Urban vs rural residency and allergy prevalence among adult women: Iowa Women's Health Study

Ann Allergy Asthma Immunol. 2018 Jun;120(6):654-660.e1. doi: 10.1016/j.anai.2018.03.029. Epub 2018 Apr 6.

Abstract

Background: The association between residence and allergy has been well studied in children living on a farm; however, studies of this association in late adulthood are lacking.

Objective: This study examined the association between residence and allergy in 25,393 women aged 55–69 years in the large prospective Iowa Women’s Health Study (IWHS).

Methods: IWHS questionnaires collected information on socio-demographic and anthropometric characteristics, medical history, lifestyle behaviors, dietary intake, residence and allergy. Residence reported at baseline (1986) was categorized into 5 groups based on living on a farm, rural, or urban areas and population size. Allergy was determined from four self-reported questions about physician-diagnosed asthma, hay fever, skin allergy, and other allergy. Logistic regression was used to determine significant risk factors for allergy and prevalence odds ratios (OR) and 95% confidence intervals (CI) for allergy associated with residence.

Results: Compared to large city of >10,000 residents, those living on farm, rural and smaller urban areas had decreased odds ratios of overall, skin, and other allergy in age and multivariable-adjusted models. The multivariable ORs (95% CI) for farm versus large city were decreased for overall allergy: 0.72 (0.66, 0.78) and all allergy types including asthma: 0.87 (0.75, 1.00), hay fever: 0.77 (0.69, 0.88), skin: 0.76 (0.68, 0.86), and other allergy: 0.76 (0.68, 0.86).

Conclusion: This study supports a hypothesis that farm living is inversely associated with allergy, suggesting that environmental exposures may protect against allergy not only in childhood, but also in late adulthood.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Asthma / epidemiology*
  • Asthma / physiopathology
  • Cross-Sectional Studies
  • Eczema / epidemiology*
  • Eczema / physiopathology
  • Female
  • Humans
  • Iowa / epidemiology
  • Middle Aged
  • Prevalence
  • Rhinitis, Allergic, Seasonal / epidemiology*
  • Rhinitis, Allergic, Seasonal / physiopathology
  • Rural Population
  • Surveys and Questionnaires
  • Urban Population
  • Women's Health / statistics & numerical data