National Health and Nutrition Examination Survey (NHANES)
Environmental Cardiopulmonary Disease Group
In the collaboration with the National Institute of Allergy and Infectious Diseases and the National Center for Health Statistics, the Environmental Cardiopulmonary Group developed and implemented an allergy-focused component for the NHANES 2005-2006 survey cycle. The new NHANES component was designed to improve knowledge on complex relationships between allergen and endotoxin exposures, allergic sensitization and allergic diseases, and is the first study to enable such investigations on a nationally representative scale and with sufficient sample size to support comparisons of important subpopulations. Household dust was collected to measure the levels of common indoor allergens and endotoxin, a blood sample was drawn at the NHANES mobile examination center for measurement of total and 19 allergen-specific IgE antibodies, and additional asthma and allergy-related questions were included in the NHANES questionnaires.
Allergic sensitization and disease
While asthma in the U.S. is largely allergic in nature (Arbes et al., J Allergy Clin Immunol., 2007), the group has showed that a significant portion of asthma is independent of IgE levels, either total or specific (Gergen et al., J Allergy Clin Immunol., 2009). The data from NHANES 2005-2006 demonstrated that total IgE predicted asthma only in allergic individuals, but not among non-allergic subjects.
The group has also provided quantitative and qualitative information on sensitization patterns in the general U.S. population and highlighted the importance of different allergens in commonly reported allergic conditions (Salo et al., J Allergy Clin Immunol., 2011). Although food allergy is a large and growing public health concern, the national prevalence and patterns of food allergy are not well characterized. In collaboration with investigators at the National Jewish Medical and Research Center, the group developed estimates of the prevalence of and demographic factors for food allergy, identified high-risk populations, and explored associations with other immune-mediated conditions, including asthma, using data from the NHANES 2005-2006 (Liu et al., J Allergy Clin Immunol., 2010).
Modifying factors for allergic disease
The Environmental Cardiopulmonary Group is actively investigating the role of modifying factors in the development and exacerbation of allergic diseases. The group's collaborative work has showed that obesity is associated with asthma and allergic status in children (Visness et al., J Allergy Clin Immunol., 2009; Visness et al., J Asthma, 2010).
Because systemic inflammation might contribute to the development of allergic disease, the group is investigating the role of systemic inflammation in asthma pathogenesis in more detail. To date, little is known about relationships between cholesterol and inflammatory lung disease, although there is emerging evidence that cholesterol metabolism and inflammation are linked in the lung. In collaboration with Michael Fessler, M.D., the group found novel, inter-racial differences in the relationship between serum cholesterol and allergic disease (Fessler et al., J Allergy Clin Immunol., 2009; Fessler et al., Allergy, 2010). Currently, the group is also working on studies that examine interrelationships between air pollution and allergens with respect to their effects on allergic disease and investigate environmental stressors (e.g., violence) that can influence asthma morbidity in inner-city children.
This nationally representative survey has:
- Provided quantitative and qualitative information on sensitization patterns in the general U.S. population
- Highlighted the importance of different allergens in commonly reported allergic conditions
- Led to a better understanding of the national prevalence and patterns of food allergy
- Increased knowledge on potentially modifiable risk factors of allergic disease
The National Health and Nutrition Examination Survey (NHANES) 2005-2006 allergen/endotoxin data will provide a second data point for the measurement of allergen/endotoxin exposures in homes, the first being established by the National Survey of Lead and Allergens in Housing (NSLAH). The group will investigate exposure trends over time by comparing NHANES 2005-2006 results to those obtained using NSLAH data, after assessing comparability of the populations based on demographic and housing data, as well as accounting for differences in the sampling schemes of the two surveys. Furthermore, the data will allow more detailed analysis of complex relationships between allergen exposure, allergic sensitization, and allergic disease.