Child development in a birth cohort: effect of child stimulation is stronger in less educated mothers.

Background: Child health has improved in many developing countries, bringing new challenges, including realization of the children's full physical and intellectual potential. This study explored child development within a birth cohort, its psychosocial determinants and interactions with maternal schooling and economic position.

Methods: All children born in Pelotas, Brazil, in 2004, were recruited to a birth cohort study. These children were assessed at birth and at 3, 12 and 24 months of age. In this last assessment involving 3869 children, detailed information on socio-economic and health characteristics was collected. Child development was assessed using the screening version of Battelle's Development Inventory. Five markers of cognitive stimulation and social interaction were recorded and summed to form a score ranging from 0-5. The outcomes studied were mean development score and low performance (less than 10th percentile of the sample).

Results: Child development was strongly associated with socio-economic position, maternal schooling and stimulation. Having been told a story and owning a book were the least frequent markers among children with score 1. These children were 8.3 times more likely to present low performance than those who scored 5. The effect of stimulation was much stronger among children from mothers with a low level of schooling--one additional point added 1.7 on the child's development for children of low-schooling mothers, whereas only 0.6 was added for children of high-schooling mothers.

Conclusions: Our stimulation markers cannot be directly translated into intervention strategies, but strongly suggest that suitably designed cognitive stimulation can have an important effect on children, especially those from mothers with low schooling.