Obesity May Cancel Anti-Allergy Effects of Farm Childhood
Early exposure to microbes cuts allergy risks in the non-obese
WEDNESDAY, Dec. 27 (HealthDay News) -- Obesity may reduce the allergy-protective advantages of microbial exposure on farms in early childhood, researchers report in the December issue of the Journal of Allergy and Clinical Immunology.
Katja Radon, Ph.D., M.Sc., of the Institute for Occupational and Environmental Medicine in Munich, Germany, and a colleague studied allergies, body mass index and childhood farm contact in 1,861 obese and non-obese 18- to 45-year-olds. The goal was to assess the relationship between obesity, lower exposure to microbes characteristic of Western lifestyles, and allergy risks.
The researchers found that non-obese participants who spent their first three years on farms had a lower allergy risk (odds ratio, 0.6) than non-obese participants who had no early farm contact. But the same results did not hold for obese participants who had spent early years on farms (OR, 1.0) versus those without farm associations (OR, 1.2).
A similar pattern involved allergic rhinitis, the researchers report.
"Obesity, as a risk factor for respiratory allergies per se, might diminish or even cancel the protective effect of a farm childhood," the authors write, adding that obesity could also explain "the high prevalence of respiratory allergies in inner-city societies despite lower levels of hygiene."