For decades, allergic diseases have been recognised to be infrequent among Africans. But almost all of the black, Xhosa participants in this South African study had increased IgE levels – the type of antibody most instrumental in allergic reactions.
As a higher degree of sensitisation to allergens is related to increased asthma incidence, it's worth taking note of these statistics.
IgE levels 15 times higher
According to Dr Mike Levin, study leader and paediatrician from Cape Town, the research among 225 Xhosa children revealed that the mean IgE levels were 15 times higher in the black children than the mean IgE levels for the Caucasian population.
The study also showed that 9% of the study participants had a history of asthma, 16% had increased bronchial hyper-reactivity (or "twitchy airways") and 33% reacted to skin prick tests.
Levin believes that the Xhosa population may be genetically predisposed to allergies and asthma, but that, up until recently, the environment hasn't been conducive. Current exposure to foreign allergens from the newly adopted Western lifestyle may now be contributing to the problem.
Cause of asthma remains unknown
The exact cause of asthma remains one of the biggest mysteries in modern medicine. Ten years ago, scientists believed that diesel exhaust and other pollutants might be at the root of the problem. They now know that the picture is more complex. Countries where the prevalence of asthma is high, like the United Kingdom and the United States, have relatively clean air.
Asthma attacks can be triggered by allergens (e.g. house dust mites, grass, tree pollens, cat dander), certain environmental factors (e.g. air pollutants, cigarette smoke, exhaust fumes) and exposure to harmful substances in the workplace (e.g. organic dust, isocyanates, formaldehyde, exopy resin).
South Africa has the world's fifth highest death rate from asthma even though effective therapy is freely available. Experts reckon that problems with treatment availability, access to emergency services and lack of knowledge are contributing to the high death rate.
"We need to jack up our provision of drugs and our basic access to healthcare treatment to combat this problem," Levin says.