Arctic Sneeze: Greenlanders’ allergies are increasing
During the past few decades, scientists have amassed evidence that allergic diseases are on the increase in the Western world. Bolstering these findings, a new study suggests that allergies in Greenland almost doubled from 1987 to 1998.
Allergic disorders such as asthma, hay fever, and eczema are common in wealthy nations. Research shows that up to 40 percent of children in some European and U.S. cities suffer from such afflictions.
Now, Danish epidemiologists led by Tyra Grove Krause at the Statens Serum Institut in Copenhagen have examined the prevalence of an allergy indicator in Greenland, a Danish territory populated mostly by Inuit. Since the 1950s, Greenlanders have increasingly given up hunting and fishing lifestyles and moved into towns and cities.
The researchers used frozen blood samples retained from syphilis- and HIV-screening campaigns in 1987 and 1998, respectively. They chose samples in each study from a wide cross section of 15- to 80-year-olds living in towns along Greenland’s rapidly industrializing western coast.
Krause and her team analyzed thawed samples–392 from the 1987 study and 467 from the 1998 study–for response of the antibody IgE against common allergens including pet fur, dust mites, mold, and several pollens. The IgE antibody serves as part of an allergic reaction.
The team found that the proportion of samples reacting to one or more allergens had jumped from 10 percent in 1987 to 19 percent in 1998. The largest increase in sensitivity to allergens occurred in samples taken from 15- to 19-year-olds.
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The findings, detailed in the Aug. 31 Lancet, add to mounting evidence that illnesses associated with Western nations, such as diabetes and heart disease, are on the rise in Greenland, says Krause.
The study documents “in a more robust manner what many other studies using more imperfect methods have implied,” that allergy is an increasing problem in the world, says David Corry at Baylor College of Medicine in Houston. “The $20 billion question of course is, Why?” he says.
Greenlanders are spending more time in modern carpeted homes, which are perfect traps for many sources of potential allergens, Corry suggests.
Another possible explanation is known as the hygiene hypothesis (SN: 8/14/99, p. 108: https://www.sciencenews.org/sn_arc99/8_14_99/bob2.htm). Graham A.W. Rook at the Royal Free and University College Medical School in London suggests that people in developed nations are exposed to fewer microorganisms than are people in developing nations with fewer resources for public hygiene and antibiotic treatments. Defending against parasites and bacteria at a young age may train the immune system. In an environment with fewer challenges from microorganisms, the immune system may learn to attack inappropriate targets, such as cat dander or pollen, he says.