Martha G. Cline

The Course and Prognosis of Different Forms of Chronic Airways Obstruction in a Sample from the General Population

We examined the course and prognosis in subjects selected from the general population who had chronic airflow obstruction at the time of their enrollment in a longitudinal epidemiologic study. Mortality and the rate of change in lung function were analyzed in relation to the initial clinical characteristics of the subjects. Twenty-seven subjects with symptoms and signs of asthma (Group I) had a higher survival rate and a much lower rate of decline in pulmonary function than the 45 subjects in Group III, whose clinical characteristics were more compatible with an emphysematous form of chronic obstructive pulmonary disease (COPD). The 10-year mortality among subjects in Group III (non-atopic smokers without a history of asthma) was close to 60 percent, whereas it was only 15 percent in Group I (atopic subjects or nonsmokers with known asthma). The mean overall rate of decline in forced expiratory volume in one second was 70 ml per year in Group III but less than 5 ml per year in Group I. Forty-five patients (Group II) who did not clearly fit into either Group I or III had intermediate values for survival and decline in pulmonary function. Previous data on mortality from COPD and the rate of progression of the condition, although compatible with our findings in patients who had an emphysematous form of disease, are not applicable to those with an asthmatic-bronchitic form. Better control of the progression of asthmatic bronchitis with therapy may explain its more favorable prognosis.

Early childhood respiratory symptoms and the subsequent diagnosis of asthma

BACKGROUND Respiratory symptoms are frequent in very young children, and the relation of these symptoms to later asthma in some of these children is unknown. OBJECTIVE The aim of the study was to describe the natural history of respiratory symptoms in a community-based sample of young children who were prospectively observed for as long as 11 years. METHODS Subjects were participants in the Tucson Epidemiologic Study of Airways Obstructive Disease. They were under 5 years of age at enrollment and were studied by means of a parent-administered mail survey instrument every 1 to 2 years for 3 to 11 years. RESULTS Among subjects younger than 1 year of age, no single respiratory symptom, such as cough or wheeze only with colds, significantly increased the risk of a subsequent diagnosis of asthma. Among 1- and 2-year-olds, however, those with wheeze only with colds and those with attacks of shortness of breath with wheeze were more likely to be diagnosed with asthma later when compared with children without those symptoms (odds ration = 2.1; p < 0.05 for wheeze only with colds). At ages 3 to 4 years, symptoms were even more strongly associated with subsequent asthma (odds ratio = 7.2; p < 0.0001 for attacks of shortness of breath with wheeze). CONCLUSION Although respiratory symptoms reported by parents very early in life are not significantly associated with future asthma, those symptoms that begin at or persist through ages 3 to 4 years are.

Antecedent features of children in whom asthma develops during the second decade of life

In this report we compare 36 subjects in whom asthma was first diagnosed between the ages of 10 and 20 with 297 control subjects. All subjects were studied at age 5 to 9. Among the subjects who acquired a new diagnosis of asthma (NDA), the diagnosis was usually preceded by lower respiratory tract symptoms (31 of the 36 subjects had respiratory symptoms or a diagnosis of rhinitis or chronic bronchitis before asthma developed). Among those tested, more of those with NDA had positive allergy skin test results (56.5%) before diagnosis than control subjects (29.6%; p < 0.05), and the subjects with NDA had higher levels of serum IgE than control subjects (mean log serum IgE = 2.27 in subjects with NDA, 1.76 in control subjects; p < 0.05). Pulmonary function tests revealed no significant differences in the groups before diagnosis. Using logistic regression, we determined that wheezing, cough, a diagnosis of chronic bronchitis, and a positive allergy skin test result were independent risk factors for asthma. When combinations of variables were used, subjects with wheezing and a positive allergy skin test result, cough and a positive test result, and also those with a prior diagnosis of chronic bronchitis alone were at highest risk of a subsequent diagnosis of asthma.

Familial Aggregation and Segregation Analysis of Snoring and Symptoms of Obstructive Sleep Apnea

To investigate possible modes of inheritance that would explain familial aggregation in obstructive sleep apnea (OSA), familial correlation and segregation analyses were performed on data derived from 584 pedigrees with 2019 cases enrolled in the Tucson Epidemiologic Study of Obstructive Airways Disease (TESOAD) who were at least 10 years of age and who had information pertaining to snoring and daytime sleepiness. Data were obtained from the 9th (May 1984 to October 1985) and 12th (February 1990 to October 1992) surveys of the TESOAD, which is a random, stratified sample of the non-Hispanic Caucasian population of Tucson, Arizona. A snoring phenotype was considered present if it occurred on at least some nights. A “sleep apnea” phenotype was constructed if participants snored and experienced daytime sleepiness. Familial correlations for snoring showed significant mother-child and sibling correlations but not father-child correlations. For sleep apnea, significant parent-daughter but not parent-son or sibling correlations were observed. Segregation analyses for snoring with regressive familial effects and sibling, age, and obesity covariates showed no evidence for mendelian transmission. However, additional familial effects were present that suggested phenotype aggregation from polygenic or environmental factors, or both. For the sleep apnea phenotype, similar segregation analyses indicated that mendelian dominant or codominant models were possible. However, the analyses also suggested that a nongenetic model fit the data as well. In addition, consistent with the familial correlations, specific maternal- and sibling-related effects remained even after inclusion of age, gender, and obesity covariates. These data support the concept that inheritable or shared environmental factors contribute to the development of OSA and that maternal components may be more important than paternal ones.