A Brief Targeted Review of Susceptibility Factors, Environmental Exposures, Asthma Incidence, and Recommendations for Future Asthma Incidence Research

Abstract

Relative to research on effects of environmental exposures on exacerbation of existing asthma, little research on incident asthma and environmental exposures has been conducted. However, this research is needed to better devise strategies for the prevention of asthma. The U.S. Environmental Protection Agency (EPA) and National Institute of Environmental Health Sciences held a conference in October 2004 to collaboratively discuss a future research agenda in this area. The first three articles in this mini-monograph summarize the discussion on potential putative environmental exposure; they include an overview of asthma and conclusions of the workshop participants with respect to public health actions that could currently be applied to the problem and research needs to better understand and control the induction and incidence of asthma, the potential role of indoor/outdoor air pollutants in the induction of asthma), and biologics in the induction of asthma. Susceptibility is a key concept in the U.S. EPA “Asthma Research Strategy” document and is associated with the U.S. EPA framework of protecting vulnerable populations from potentially harmful environmental exposures. Genetics, age, and lifestyle (obesity, diet) are major susceptibility factors in the induction of asthma and can interact with environmental exposures either synergistically or antagonistically. Therefore, in this fourth and last article we consider a number of “susceptibility factors” that potentially influence the asthmatic response to environmental exposures and propose a framework for developing research hypotheses regarding the effects of environmental exposures on asthma incidence and induction.

Indoor airborne fungi and wheeze in the first year of life among a cohort of infants at risk for asthma

“…Evidence suggests that the development of asthma occurs primarily during early childhood and involves both genetic and environmental factors including biologics (e.g., allergens, viruses, bacterial products). The timing and ''dose'' of the environmental exposures and the interaction with genes and other susceptibility factors (e.g., breast-feeding, lifestyle) during specific developmental periods appear critical to the induction of asthma (Martinez, 2003;Yeatts et al, 2006;Gilmour et al, 2006;Zeldin et al, 2006;Selgrade et al, 2006). It is likely that fungal allergens eliciting immunological and airway changes during this critical developmental period are dependent in part, on the geographic area and climate (Martinez, 2002), perhaps accounting for the variety of fungal taxa-respiratory symptom associations which have been observed.…”

Cancer risk in hospitalised asthma patients

“…The annual incidence rate for adults has been 2.2 cases per 1000 persons in the Nordic countries (Toren et al, 2004). An improved hygiene and a drop in exposure to viral and bacterial infections are thought to explain part of the increase (Maddox and Schwartz, 2002;Oh et al, 2004;Yeatts et al, 2006). An enhanced TH2 immune response followed by an increased production of cytokines of type IL-4 and IL-5 are thought to contribute to the development of asthma (Ngoc et al, 2005).…”

Risk of Cancer among the Offspring of Women Who Experienced Parental Death during Pregnancy

“…The immune system develops during the intrauterine period, and it may be sensitive to maternal stress hormones (22). Hormonal changes due to stressful events during pregnancy may activate viruses, such as the EBV or latent human T-cell lymphotropic viruses, or they could intervene with the development of the immune system of the fetus (4,23).…”