Community Based Study of Adult Onset Asthma

February 17, 2016 updated by: National Heart, Lung, and Blood Institute (NHLBI)
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.

Study Overview

Status

Completed

Conditions

Detailed Description

BACKGROUND:

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.

DESIGN NARRATIVE:

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

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

No older than 100 years (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

No eligibility criteria

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Heart, Lung, and Blood Institute (NHLBI)

Investigators

  • Donald Milton, Harvard University School of Public Health

Publications and helpful links

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General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

February 1, 1999

Study Completion (Actual)

January 1, 2005

Study Registration Dates

First Submitted

May 25, 2000

First Submitted That Met QC Criteria

May 25, 2000

First Posted (Estimate)

May 26, 2000

Study Record Updates

Last Update Posted (Estimate)

February 18, 2016

Last Update Submitted That Met QC Criteria

February 17, 2016

Last Verified

May 1, 2005

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 5087
  • R01HL061302 (U.S. NIH Grant/Contract)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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