Wegienka G, Havstad S, Zoratti EM, Ownby DR, Johnson CC. Ann Allergy Asthma Immunol. 2009;102(1):29–34
PURPOSE OF THE STUDY. To calculate the age-specific incidence of wheeze and to determine whether wheezing at particular ages in early life is predictive of abnormal pulmonary function (airway hyperreactivity [AHR] and percentage of predicted forced expiratory volume in 1 second [FEV1]) and current asthma at age 6 to 7 years.
STUDY POPULATION. The Childhood Allergy Study is an ongoing study evaluating environmental determinants of childhood allergies and asthma. An unselected birth cohort consisting of 835 term infants born to women >18 years of age belonging to a health maintenance organization in the suburban Detroit, Michigan, area between 1987 and 1989 was followed prospectively with annual interviews through age 6 to 7 years. The children were then seen in the clinic for further evaluation at age 6 to 7 years. Ninety-three percent of the children were born to mothers who identified themselves as white.
METHODS. Current asthma was defined as ever having a physician diagnosis of asthma and symptoms of asthma or use of asthma medication in the previous year. Spirometry and methacholine challenge were performed during the clinic visit at 6 to 7 years of age. The provocative concentration of methacholine causing a 20% decrease in FEV1 was considered abnormal at <16 mg/mL. Methacholine challenge and spirometry results for children with current asthma were excluded from analysis.
RESULTS. Age-specific wheeze incidence according to parental report was highest at age 1 year (27.2%). The second highest incidence was at age 6 years (13.4%). Wheeze incidence was higher for boys than for girls at all ages (1–6 years), and the 6-year cumulative incidence of wheezing was higher for boys than for girls (66.2% vs 47.6%). At age 6 to 7 years, 7.3% of the children had current asthma (boys: 10.3%; girls: 4.5%). Abnormal AHR was seen in 35.7% of patients without current asthma at age 6 to 7 years, compared with 75% of those with current asthma. The percentage of predicted FEV1 was normal in all children but was higher in those without current asthma (94.5%) than in those with current asthma (87.9%). Wheezing at ≤3 years (early wheeze) was not associated with current asthma at age 6 to 7 years in either boys or girls. Wheezing at >4 years (late wheeze) was associated with current asthma at age 6 to 7 years. Neither early nor late wheezing was associated with abnormal AHR or percentage of predicted FEV1 at age 6 to 7 years. History of childhood eczema or parental asthma and cord blood immunoglobulin E levels did not affect any of the associations.
CONCLUSIONS. Wheezing in the first 3 years was not associated with current asthma at age 6 to 7 years and was not associated with AHR or FEV1 at age 6 to 7 years.
REVIEWER COMMENTS. The data from this unselected cohort are similar to those seen in the United States (Tucson Children's Respiratory Study) and Europe, with the lack of association of wheeze in early childhood with subsequent asthma. The Tucson study determined that certain characteristics of atopy in the child and atopy and asthma in the parents were predictive of subsequent asthma, which led to the development of the Asthma Predictive Index. In the current study, cord blood immunoglobulin E levels, childhood eczema, and parental asthma history did not affect the negative associations of wheezing in the first few years with subsequent development of asthma. Wheezing at >4 years was associated with current asthma at age 6 to 7 years.
- Copyright © 2009 by the American Academy of Pediatrics