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Risk factors for asthma and timing of exposure among first generation Arab immigrants: a pilot effort to elucidate the role of exposure to risk factors over multiple life stages
JOHNSON, M. M., J. O. NRIAGU, A. Hammad, AND H. Jamil. Risk factors for asthma and timing of exposure among first generation Arab immigrants: a pilot effort to elucidate the role of exposure to risk factors over multiple life stages. Presented at 5th National Conference on Health Issues in the Arab American Community, Dearborn, Michigan, Dearborn, MI, November 06 - 07, 2008.
Considerable controversy exists over the role of aero-allergens in asthma etiology. Some studies show increased risk with microbe and allergen exposure, while others show decreased risk. These discrepancies may be explained by timing of exposure. Previous research suggests that exposure during childhood may impact the immune system during critical developmental stages. Alternately, type of allergen, rather than timing of exposure, may playa critical role in determining asthma risk. Immigrant populations provide a unique opportunity to explore these issues. There is also growing evidence that lifestyle changes associated with westernization may influence asthma outcomes among immigrant communities. The Arab American Environmental Health Project (AAEHP) collected information about self¬reported asthma and lifetime exposure history among 159 adult Arab Americans living in metro Detroit. Over 95% of the participants were first generation immigrants. Life history divided into 9 age categories: 0-5, 6-12, 13-19,20-29,30-39,40-49,50-59,60-69, 70+ years. Approximately 30 risk factors for asthma including urban residence, pet ownership, immunization, respiratory illness, proximity to roadways, wood burning stove, and SES surrogates (electricity, television, air conditioning, and refrigerator) were examined for multiple life stages. Pet ownership in childhood was positively associated with asthma in multivariate models. Variables included as SES surrogates such as presence of television, air conditioning and refrigerator in the home were inversely associated with asthma in multivariate models. There was also some evidence to suggest that urban residence was inversely associated with asthma. Urbanization and lifestyle changes associated with westernization have been cited as risk factors in the asthma literature. In contrast, urban residence and factors potentially associated with westernization appeared to playa protective role in this community. The role of pet ownership in asthma etiology has been controversial; some studies have reported a positive association, while others have suggested a protective effect. In this study population, pet ownership (in all age groups) was positively associated with asthma. The current analyses were limited by the method for exposure assessment. Due to the small sample size, there were many variables with homogeneous responses, which reduced our ability to examine the impact of those potential risk factors. Recall bias may also have impacted the responses. Most importantly, inability to remember early childhood exposures may have significantly impacted our findings. Early childhood was collapsed into a single category (ages 0-5 years) to address this concern; however, it is likely that information provided for later life stages may be more accurate. Despite considerable limitations, this pilot effort suggests a need for further exploration of exposure histories among immigrant populations. AlthoughthisworkwasreviewedbyEPA andapprovedforpublications, it maynotnecessarily reflect official Agency policy.