Fig. 1

Proposed theoretical model, Ribeirão Preto-SP, 2010–2013. Mother’s skin color was the most distal variable with an effect on socioeconomic status (SES), which is directly associated with the other variables of the model. Family allergy directly affects allergy traits around the 2nd year of life and is affected by the mother’s age and pregestational body mass index – BMI. Prenatal factors (pregestational BMI, smoking during pregnancy, gestational diabetes and hypertension during pregnancy) are intrinsically related to a positive effect on allergy traits [10, 18]. Prenatal factors would affect gestational age, type of delivery, overweight at birth and Apgar score, which would be directly related to allergy traits [8, 13]. Exclusive breast feeding would be a protective factor for allergic diseases