Long-term effects of severe undernutrition during the first year of life on brain development and learning in Chilean high-school graduates

Abstract

The objective of this study was to assess the relative impact of undernutrition during the first year of life on brain development, intellectual quotient (IQ), and scholastic achievement (SA) of poor Chilean high-school graduates (mean age = 18.3 +/- 0.9 y). A comparative study of two groups of high-school graduates from a low socioeconomic stratum was carried out. The undernourished group (n = 16), who had suffered from severe undernutrition during the first year of life, was compared with the non-undernourished group (n = 16). The final sample consisted of 32 right-handed high-school graduate students born at term who had no history of alcoholism or symptoms of brain damage, epilepsy, or heart disease and whose mothers had no history of smoking, alcoholism, or drug intake before and during pregnancy. Socioeconomic status was measured by using Graffar's modified method. Birth weight was used as the prenatal nutritional status index, and postnatal nutritional status was assessed by the body mass index, Z score for head circumference, and brachial anthropometry. IQ was determined with the Wechsler Intelligence Scale for Adults, and SA was determined with test in language and mathematics with the academic aptitude test. Brain development was evaluated by magnetic resonance imaging. Statistical analysis included variance tests, Scheffe's test for comparison of means, correlation, and multiple regression. Maternal schooling, brain volume, and undernutrition were the independent variables, with the greatest explanatory power in IQ variance (r(2) = 0.714). Only IQ explained SA variance (r(2) = 0.860); IQ, corpus callosum length, anteroposterior diameter, and maternal schooling were the independent variables, with the greatest explanatory power in the academic aptitude test variance (r(2) = 0.949). Results show that the long-term effects of malnutrition at an early age may affect brain development, IQ, and SA in school-age children. These findings are useful for nutrition and educational planning.