[Allergen sensitization and asthma in children from 1 to 3 years of age].

BACKGROUND

Asthma is a multifactorial disease. Children with atopy history could be sensitized with indoor and food allergens from early stages of the life and this predispose to develop asthma. Controversy exists about the factors that increase or decrease the risk of disease, such as breast feeding, early weaning, smoking exposition, immunizations.

OBJECTIVE

To determine if these risk factors and inhaled and food allergen sensitization predispose to asthma development.

METHODS

A case-control study was performed. Cases (1 to 3 year-old 74 children) with asthma and control (74 healthy age-matched children) were included, r2 = 0.90. Skin-prick test (SPT) was performed by using indoor and food allergens. Test was considered positive if skin reaction was equal or higher than 3 mm. The results were compared by means of the x2 test. A logistic regression analysis was performed for obtaining odds ratio (OR) (95% confidence interval for each factor).

RESULTS

Out of the SPT carried out with aero-allergens, 23 (31%) were positive in the two groups. Regarding the food, 27 cases (36.4%) and 15 controls (20.2%) were positive (x2 = 4.7); p < 0.05, OR = 2.2, IC 95% (1.6-3.1). Atopy was positive in 50 (67.5%) cases and 39 (52.7%) of the controls (x2 = 3.4); p < 0.05, OR 1.8 (1.3 to 2.5). The weaning before the first three months of life was positive in 44 (59.4%) of the cases against 15 (20.2%) of the controls (x2 = 23.7) p < 0.05 with a OR 5.7 (4.9 at 6.6).

CONCLUSIONS

We found a probability 2.2 times higher for developing asthma when children were sensitive to at least one food. We also reported that 100% of our sensitized cases with food had received breast feeding during the first four months of life, which is similar to results of other authors where the breast feeding during an intermediate time (one to six months) does not protect against allergic disease. Early introduction of solid food (before the three months of age) was the main factor increasing probability for developing asthma. In our study, atopy almost duplicated this probability.