Further Evidence Of Increase In Allergic Disease In Western Countries

Danish authors of a research letter in this week’s issue of THE LANCET provide further evidence which suggests that allergic diseases are becoming increasingly common in western populations.

Allergic diseases are thought to be increasingly common in more-developed countries, but few studies have measured the frequency of atopy with objective measures, and most of these studies have been done in industrialised countries. Tyra Krause and colleagues from Statens Serum Institut, Copenhagen, Denmark, analysed blood samples from around 850 15–80-year-old people in Greenland who had participated in screening programmes for sexually transmitted infections in 1987 and 1998.

Atopy was defined as a positive immune response to eight common inhalant allergens—grass, birch, mugwort, dog, cat, horse, the fungus Cladosporium herbarum, and house-dust mite. The frequency of atopy almost doubled between 1987 (10%) and 1998 (19%). This increase was largest in 15–19-year olds, but occurred in all age groups.

Tyra Krause COMMENTS: “We do not know what risk factors could have caused the increase in atopy, since Greenland has undergone a major transition from a traditional to a modern and westernised society over the recent decades. However, the fact that the increase in allergy has occurred in all age groups speaks against a general held belief that risk factors responsible for the epidemic increase in western countries only operate in childhood.