Chest
Original ResearchAsthmaMethylated Genes in Sputum Among Older Smokers With Asthma
Section snippets
Study Population
In this cross-sectional study, subjects were drawn from 1,861 eligible participants enrolled between 2001 and 2007 in the Lovelace Smokers Cohort, a well-characterized cohort in New Mexico.12, 13 This large cohort disproportionately enrolled women who had ever smoked to study the susceptibility to the development of obstructive lung disease, since women are underrepresented in most studies of airflow obstruction in the United States.14 The catchment area was Albuquerque, New Mexico, and its
Results
Smokers with asthma were more likely to have higher SGRQ scores (ie, greater respiratory symptoms, activity difficulties, and impact on daily life); greater prevalence of postbronchodilator spirometric obstruction26; and lower absolute postbronchodilator FEV1/FVC ratio, as compared with smoker control subjects (Table 1). In addition, smokers with asthma were more likely to be obese than smoker control subjects, in both unadjusted and adjusted analyses (Table 1, Table 2). Of particular note, the
Discussion
Older adult smokers with asthma demonstrate epigenetic changes in sputum DNA, specifically PCDH20 methylation, when compared with control subjects with a similar smoking history. We further demonstrate a synergistic interaction between two methylated genes (PCDH20 and PAX5α) in sputum DNA on the odds for asthma in this population. Interestingly, the epigenetic-asthma associations are not explained by the environmental factors studied, nor are the obesity-asthma associations explained by the
Acknowledgments
Author contributions: Dr Sood: contributed to conception and design of the study, drafting the article or revising it critically for important intellectual content, and approving the version to be published.
Mr Petersen: contributed to acquisition of data or analysis and interpretation of data, drafting the article or revising it critically for important intellectual content, and approving the version to be published.
Dr Blanchette: contributed to acquisition of data or analysis and
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Funding/Support: This study was supported by the State of New Mexico (appropriation from the Tobacco Settlement Fund) and from the National Institutes of Health [Grants K23 HL 094531-01 and CTSA 1ULRR031977-01 (A. S.), RO1 ES015482 (Y. T.), and R01 CA 097356 (S. B.)].