Patterns of Growth and Decline in Lung Function in Persistent Childhood Asthma.

BACKGROUND: Tracking longitudinal measurements of growth and decline in lung function in patients with persistent childhood asthma may reveal links between asthma and subsequent chronic airflow obstruction. METHODS: We classified children with asthma according to four characteristic patterns of lung-function growth and decline on the basis of graphs showing forced expiratory volume in 1 second (FEV1), representing spirometric measurements performed from childhood into adulthood. Risk factors associated with abnormal patterns were also examined. To define normal values, we used FEV1 values from participants in the National Health and Nutrition Examination Survey who did not have asthma. RESULTS: Of the 684 study participants, 170 (25%) had a normal pattern of lung-function growth without early decline, and 514 (75%) had abnormal patterns: 176 (26%) had reduced growth and an early decline, 160 (23%) had reduced growth only, and 178 (26%) had normal growth and an early decline. Lower baseline values for FEV1, smaller bronchodilator response, airway hyperresponsiveness at baseline, and male sex were associated with reduced growth (P<0.001 for all comparisons). At the last spirometric measurement (mean [±SD] age, 26.0±1.8 years), 73 participants (11%) met Global Initiative for Chronic Obstructive Lung Disease spirometric criteria for lung-function impairment that was consistent with chronic obstructive pulmonary disease (COPD); these participants were more likely to have a reduced pattern of growth than a normal pattern (18% vs. 3%, P<0.001). CONCLUSIONS: Childhood impairment of lung function and male sex were the most significant predictors of abnormal longitudinal patterns of lung-function growth and decline. Children with persistent asthma and reduced growth of lung function are at increased risk for fixed airflow obstruction and possibly COPD in early adulthood. (Funded by the Parker B. Francis Foundation and others; ClinicalTrials.gov number, NCT00000575.).

The prevalence of environmental exposure to perceived asthma triggers in children with mild-to-moderate asthma: data from the Childhood Asthma Management Program (CAMP).

BACKGROUND: The Childhood Asthma Management Program, a 5-year randomized clinical trial of treatments for childhood asthma, has enrolled and characterized a cohort of 1041 children with mild-to-moderate asthma. OBJECTIVE: We sought to describe self-reported sensitivities and environmental exposures and investigate the relationships between self-report of these exposures as asthma triggers and their prevalence in the home. METHODS: Self-reports of sensitivities and home exposures were obtained by interview with the child or parent. Sensitivities were further assessed by using allergy skin testing (prick or puncture) against a core battery of allergens. Home exposures were further assessed by using analysis of a home dust sample. RESULTS: Environmental exposures were surprisingly common despite self-reported sensitivities to environmental factors. Of patients reporting that cigarette smoking frequently causes asthma symptoms, 26% reported having at least one parent who smokes cigarettes. Thirty-nine percent of patients reporting that exposure to animals frequently causes asthma symptoms live with a furry pet in their home. We found a smaller proportion of homes with a high level of cat allergen (P <.001) among the children who reported that animals frequently or always trigger asthma symptoms compared with those who reported that animals never or occasionally trigger asthma symptoms, suggesting modification of the home environment. No such results were seen for dog exposure. However, clinical symptoms did not reduce exposure to parental cigarette smoking (P =.15), house dust (P =.31), or damp and musty areas (P =.51). CONCLUSION: These data suggest that children with mild-to-moderate asthma are frequently symptomatic and exposed to a wide variety of environmental exposures that are perceived to trigger symptoms by means of self-report. Although environmental modification of asthmatic homes may occur, many children remain exposed to agents that are known to trigger their asthma.

The relationships among environmental allergen sensitization, allergen exposure, pulmonary function, and bronchial hyperresponsiveness in the Childhood Asthma Management Program.

BACKGROUND: Sensitivity and exposure to indoor allergens constitutes a risk factor for the development and persistence of asthma in children. OBJECTIVE: Our purpose was to evaluate the relationship between sensitivity and exposure to inhalant allergens and lung function and bronchial responsiveness in a group of children (n = 1041) aged 8.9 +/- 2.1 years with mild to moderate asthma enrolled in the Childhood Asthma Management Program (CAMP). METHODS: With use of the extensive CAMP baseline cross-sectional data on spirometry, bronchial responsiveness, allergen sensitivities, and household allergen levels, the relationship of sensitization and exposure to allergens to lung function and methacholine sensitivity was evaluated. Children who enrolled in CAMP stopped all antiasthma medication except rescue use of albuterol and prednisone for exacerbations during the 5- to 16-week screening period. During the last 2 of these weeks they underwent spirometry and methacholine challenge. Indoor allergen exposures were determined from questionnaires completed by the parent. Household levels of indoor allergens (mite, cat, dog, cockroach, mold) were determined on house dust samples. Allergen sensitivity was determined by percutaneous skin testing with a standard battery of allergens plus locally important pollen and fungal spores. Lung function and bronchial hyperresponsiveness were compared for children sensitive and not sensitive to both indoor and outdoor allergens on skin testing and, if sensitive, for exposed and not exposed to the allergens to which they were positive on skin testing. RESULTS: There was a strong direct correlation between increased sensitivity to inhaled methacholine and skin test sensitivity to tree, weed, Alternaria, cat, dog, and indoor molds. When the relationship was examined by stepwise regression, the skin test sensitivities showing the strongest associations with the concentration of methacholine that caused a 20% fall in FEV(1) were dog (P =.003), Alternaria (P =.01), and cat (P =.05). Children sensitive to any one of the aeroallergens tested were compared for the presence or absence of exposure to that allergen at the time that the methacholine challenge was performed. Those who were sensitive and exposed to weed and cat had greater methacholine sensitivity than those similarly sensitive but not exposed (P =.003 and P =.02, respectively). CONCLUSIONS: Sensitivity to dog or cat dander or Alternaria by skin testing was associated with increased bronchial responsiveness but not decreased lung function in children with mild to moderate asthma. These findings support the important role that sensitization to certain allergens plays in modulating bronchial responsiveness.