Prevention of asthma

Abstract

Summary Several studies have documented an increasing prevalence of asthma and other allergic diseases in the last three decades both in industrialised and in developing countries. For this reason strategies for prevention are needed. In primary prevention, the preventive manoeuvres must be directed towards the whole population since the majority of atopic manifestations and of sensitisations occur in infants with no demonstrable risk at birth. Secondary prevention requires methods for detecting the population at risk with a large effort and investments for population screening. Tertiary prevention is the primary antinflammatory therapy in patients with allergic asthma. In all the stages of prevention allergen avoidance and reduction in exposure to adjuvant factor are foundamental. Food allergen avoidance does not seem to protect predisposed children from inhalant allergies later in childhood and children need to be protected not only from exposure to food antigens but strenuous efforts should be made to reduce house dust mite contact in the first year of life. The effect of other allergens besides mites is also extremely important. Since passive smoking is by far the best identified adjuvant risk factors for the development of allergic disease, particularly in early periods of life, it is obvious that avoidance of exposure to tobacco smoke is an important component of primary prevention of atopy. Furthermore the dietary regimen, advocated for the prevention of coronary heart diseases, with an increase in the intake of ω-6 polyunsaturated fatty acids such as linoleic acid, and a decrease in the intake of ω-3 saturated fatty acids, such as eicosapentaenoic acid, may have lead to an increase in allergic sensitisation. Therefore it is tempting to speculate that a diet rich in ω-3 fatty acid during pregnancy and during the first years of life may be associated with a preventive effect on the development of atopy. Early manipulation of the immune system towards the induction of a Th1 type response may be, in the near future, proposed in high risk infants.