The Science Journal of the American Association for Respiratory Care

2009 OPEN FORUM Abstracts

IS ELEVATED BILIRUBIN A PROTECTIVE FACTOR FOR ASTHMA? AN ANALYSIS OF NHANES 2005-2006 DATA

Venkata Subhash Gorrepati, Pramil Cheriyath, Daniel Fischman; Harrisburg Hospital:Pinnacle Health, Harrisburg, PA

Background: Asthma, an intermittent, potentially life-threatening pulmonary disease, affects nearly 7.7% of the United States population. Previous literature has shown an inverse relation between serum Total Bilirubin (TBili) and atherosclerosis, particularly in men. Thus, we hypothesize that an elevated TBili level will confer a protective effect against asthma. Methods The National Health and Nutrition Examination Survey (NHANES) 2005-2006 is a population- based cross sectional survey of the non-institutionalized United States population. The data was collected in form of questionnaires, physical examination findings, and body fluid laboratory results. The presence of Asthma is assessed by the question “Has the doctor or other health professional ever told you that you have Asthma?” Statistical analysis was performed using a SAS 9.1 Statistical Software PROCSURVEY methodology. Results 4,085 eligible participants were selected after excluding all patients younger than twenty years, those with a history of abnormal liver function tests, or those who disclosed a history of liver disease. After adjusting for age, a TBili level of >14mmol/l was found to be inversely associated with asthma (odds ratio (OR) of 0.74, 95% CI 0.57- 0.97) in males. Although a statistically significant relationship was not found in women, a trend towards a similar inverse relationship was found(OR of 0.75 (95% CI 0.43- 1.29). On adjusting the model for race, tobacco use, and marital status, a statistically significant protective effect for males remained (OR 0.74, with 95% CI 0.54 - 0.99). Conclusion: Our data analysis supports the previously observed, gender-specific protective effect that higher TBili levels convey with respect to Asthma risk. Although the reasons why this effect would not extend to women are not clear, studies do indicate that TBili’s anti-oxidant effects promote beneficial airway remodeling and convey an anti-inflammatory effect. Since a similar effect, where higher TBili levels preferentially protect males against atherosclerosis has been reported in the literature; perhaps, higher estrogen and progestin levels in women counteract the beneficial effects of TBili. Further research is definitely warranted to better delineate this disparity in TBili’s disease preventative properties. Sponsored Research - None

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