The Urban-Rural Gradient In Asthma: A Population-Based Study in Northern Europe

Abstract

The early life environment appears to have a persistent impact on asthma risk. We hypothesize that environmental factors related to rural life mediate lower asthma prevalence in rural populations, and aimed to investigate an urban-rural gradient, assessed by place of upbringing, for asthma. The population-based Respiratory Health In Northern Europe (RHINE) study includes subjects from Denmark, Norway, Sweden, Iceland and Estonia born 1945–1973. The present analysis encompasses questionnaire data on 11,123 RHINE subjects. Six categories of place of upbringing were defined: farm with livestock, farm without livestock, village in rural area, small town, city suburb and inner city. The association of place of upbringing with asthma onset was analysed with Cox regression adjusted for relevant confounders. Subjects growing up on livestock farms had less asthma (8%) than subjects growing up in inner cities (11%) (hazard ratio 0.72 95% CI 0.57–0.91), and a significant urban-rural gradient was observed across six urbanisation levels (p = 0.02). An urban-rural gradient was only evident among women, smokers and for late-onset asthma. Analyses on wheeze and place of upbringing revealed similar results. In conclusion, this study suggests a protective effect of livestock farm upbringing on asthma development and an urban-rural gradient in a Northern European population.

Role and Frequency of Asthma Risk Factors in Triggering the Asthmatic Attack: A Cross-Sectional Study from Pakistan

“…The asthma is more common in boys than girls in childhood while the ratio of male and female is same around the age of 20 years and it is more common in females then males above the age of 40. [21] The results of this study were somewhat like the fact. 22% Females younger than the 15 years have asthma whereas the percentage of males was 24.4% whereas females are more affected by asthma in the older age 40+.…”

A clear urban–rural gradient of allergic rhinitis in a population-based study in Northern Europe

“…Furthermore, an urban–rural gradient has been suggested in the RHINE cohort for inflammatory bowel diseases (18) and asthma (19). …”

Do farm-grown lungs breathe better?

“…The ‘farm-effect’ documented in the present study may be a sustained effect from childhood onwards. Alternatively, it may be an effect on later-onset atopy or atopic asthma, as indicated by data from the RHINE study which includes part of the ECRHS study population 12. Arguably, a substantial portion of adult-onset or late-onset disease may be misclassified due to lack of recall of childhood disease in mid-adult ages.…”