Data collection consisted of physical evaluation and application of a questionnaire to parents to gather birth data, health conditions, age enrollment in day care, and maternal education. For assessment of the family's socioeconomic status, the ABEP questionnaire (Associação Brasileira de Empresas de Pesquisa/Brazilian Market Research Association) was used for economic classification.30 The questionnaire uses characteristics of the home (number of TV, radio, bathroom, car, housemaid, washing machine, DVD, refrigerator, freezer, and education level of the head of the household) to quantify the socioeconomic level at A, B, C, D or E.30