Community Based Study of Adult Onset Asthma

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00005544
Recruitment Status : Completed
First Posted : May 26, 2000
Last Update Posted : February 18, 2016
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary:
To identify the role of irritant exposure in adult-onset asthma by simultaneously using both clinical and case control methods in a community-based perspective study of asthma incidence.

Condition or disease
Asthma Lung Diseases

Detailed Description:


Asthma incidence is increasing, and in adults work-related exposures may be an important factor-occupational asthma (OA) incidence increased 70 percent over the last decade according to a recent registry based study. The true contribution of occupational exposures to adult-onset asthma is unknown because the methods for measuring OA give conflicting results. Methods based on surveillance of clinically diagnosed OA account for less than one to five percent of adult-onset asthma. However, case-control methods of measuring asthma risk by industry suggest that six to 33 percent of adult-onset asthma is caused by workplace exposures. The conflict may occur because of two factors: physicians often fail to diagnose and report OA, and irritant exposures may increase the risk the risk of asthma without causing cases that meet the clinical definition. Both factors have important implications for proper treatment and prevention of asthma in adults.


Clinical and case control methods were used to identify the role of irritant exposure in adult-onset asthma in a community-based prospective study of asthma incidence. The study cohort was a typical US working population enrolled in an HMO. Additional benefits of the study design were the opportunities to validate a questionnaire for exposure assessment and for detection of work-related asthma. Specifically, the study: 1) Investigated incident cases in a cohort of over 80,000 adults over three years and determined the proportion that met a clinical definition of occupational asthma (OA); 2) Used a nested case-control study to determine the incidence of all asthma by occupation and workplace exposure; 3) Determined whether clinical OA accounted for the excess incidence of adult-onset asthma associated with workplace exposure to sensitizers and irritants; 4) Prospectively followed asthmatics for two years after diagnosis to determine the impact of adult-onset asthma on lung function, employment, income, and quality of life, and to determine whether prognosis differed for clinical OA and for asthma associated with workplace irritant exposure; 5) Tested an intervention designed to increase appropriate clinical diagnosis, and thus secondary prevention of OA.

The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.

Study Type : Observational
Study Start Date : February 1999
Actual Study Completion Date : January 2005

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Asthma

Information from the National Library of Medicine

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Ages Eligible for Study:   up to 100 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
No eligibility criteria

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00005544

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
OverallOfficial: Donald Milton Harvard University School of Public Health

Publications: Identifier: NCT00005544     History of Changes
Other Study ID Numbers: 5087
R01HL061302 ( U.S. NIH Grant/Contract )
First Posted: May 26, 2000    Key Record Dates
Last Update Posted: February 18, 2016
Last Verified: May 2005

Additional relevant MeSH terms:
Lung Diseases
Bronchial Diseases
Respiratory Tract Diseases
Lung Diseases, Obstructive
Respiratory Hypersensitivity
Hypersensitivity, Immediate
Immune System Diseases