Rus E. Biven

Bone mineral density in normal and asthmatic children

BACKGROUND The largest increase in bone mass occurs during childhood and adolescence. A subnormal bone mass is associated with increased risk of fracture. Bone mass is influenced by height, age, race, exercise, and stage of puberty. It is adversely affected by chronic disease states and corticosteroid use. We performed a cross-sectional study of bone density in children with moderate to severe asthma who were treated with inhaled corticosteroids, inhaled cromolyn, oral corticosteroids, or a combination of these, and we compared them with normal children. METHODS A cross-sectional study of bone density, measured either by dual-photon or dual-energy absorptiometry, was performed on 97 normal white and 30 asthmatic white children, aged 5 to 18. Average daily calcium intake, height, weight, and Tanner stage were determined. The total daily and lifetime doses of inhaled corticosteroids in children with asthma were calculated. T tests, multiple regression, chi square analysis, and analysis of covariance were performed. RESULTS No significant difference in bone density was demonstrated between children with asthma and normal control subjects. No measure (including calcium intake, Tanner stage, daily or lifetime inhaled corticosteroid dose, or duration of illness), except for height and age, provided a significant contribution to the explanation of bone density in children with asthma. CONCLUSION Children and adolescents with moderate to severe asthma, including those treated with inhaled corticosteroids, do not appear to have adversely affected bone mass. There was, however, the possibility of a type II error in this study because of the sample size.

Persistence of increased nonspecific bronchial reactivity in allergic children and adolescents

Nonspecific bronchial reactivity (BR) is commonly associated with asthma. It can be found, however, in subjects with allergic rhinitis. Studies have not been done looking at changes in nonspecific BR in allergic children over time. Therefore, we report on our longitudinal study of BR in allergic children and adolescents. The reported subjects are part of a larger ongoing study in a selected population of families with asthma and of twins. Initiated in 1972, the subjects reported in this study are subjects who have had at least one follow-up visit through 1989 and did not have asthma, but had allergic histories at either their initial visit or follow-up visits. Subjects completed a questionnaire, had skin tests, determination of a serum IgE level, and a determination of nonspecific BR with a methacholine challenge. Subjects were 6 years of age or older or 21 years of age or younger at initial visit. Subjects from families with asthma (N = 76; mean age, 12.09 years; +/- 4.6 SD) and twins (N = 36; mean age, 11.81 years; +/- 3.81 SD) were followed longitudinally, and their age at follow-up visits was not restricted. In this study we observed that, of 106 subjects, 66% initially demonstrated nonspecific BR. At their first and second follow-up visits, 70.4% and 61.3% demonstrated persistence of their BR. These data demonstrate that allergic children and adolescents have increased nonspecific BR. There was not a significant loss of BR over time in the studied subjects.

The usefulness of questionnaire-derived information to predict the degree of nonspecific bronchial hyperresponsiveness

Nonspecific bronchial hyperresponsiveness (BHR) is a hallmark of clinical asthma, but can be present in nonasthmatics as well. The diagnosis of asthma is based on clinical grounds, and no laboratory procedure can definitely establish its presence. This poses a problem in studies of asthma. If epidemiological studies are to provide valid information, the tools used must have a relative degree of predictive or diagnostic ability. This report determined whether the American Thoracic Society-Division of Lung Disease (ATS-DLD) respiratory questionnaire has the ability to predict different degrees of non-specific BHR. In the years 1983-1990, when the ATS-DLD questionnaire was used in our Natural History of Asthma study, 192 subjects completed the ATS-DLD questionnaire and underwent a standardized methacholine challenge. A recursive partitioning analysis of the ATS-DLD questionnaire was able to predict which questions would likely be answered if the subject had nonspecific bronchial reactivity to inhaled methacholine of 100 and 200 breath units. Positive responses for questions concerning treatment for asthma, wheezing, or shortness of breath, and emergency treatment for asthma predicted the presence of increased bronchial reactivity.

Longitudinal measurement of non‐specific bronchial hyperresponsiveness in non‐allergic children and adolescents

Non‐speeifie bronchial hyperresponsiveness (BHR) is intimately associated with the clinical condition recognized as asthma. BHR ean be present, however, in non‐asthmatic subjects, most notable in siblings of sthmatic subjects. What is not well understood, however, is whether inereased bronchial responsiveness, once present, persists over time. In this regard we report on our longitudinal study of BHR in non‐allergic children and adolescents. The reported subjects are part of a larger on‐going study in a selected population of asthma families, normal families, and twins. Initiated in 1972, t he subjects reported here are those who have had at least one follow‐up visit through 1990, and did not have asthma or allergic histories at either their initial or follow‐up(s). Subjects completed a standardized respiratory questionnaire, had skin tests, a serum IgE level and a determination of non‐specific BHR using a methacholine challenge. Subjects were 6 to 21 years at initial visit. Non‐allergic subjects trom asthma families (n = 25), twins (n = 37), and normal families (n = 28) were followed longitudinally, and their age at subsequent visits was not restricted. In this study, we found subjects from asthma families and twins had significantly increased BHR when compared to subjects from normal families. This increased BHR persisted over time and was not influenced by the atopic status of the studied subjects.