The purpose of this study is to examine whether there are higher levels of cysteinyl leukotrienes in obese subjects than in non-obese subjects. Cysteinyl leukotrienes are pro-inflammatory substances that cause asthma by narrowing the airways of the lung. The investigators want to see if subjects with increased fat stores and therefore increased leptin, which is a fat-related protein that regulates leukotrienes, have increased levels of leukotrienes in the blood, lung and urine. The investigators would also like to determine the relationship between cysteinyl leukotrienes and exhaled nitric oxide levels in asthmatics with and without obesity. Nitric oxide is anti-inflammatory and suppresses leukotriene synthesis.

This is a cross-sectional observational study to characterize the association between obese asthmatics and the inflammatory mediators cysteinyl leukotrienes. Our hypothesis is that altered adipokine levels in obesity result in augmented cysteinyl leukotriene synthesis that play a significant role in the pathogenesis of asthma in these subjects.

Inclusion Criteria:

• 18-65 yr old adults with asthma, non-smoking for at least one year
• Healthy non-smoking adults, aged 18-65 without asthma
• Heavy subjects with BMI > 30 kg/m2
• Subjects with normal weight (BMI between 20-25 kg/m2)
• Subject not taking anti-leukotriene therapy (Singulair, Accolate, Zyflo)

Exclusion Criteria:

• No chronic oral steroid use
• No recent history of infection
• No recent history of flare of lung disease

UM Housing Residents/Student Dorms UM Human Research Recruiting Registry (e.g., ENGAGE - http://www.med.umich.edu/engage/) Department or unit-specific research recruiting registry (provide UM IRB project number below) Other UM subject pools (describe below) Patients or their medical records from the UM Health System or any other UM health care provider (e.g., School of Dentistry, University Health Service, University Center for Language and Literacy)