Genetics of Airway Responsiveness and Lung Function

This study has been completed.
Sponsor:
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)
ClinicalTrials.gov Identifier:
NCT00005537
First received: May 25, 2000
Last updated: June 23, 2005
Last verified: August 2004

May 25, 2000
June 23, 2005
July 1997
Not Provided
Not Provided
Not Provided
Complete list of historical versions of study NCT00005537 on ClinicalTrials.gov Archive Site
Not Provided
Not Provided
Not Provided
Not Provided
 
Genetics of Airway Responsiveness and Lung Function
Not Provided

To perform a genome-wide search for genes affecting two phenotypes related to asthma and chronic obstructive pulmonary disease (COPD) in a Chinese population.

DESIGN NARRATIVE:

Airway responsiveness and lung function, endpoints with a strong genetic basis, are central to the obstructive airway diseases (asthma and COPD). In contrast, the dissection of the underlying genes requires unique sample resources, accurate and comprehensive phenotyping, and an efficient study design. To address to this three-pronged challenge, a genomic screen brought together a large, homogenous, mostly untreated sample from Anhui, China, a wealth of expertise in asthma phenotypes, and a potent study design based on extreme discordant sib pairs.

Since this approach utilized an extant asthmatic family population, no support for data collection was required. The primary focus of the study was two intermediate phenotypes related to asthma and COPD: airway responsiveness (characterized by increased responsiveness to histamine methacholine or other nonspecific agonists and measured by the slope of the dose response relationship) and forced expiratory volume in 1 second (FEV1). Since both traits are continuous, the appropriate study design considered only siblings with extremely discordant phenotypes. For many studies, this strategy was not feasible due to the thousands of families that must be phenotyped to identify a sample of such siblings. The plan was to utilize the organization of a well-established network in China to collect 150 extreme discordant sib pairs of each intermediate phenotype. For airway responsiveness, the estimated power from this sample, equivalent to roughly 600 concordant sib pairs, was intended to surpass the power of all existing studies, including the U.S. Collaborative Study on the Genetics of Asthma. Further, with similar power, this was the first study to test for linkage to FEV1. Moreover, to further augment power, potential phenotypic heterogeneity was reduced by stratifying the analyses by total and specific serum IgE levels, skin test reactivity, peripheral blood eosinophilia, respiratory symptoms, age, gender, bronchodilator response, and cigarette smoking.

Observational
Not Provided
Not Provided
Not Provided
Not Provided
Not Provided
  • Asthma
  • Lung Diseases, Obstructive
  • Chronic Obstructive Pulmonary Disease
Not Provided
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
Not Provided
June 2002
Not Provided

No eligibility criteria

Male
Not Provided
No
Contact information is only displayed when the study is recruiting subjects
Not Provided
 
NCT00005537
5071
Not Provided
Not Provided
National Heart, Lung, and Blood Institute (NHLBI)
Not Provided
Investigator: Xiping Xu Brigham and Women's Hospital
National Heart, Lung, and Blood Institute (NHLBI)
August 2004

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP