Obviously, a long list of lifestyle-related factors possibly associated with the apparent allergy and asthma epidemic of the late twentieth and early twenty-first centuries may have relevance to the atopic march in children.
Taking into account that the risk of atopic sensitization and disease manifestation early in life is particularly high in industrialized Western countries, and that within these countries concomitant variations in the socioeconomic status and the prevalence of atopy are evident, the question arises as to what factor related to Western lifestyle may be responsible for increasing the susceptibility to atopic sensitization?
In a recent Swedish study, the prevalence of atopy in children from anthroposophic families was lower than in children from other types of families.
This led the authors to the conclusion that lifestyle factors associated with anthroposophy
(no vaccination, low exposure to antibodies, etc.) may lessen the risk of
atopy in childhood.
Several studies focusing on differences between the former socialist countries and Western European countries reported lower prevalence rates for atopy in the former East.
The differences were particularly striking in the areas with few genetic differences such as East and West Germany where it was found that the critical period during which lifestyle mainly influences the development of atopy is probably the first years of life. These observations point in the same direction as studies reporting lower prevalence rates for children born into families that have few siblings. Recent observations from Germany suggest that within the population of
an industrialized country with a Western lifestyle, high socioeconomic status must be considered as a risk factor for early sensitization and the manifestations of atopic dermatitis and allergic airway disease. Turkish migrants living in Germany exhibited higher prevalences of atopy and asthma after cultural assimilation. Differences in the intestinal microflora as a major source of microbial stimulation of the immune system in early childhood has been proposed as a possible explanation for this observation. The intestinal microflora have been shown to enhance Th1-type responses. The results of a comparative study of Estonian and Swedish children demonstrated differences in intestinal microflora. In Estonia, the typical microflora included more lactobacilli and fewer clostridia organisms that are associated with a lower presence of atopic disease. Intervention studies are needed to demonstrate the relevance of these findings and examine the effects of adding probiotics to infant formulas. In one study from Finland, which unfortunately
was not blinded, infants with milk allergy and atopic dermatitis exhibited milder symptoms and fewer markers of intestinal inflammation if they were fed lactobacilli-fortified milk formula.
Few reports have described an association between the use of antibiotics during the first 2 years of life and increased risks of asthma. It seems too early to draw final conclusions from these publications.
Immunizations against infectious diseases do not appear to influence the risk of early sensitization or development of atopy. Physicians should therefore support successful immunization programs such as those targeting measles.