Objective: The objective of this study is to evaluate the effect of risk factors on infant development, among low socioeconomic children born under optimal biological conditions, and who are exposed to adverse social circumstances.
Method: Infants of both sexes, in the amount of 788, were studied and controlled prospectively at between 6 and 12 months. Their mental (MDI) and psychomotor (PDI) development was evaluated using the Bayley Scale of Infant Development. Eighteen risk factors were identified and dichotomized (high or low risk).
Results: Breast feeding, child temperament, maternal intelligence and home stimulation are consistently associated with lower MDI and PDI. After adjustment for co-variables, home stimulation persisted as a significant factor for explaining the variation of both developmental indexes and child sex also appears as a risk factor for motor skills development. The accumulated effect of 7 or more risk factors is associated with a significant decrease of development scores. The combination of risk categories of child temperament, maternal IQ, paternal role and home stimulation shows higher prediction power for infant development than other combinations analyzed in this study.
Conclusion: The findings suggest than even for children born under optimal biological conditions their psychomotor development is negatively affected by the presence of simultaneous adverse environmental conditions.