Nearly one in three Europeans suffers - or will suffer - from an allergy. 10% of children suffer from asthma. Described by some scientists as 'the real millennium bug', allergies have become progressively more common over the past two decades. And the social cost - in terms of health care and absenteeism, for example - is estimated at 45 billion euros a year. A major research effort is essential in this field where our knowledge shows some surprising gaps.
First described by the Austrian physician Clemens von Picquet back in 1906, an allergy is an 'inflammation' which follows exposure to a specific substance or micro-organism, known as an allergen. The body responds to a usually inoffensive stimulus by triggering the action of immune mechanisms - just as it does when defending us against germs, but in this case for no real purpose. The body's reaction is violent and, in the extreme and rare cases of anaphylactic shock, can even prove fatal.
'There are many different types of cause,' explains Dr Alain Vanvossel, a scientific officer at the Research DG. 'Genetic factors and immunological aspects can all play a part, as well as pollution and other environmental factors, as can lifestyle, including diet. So all these avenues must be explored if we want to make any progress in preventing allergies.'
Allergies are made all the more complex by the fact that they are often triggered by a combination of factors which are difficult to identify. Their incidence can vary in the course of a lifetime and the phenomenon of crossed reactivity further complicates an already difficult diagnosis.
Increase in asthma
Respiratory allergies are among the most common. They include allergic rhinitis, such as the familiar hay fever, the incidence of which seems to have increased from 1% of the population at the beginning of the 20th century to between 15% and 20% over recent years, affecting adolescents and young adults in particular. 'This complaint should not be viewed as a minor irritation,' states the European Allergy White Paper. (1) 'Recent studies show that chronic allergic rhinitis, usually caused by the allergens found in buildings, cause a level of discomfort in the patient equivalent to that of moderate asthma. Some studies even suggest that this complaint can lead to asthma.'
The link is worrying, as asthma is another major allergy. It affects 10% of children, continues in 5% of adults and affects twice as many people as 20 years ago. Polluted air - with NOx from vehicle emissions, for example - is increasingly being cited as the cause of the problem and some statistics show that asthma is more common in urban than rural areas. Socio-economic factors are also mentioned, as asthma is more frequent among the socially disadvantaged. Although the resulting mortality is low in Europe, the number of children who suffer from it is a cause for concern, as is the number of determining factors which remain unidentified and which are probably linked to the interaction between our genes and lifestyle.
Skin allergies are another major category of allergy. A number of studies have found a worrying increase in atopic dermatitis over recent decades. Also linked to hereditary factors, in some regions of Europe as much as a quarter of the population is believed to be affected by this condition. Eczema and urticaria are also affecting a growing number of people, with experts predicting that between 40% and 60% of them are at risk of going on to develop respiratory problems.
Diet is very often seen as being responsible for these disorders. Here it is more a question of intolerance than of allergies proper as the symptoms are not due to an activation of the immune mechanism. But whatever the case, this hypersensitivity is also linked to a change in lifestyle.
'Europe is certainly not without its strengths in conducting the research required to combat this public health problem,' believes Dr Vanvossel. 'In addition to multidisciplinary teams of high-level scientists, it also has the diversity of populations, lifestyles, environments and public-health systems to permit a very targeted approach.'
The Quality of life and management of human resources programme under the Fifth Framework Programme for Research is already supporting studies by over 50 European teams, many of them also cooperating with laboratories in EU-applicant countries (see examples below). Some are concerned specifically with asthma and the aetiology of allergies, some with food allergens, and some with methods of diagnosis and treatment strategies. 'The emphasis is clearly on prevention. That is why it is important to ensure that the results get back to the people in question, and that they are put to the best possible use, as it is often issues of lifestyle which are raised by these diseases,' concludes Dr Vanvossel. Further calls for proposals for research on allergies are planned for March 2001 and 2002 under the Quality of life programme. These will make it possible to finance a large number of innovative projects in this field.
(1) European Allergy White Paper - Allergic diseases as a public health problem in Europe, The UCB Institute of Allergy, 1997
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