Genetics of Airway Responsiveness and Lung Function

This study has been completed.
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI) Identifier:
First received: May 25, 2000
Last updated: June 23, 2005
Last verified: August 2004
To perform a genome-wide search for genes affecting two phenotypes related to asthma and chronic obstructive pulmonary disease (COPD) in a Chinese population.

Lung Diseases, Obstructive
Chronic Obstructive Pulmonary Disease

Study Type: Observational

Resource links provided by NLM:

Further study details as provided by National Heart, Lung, and Blood Institute (NHLBI):

Study Start Date: July 1997
Estimated Study Completion Date: June 2002
Detailed Description:


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.


Genders Eligible for Study:   Male
Accepts Healthy Volunteers:   No
No eligibility criteria
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Please refer to this study by its identifier: NCT00005537

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
Investigator: Xiping Xu Brigham and Women's Hospital
  More Information

Publications: Identifier: NCT00005537     History of Changes
Other Study ID Numbers: 5071
Study First Received: May 25, 2000
Last Updated: June 23, 2005
Health Authority: United States: Federal Government

Additional relevant MeSH terms:
Lung Diseases
Lung Diseases, Obstructive
Pulmonary Disease, Chronic Obstructive
Respiratory Tract Diseases processed this record on November 30, 2015