There is evidence that dietary factors may be important in the etiology of asthma and chronic obstructive pulmonary disease (COPD) in both smokers and nonsmokers. However, the existing data on the role of diet in the etiology of asthma and COPD come predominantly from cross-sectional studies. Prospective data are needed to properly address the role of diet in the development of asthma and COPD. Air pollution clearly exacerbates existing lung disease, but a role in the incidence of asthma and COPD in adults is not established. Prospective data are necessary to properly examine this association, but such data are few. Genetic factors are likely to play a role in modulating the effects of diet, smoking, and ambient air pollution on the risk of adverse respiratory outcomes in adults. Genetic factors may influence the metabolism of nutrients in food that are responsible for health effects. Both diet and genetics may combine to influence susceptibility to adverse effects of air pollution. Effects of air pollution are likely to be weak when averaged over whole populations and identification of susceptibility factors will help to clarify health consequences of air pollution. I am establishing several high-quality population resources to prospectively investigate effects of air pollution, diet, genetics and their interactions in relation to asthma and COPD in adults. The first population is a cohort of 63,000 older adults of Chinese ethnicity in Singapore. The cohort was established with NCI extramural funding to examine the relationship between diet and cancer. I have expanded the study to include the assessment of asthma and chronic bronchitis and expanded the assessment of environmental exposures. The Singapore Chinese cohort is of particular interest because of the prospective collection of risk factor data. Another major strength of the study is the high quality dietary assessment, which was developed specifically for, and validated in, this population. The Singapore cohort also follows dietary patterns quite distinct from the Western populations included in existing adult respiratory studies. Other strengths of the study are the large proportion of nonsmokers and the availability of genetic samples. In FY2005, we completed a validation of incident asthma so that we will be able to begin analyses of asthma. We published our second paper from the cohort -- a study showing that early life exposure to environmental tobacco smoke is related to the development of chronic cough and phlegm in adulthood. We found that adult intake of fiber, a protective factor for respiratory symptoms in this cohort, slightly mitigated the effects of early exposure. We have also submitted a manuscript on occupational exposure and respiratory symptoms and illness in the cohort. We have also submitted a paper on the relation between complex dietary patterns, using principal components analysis and respiratory disease in this cohort. The second study is a collaboration with another extramurally funded cohort, the Atherosclerosis Risk in Communities (ARIC) study. We are examining traffic-related air pollution in relation to a range of respiratory and cardiovascular endpoints. The ARIC study is a cohort of 16,000 adults assembled from 1987-1989 in four US communities. It is one of the few large studies with longitudinal measures of pulmonary function and measures of heart-rate variability. Preliminary results indicated associations between traffic related air pollution and pulmonary function along with respiratory symptoms. We also are finding associations with several cardiovascular disease outcomes. We are preparing manuscripts from this work. We are also working on refinements to our exposure assessment. The third population is the Sister Study. This NIEHS cohort will have 50,000 sisters of women with breast cancer. I have added nonmalignant respiratory disease questions to the questionnaire with the aim of examining gene-environment interaction in relation to respiratory disease in this cohort. Because the respiratory outcomes of interest have proved to be common in analysis of the first 10,000 respondents, I plan to begin analyses of risk factors for asthma and respiratory symptoms after 15,000 women have been recruited during FY2006. The final population is the Agricultural Health Study at NIEHS. I am involved with a team that is analyzing questionnaire data from this study and planning for the next round of follow-up. As we collect better respiratory data on the next round of follow-up, I am interested in examining gene-environment interaction with respiratory outcomes in the study. I have been integrally involved in designing the respiratory section of the follow-up questionnaire and planning collection of objective outcome data.
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