Effect Of Obesity On Ozone-Induced Airway Inflammation

NCT ID: NCT00839943

Last Updated: 2012-08-27

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 40 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2006-05-31
• Study Completion Date: 2012-02-29

Brief Summary

The purpose of this study is to compare the effect of ozone exposure on airway reactivity and inflammation in obese vs. non-obese adults.

Detailed Description

Obesity has been shown to be associated with initial onset of asthma in children and increased airway hyperresponsiveness in adults (1,2). An important aspect of these epidemiologic data is that the impact of obesity on asthma is much stronger in females than males. For example, the incidence of asthma after the age of 11 years is five- to sevenfold higher in female children who become obese versus those who remain lean, whereas no such relationship exists for males (3). Recent mouse models of obesity suggest that this condition enhances airway responses to ozone air pollution (4). These mice eat excessively due to a defect in the gene encoding leptin, a satiety hormone produced in adipocytes. Shore et al (4) showed that these leptin-deficient obese mice had greater airway hyperreactivity to i.v. methacholine following ozone exposure compared to lean, wild-type mice. Furthermore, administration of exogenous leptin (which is actually increased in the serum of obese individuals (4)) was shown to enhance ozone-induced cytokine and protein release into BAL fluid of lean, wild type mice (4). Reduced lung volumes and altered breathing patterns in the obese may also contribute to enhanced airway reactivity in these patients (5). Stretch of airway smooth muscle during tidal breathing and especially during deep breaths, i.e. sighs, acts as a potent bronchodilator that might ameliorate ozone-induced bronchoconstriction. The increased chest load associated with obesity may also diminish tidal breathing volumes and frequency of sighs during ozone exposure.

Conditions

Obesity

Keywords

ozone; clean air

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: DOUBLE

Study Groups

ozone

obese vs non-obese women

Group Type: ACTIVE_COMPARATOR

ozone, 0.4 ppm

Intervention Type: OTHER

2 hour ozone exposure, 0.40 ppm

air

obese vs non obese women

Group Type: ACTIVE_COMPARATOR

ozone, 0.4 ppm

Intervention Type: OTHER

2 hour ozone exposure, 0.40 ppm

Interventions

ozone, 0.4 ppm

2 hour ozone exposure, 0.40 ppm

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Twenty (20) non-obese, non-overweight (body mass index, 18 kg/m2 > BMI < 25 kg/m2, waist circumference < 35 inches) subjects and 20 obese (30 kg/m2 > BMI < 38 kg/m2, waist circumference >= 35 inches) volunteer females between 18-35 yrs of age

Exclusion Criteria

• Are female and pregnant or have any reason to believe you might be pregnant.
• Are not between 18 and 35 years old.
• Have a history of asthma or have current hay fever.
• Have ever smoked more than 10 cigarettes (one half pack) a month or smoked during the past 30 days.
• Have a history of acute or chronic cardiovascular disease, chronic respiratory disease, and acute respiratory illness within 4 weeks.
• Have contraindications for performing sustained light exercise.
• You've been in a recent or recurring exposure to a dusty environment at work
• If you are unwilling to refrain from strenuous physical activity for 24 hours before and after each exposure.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 35 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: Yes

Sponsors

University of North Carolina, Chapel Hill

OTHER

Sponsor Role: lead

National Institute of Environmental Health Sciences (NIEHS)

NIH

Sponsor Role: collaborator

Environmental Protection Agency (EPA)

FED

Sponsor Role: collaborator

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

William Bennett, PhD

Role: PRINCIPAL_INVESTIGATOR

University of North Carolina, Chapel Hill

Stephanie London, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

National Institute of Environmental Health Sciences (NIEHS)

Locations

US EPA Human Studies Facility-UNC -CH campus

Chapel Hill, North Carolina, United States

Countries

United States

Other Identifiers

IRB 05-1644

Identifier Type: -

Identifier Source: secondary_id

05-CEMLB-128

Identifier Type: -

Identifier Source: org_study_id