Posted on Feb 26, 2013, 6 a.m.
People who live close to the equator may be at higher risk for allergies and asthma.
Worldwide variations in allergy prevalence suggest that geographic factors may contribute to asthma. Previous ecologic studies have suggested that latitude, a marker of UV-B exposure and allergen exposures, may be related to clinical allergies. Vicka Oktaria, from the University of Melbourne (Australia), and colleagues analyzed data collected in the Tasmanian Longitudinal Health Study, a population-based study of respiratory disease spanning childhood to adulthood with a most recent follow-up including a postal survey of 5,729 participants and a clinical substudy of 1,396 participants. The team observed that those living near the equator are at an increased risk of developing allergy and asthma. Positing that because UV-B ray exposure is higher for people living in areas closer to the equator, this increase may be linked to vitamin D, which is thought to modify the immune system – these modifications could lead to elevated risk of developing allergy risk.
Vicka Oktaria, Shyamali C. Dharmage, John A. Burgess, Julie A. Simpson, Stephen Morrison, Graham G. Giles, et al. “Association between latitude and allergic diseases: a longitudinal study from childhood to middle-age.” Annals of Allergy, Asthma & Immunology, Volume 110, Issue 2, February 2013, Pages 80-85.e1