RT Journal Article
SR Electronic
T1 The â'farm-effect' on the age of onset of asthma through childhood into adolescence - A prospective cohort study
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP P1554
VO 42
IS Suppl 57
A1 Jon Genuneit
YR 2013
UL http://erj.ersjournals.com/content/42/Suppl_57/P1554.abstract
AB Background: Many cross-sectional studies have documented the protective ‘farm-effect’ on childhood asthma investigating cumulative incidence of disease among children within a wide age range.Aims: This study investigated the ‘farm-effect’ on asthma by age of onset to determine whether it is acting at all ages in childhood.Methods: A prospective cohort study was conducted around Ulm, southern Germany, with baseline assessment among 6-10 year-olds in 2006 as part of the GABRIELA study. Data from baseline (n=2248) and yearly follow-ups in 2010-2012 (92% completed at least one follow-up) are reported. Subjects who indicated an asthma diagnosis before the age of 5 were excluded. Farm children were living on a farm run by the family; exposed non-farm children were regularly exposed to farm life; the rest were the unexposed reference. We modeled stratified weighted cox regression adjusting for potential confounders.Results: Overall, 129 (7.5%) children had a diagnosis of asthma. The ‘farm-effect’ was seen with constant protection across all ages of onset. The adjusted hazard ratio (95%CI) for asthma was 0.54 (0.32;0.91) for farm children vs. the unexposed reference. For exposed non-farm children vs. the reference it was 1.06 (0.69;1.64). Interestingly, the cumulative incidence of asthma became higher for girls than for boys around onset of puberty only among the unexposed reference. This held true after dichotomising the exposure into living on a farm at baseline.Conclusion: The ‘farm-effect’ persists throughout childhood into adolescence. The gender-switch in asthma risk around puberty may be delayed or abolished among subjects exposed to farming environments.