The Effect of Early Food Introduction and Skin Emollients on Pollen Sensitization: A Randomized Trial (PreventADALL) Sub-Study.

BACKGROUND

Pollen sensitization may be directed toward proteins also found in plant foods.

OBJECTIVE

We explored whether early food introduction and skin emollients prevented birch and grass sensitization at age 3 years and whether the effect was mediated by skin barrier function or modified by season of birth.

METHODS

In the population-based, randomized, controlled Preventing Atopic Dermatitis and Allergy in Children trial, information on allergic sensitization by age 3 years was available in 2,066 children. Newborns were randomized (1:1:1:1) to no (controls); to food (tastes of peanut, cow's milk, wheat, and egg from 3 months) or skin (oil baths and facial cream from 2 weeks); or to both interventions. Sensitization was defined as specific IgE 0.1 kUA/L or greater and/or skin prick test wheal 3 mm or greater. A mediator analysis assessed the skin intervention's effect through transepidermal water loss at 3 months. An interaction analysis estimated effect modification by month of birth.

RESULTS

At age 3 years, 117 of 1,492 children (7.8%) were sensitized to birch and 40 of 1,482 children (2.7%) to timothy. Compared with controls, crude odds ratio (95% CI) in the food, skin, and combined intervention groups, respectively, was 1.10 (0.63-1.93), 2.38 (1.43-3.95), and 0.70 (0.37-1.34) for birch, and 0.58 (0.21-1.60), 1.73 (0.77-3.91), and 1.00 (0.40-2.49) for grass sensitization. A significant indirect effect of the skin intervention through transepidermal water loss was observed, but there was no significant modification by month of birth for either intervention.

CONCLUSIONS

Early food introduction did not affect the risk of pollen sensitization. Infants with skin intervention had increased risk only of birch sensitization, mediated by reduced skin barrier function in early infancy.