primary prevention of coeliac disease - Associazione Italiana ...

50 INFANT FEEDING PRACTICES AND COELIAC DISEASE
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introduction of dietary gluten is of no importance with respect to coeliac disease risk .
In our case-referent study we could move one step further by also adjusting for the
differences in amount of gluten-containing foods given at various ages of introduction.
Our results also suggested that the age of the infant at introduction of dietary gluten was
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of no importance for coeliac disease risk , although with the limitation that only the
first year of life was evaluated.
Thus, present evidence does not support age of the infant at the time of gluten
introduction as an independent risk factor for coeliac disease development. However,
even when considered together these studies do not encompass all possible ages for
introduction of gluten, e.g. after one year of age or even later. Thus, this possibility also
needs to be evaluated.
Other possible contributing factors
Infections
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It has been proposed that adenovirus type 12 , and also other adenoviruses , could
initiate coeliac disease as a consequence of sequence similarities between a protein
produced in conjunction with the viral infection and A-gliadin. This has been
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questioned , but not convincingly excluded. Gastrointestinal infections cause a
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disruption of the barrier function of the small intestinal mucosa , which theoretically
could result in an increased antigen penetration and unfavourable immune responses.
We found a higher risk for coeliac disease in children born during summer as
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compared to winter, but only in children below two years of age . These findings
indicate that environmental exposure(s) with a seasonal pattern may have a causal
effect. A temporal relationship suggests that this might be due to a causal effect of
infections during foetal life and/or an interaction between infections and introduction
of gluten into the diet. However, any exposure with a seasonal pattern might be the
explanation, and non-infectious exposures should also be explored.
In our case-referent study we found that children who experienced three or more
infectious episodes before six months of age had an increased risk for coeliac disease
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before two years of age (adjusted OR=1.4, 95% CI 1.0-1.9) . This was true even when
episodes of gastroenteritis were excluded, and after adjustments were made for
differences in infant feeding patterns and family socio-economic group. Infectious
episodes later in infancy were not included, as these could be secondary to the disease
itself. The risk for coeliac disease increased considerably if in addition to having many
infections the child was also introduced to gluten in large amounts, as compared to
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small and medium amounts .
Socio-economic background
In our case-referent study children in families belonging to the lower as compared to
middle and upper socio-economic strata of Swedish society had an increased risk for
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coeliac disease (adjusted OR=1.4, 95% CI 1.0-1.8) , but again only in the age group
below two years. Our reported estimate was adjusted for differences in infant feeding
practices and infectious episodes. This indicates that there are also other as yet
unidentified environmental exposures contributing to the causal pattern of coeliac
disease.