Background and objective: Recent investigations have focused on the role of infections in infancy in promoting or protecting against the subsequent development of asthma. A related hypothesis concerns the possible role of medical responses to infections, including the widespread use of antibiotics. We chose children at Rudolf Steiner schools to test this latter hypothesis because a significant proportion of parents rejects the use of conventional treatments, including antibiotics.
Methods: Seventy-five per cent (n = 456) of parents of children aged 5-10 years attending Rudolf Steiner schools throughout New Zealand completed questionnaires which included questions on the use of antibiotics and a history of asthma and wheeze in their children.
Results: After controlling for potential confounders, antibiotic use was significantly associated with having a history of asthma (OR = 2.74, 95% CI: 1.10-6.85) or wheeze (OR = 1. 86, 95% CI: 1.06-3.26) but not with current wheeze (OR = 1.08, 95% CI: 0.54-2-16). The adjusted odds ratio for asthma was 4.05 (95% CI: 1.55-10.59) if antibiotics were used in the first year of life and 1. 64 (95% CI: 0.60-4.46) if antibiotics had been used only after the first year of life when compared with children who had never used antibiotics. The number of courses of antibiotics during the first year of life was also associated with increased odds ratios for asthma: 2.27 (95% CI: 1.14-4.51) for one to two courses and 4.02 (95% CI: 1.57-10.31) for three or more courses when compared with no antibiotic use in the first year of life. Although not significant, the association of antibiotics and hay fever (OR = 1.99 [95% CI: 0. 93-4.26]) was of a similar strength to the association of antibiotics with a history of wheeze. Antibiotics were not significantly associated with eczema (OR = 1.23 [95% CI: 0.71-2.13]).
Conclusion: Antibiotic use in infancy may be associated with an increased risk of developing asthma. Further study is required to determine the reasons for this association.