. Most studies on genetic polymorphisms involved in this disease were conducted among workers, none dealt with apprentices. Our aim is to assess whether polymorphisms of interleukins (IL) (1, 4, 5, 13) and tumor necrosis factor-alpha (TNFA), play a role in the incidence of bronchial hyperresponsiveness (BHR) among bakery and hairdressing apprentices, 2 populations at high risk of OA.
A nested case-control study was conducted within a cohort study conducted in 6 vocational schools. Three follow-up visits were scheduled every 6 months after an inclusion examination. Cases were subjects with BHR determined by a metacholine challenge test that was conducted at every visit (V1–V4). DNA was extracted from the nasal lavage fluid. Polymorphisms (IL-1(alpha, beta) IL-13 Arg130Gln, IL-4R Ser478Pro and Gln551Arg, IL-5C-703T and TNFA-308G>A) were evaluated by real-time PCR (Light-Cycler, Roche).
Altogether, 387 subjects had at least 3 visits, including V1 and V4. The mean age at inclusion was 16.9. Most hairdressers were females (92.8%) while most bakery and pastry cooks were males (87.4%). At the end of the follow-up, 71 cases (18.35%) showed an incident BHR. Host factors associated with this incidence differ across the training tracks. Atopy is a determinant among subjects exposed to flour dust (P = 0.01). The genotype TNFA-308GG was significantly associated with BHR (P = 0.03), with effect in nonatopic subjects. Also, significant interactions between these polymorphisms differ between the training track among the nonatopic subjects. Indeed an increased risk of BHR was observed among hairdressers displaying the combined genotypes TNFA-3086GG/IL1-alpha-TT (P = 0.03) and subjects exposed to flour dust displaying the combined genotypes TNF-308GG/IL5-TT (P = 0.04) and IL1-beta-TT/IL-13-GA (P = 0.01).
This study shows an interaction between early occupational exposure and genetic predisposition, on the risk of BHR.