Late Breaking Abstract - Childhood farming environment: Association to age at asthma diagnosis in a population-based study

Abstract

Background: Association of childhood farming environment to late-diagnosed asthma is poorly understood. Most studies are based on a population <50 years of age. The childhood farming environment and its microbiota reduce the likelihood of allergic asthma.

Objective: Driving immunity differ in early- and late-diagnosed asthma. Therefore, we hypothesized that the childhood environment might modify asthma risk differently for early-onset and late-onset asthma.

Methods: A cross-sectional population-based study was performed on subjects aged 20-69 years in Western Finland. The response rate was 52.5% and for those over 60 years 73.8%. We included 3864 participants, of whom 426 had physician-diagnosed asthma with a known age at diagnosis. Population was 3864 in early-diagnosed (0-11 years), 2832 in intermediate-diagnosed (12-39 years), and 1380 in late-diagnosed (40-69 years) in adjusted logistic regression analyses. To minimize bias, we used population aged 40-69 for intermediate-diagnosed and 60-69 years for late-diagnosed asthma analysis.

Results: Childhood farming environment increased the odds of late-diagnosed asthma (aOR, 2.30; 95% CI, 1.12-4.69), but the odds were lower for early- (aOR, 0.49; 95% CI, 0.30-0.80) and intermediate-diagnosed asthma (aOR, 0.75; 95% CI, 0.47-1.18). The results remained after the exclusion of current and former farmers or co-existing COPD. The main result was validated in another cohort from Finland.

Conclusions: Childhood farming environment was associated with higher odds for late-diagnosed asthma.