Abstract:
Introduction: The development of an asthma-like condition characterized by episodic cough, dyspnea, chest tightness, and variable airflow obstruction has been described among workers in aluminum smelter potrooms. No specific etiologic agent has been identified and the pathophysiologic mechanisms involved remain poorly understood. It has long been suspected that there is a heritable component to asthma. In the past decade, intensive research efforts have identified chromosomal regions and specific candidate genes that are associated with asthma in the general population. These genes include the High Affinity IgE receptor, Beta2-Adrenoreceptor, Clara Cell Secretory Protein, and Tumor Necrosis Factor. The aim of this study was to determine if the polymorphisms associated with asthma in the general population are associated with the development of asthma while employed in an aluminum smelter potroom.
Methods: A nested case-control study was conducted among members of an inception cohort of newly hired aluminum potroom employees. Workers who developed new asthma-like symptoms and/or worsening bronchial hyperresponsiveness were compared to cohort members who did not develop an asthma-like condition. Buccal swab DNA samples were obtained from each study participant and the genotype of each of the following candidates genes was determined: clara cell secretory protein, Beta2-adrenoreceptor, high affinity IgE receptor, and tumor necrosis factor. Chi squared analysis and the calculation of Odds Ratios were used to test for associations between clinical status and genotype at each of the candidates genes.
Results: 13 cases and 39 controls were included in the study. No associations were found between the development of an asthma-like condition during employment in an aluminum smelter potroom and genotype at four candidate genes for asthma.
Conclusion: The asthma-like condition associated with work in an aluminum smelter potroom remains poorly understood. Future investigations of genetic susceptibility and occupational asthma should include larger numbers of subjects and be directed towards those candidate genes that are consistently associated with asthma in the medical literature.