Factors predisposing infants to lower respiratory infection with wheezing in the first two years of life.

Abstract

Acute lower respiratory illness (LRI) early in life has been implicated as a factor for adverse respiratory outcomes later in life. Factors that predispose infants to LRI with wheezing have not been conclusively defined. This prospective study assessed factors that might contribute to LRI with wheezing in the first 2 years of life. Seventy-one healthy full-term infants (44 boys, 27 girls) completed the 2-year follow-up. Demographic and environmental factors were evaluated by questionnaire. Respiratory function was assessed by single occlusion technique and rapid thoracic compression technique. Both techniques were performed successfully in 40 infants at 2.6 (+/- 1.4) months old before they developed any episode of LRI. Eighteen infants (25%) developed LRI with wheezing. The first episode of LRI with wheezing occurred in the first year of life in 8 infants, and in the second year of life in 10 infants. There were no significant differences in the demographic or environmental features between infants with or without wheezing LRI, or between infants who acquired LRI with wheezing in the second year of life and those who did not acquire or acquired in the first year of life. Infants from different groups did not differ in airway resistance or maximal flow at functional residual capacity. Infants who developed LRI with wheezing had higher incidence of low values for total respiratory system compliance corrected for body weight compared with those who did not (5/30 versus 6/10, odds ratio = 7.5, 95% confidence interval: 1.53 to 36.7, P = .013). None of the variables of the pulmonary function test could differentiate infants who subsequently developed LRI with wheezing in the first year of life or did not develop any episode of LRI with wheezing from those who developed LRI with wheezing in the second year of life. Differences in lung function in early life may predispose infants to LRI with wheezing in the first 2 years of life.