A Longitudinal Analysis on the Association Between Antibiotic Use, Intestinal Microflora, and Wheezing During the First Year of Life

Objective. To examine the association between the intestinal flora at the age of three weeks and wheezing during the first year of life in a prospective birth cohort study. Methods. The Asthma and Allergy study is a prospective birth cohort study. A total of 154 children were recruited through maternity clinics. Selection criteria were vaginal delivery at term and uncomplicated perinatal period. Questionnaires were collected with data on the parents, including demography, smoking, and asthma. Data of the child on demographic factors, respiratory symptoms, and risk factors for asthma were collected at the ages of 3 weeks and 6 and 12 months. A fecal sample was collected at 3 weeks of age. Results. The frequency of wheezing averaged on 11.8%, 18.4%, and 23.5% at the three time points. In univariate analyses, increasing total concentration of anerobic bacteria were associated with increased odds of wheezing. Furthermore, several trends were observed between wheezing and Bifidobacterium and Clostridium. A final model showed a significant association between wheezing during the first year of life and antibiotic use, total concentration of anerobic bacteria, while increasing concentrations of Clostridium were protective of wheezing. Conclusion. This study demonstrated an association between antibiotics, anerobic bacteria, and wheezing during the first year of life. The effect of antibiotics was probably due to reverse causation. Since Clostridium was protective of wheezing, other anerobic bacteria are probably responsible for the increased risk of wheezing, which remains to be demonstrated.