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Children's Respiratory Study (CRS)
The Children’s Respiratory Study (CRS) was started in 1980 with the goal of exploring the early life origins of asthma. Between 1980 and 1984, 1246 healthy infants were enrolled in the study at birth making the CRS a population based, non-selected, prospective birth cohort study.
The CRS has been continuously funded by the National Institutes of Health through the present. Starting at birth, samples and questionnaires have been collected from the enrolled children at regular intervals. There have been 5 “In Depth” Evaluations completed at ages 6, 11, 16, 22, and 26 years. In Depth 6 is currently in progress and the participants are on average 32 years old. At each In Depth Evaluation, the participants performed pulmonary function testing (PFT), bronchial hyper-responsiveness testing (methacholine or cold air challenge), allergy skin prick tests to local aeroallergens. In some of the evaluations, peak flow variability testing, exhaled nitric oxide measurement and sputum induction were also included in the protocols. In addition, blood samples were collected for complete blood cell counts, DNA extraction, and total immunoglobulin E measurement. Blood samples were also collected at birth (umbilical cord) and at 9 months of age. Additional respiratory health questionnaires were completed at ages 2, 3, 8, 13, 18, 24, and 29 years.
One of the strengths of the CRS study is the detailed information collected about lower respiratory illnesses (LRI) during the first 3 years of life (bronchiolitis, pneumonia, croup and others). In case of symptoms compatible with LRI, children were seen by a pediatrician and symptoms as well as viral or bacterial etiology of each LRI were determined. Parents and siblings also completed respiratory questionnaires, pulmonary function testing, allergy skin prick testing and a blood sample collection.
Of the 1246 CRS participants, 821 have adult respiratory data between ages 22 and 29 years. Our main measure of asthma is derived from the questionnaires and is defined as a physician diagnosis of asthma with episodes or attacks of asthma and/or wheeze during the previous year. We define frequent asthma as four or more episodes during the previous year and infrequent asthma as 1-3 episodes during the previous year. As adults, 12% (n=97) of the CRS participants have frequent asthma and 18% have infrequent asthma (n=148). In addition, 6% (n=47) report frequent wheeze without a diagnosis of asthma and 24% (n=195) report infrequent wheeze without a diagnosis of asthma. Overall, 41% (n=334) of CRS participants do not report asthma and wheeze symptoms as adults.
Phenotype data for each CRS contact, numbers correspond to participants with data
Wayne J. Morgan, MD