This multifactorial study investigates the interrelationships between head circumference (HC) and intellectual quotient (IQ), learning, nutritional status and brain development in Chilean school-age children graduating from high school, of both sexes and with high and low IQ and socio-economic strata (SES). The sample consisted of 96 right-handed healthy students (mean age 18.0 +/- 0.9 years) born at term. HC was measured both in the children and their parents and was expressed as Z-score (Z-HC). In children, IQ was determined by means of the Wechsler Intelligence Scale for Adults-Revised (WAIS-R), scholastic achievement (SA) through the standard Spanish language and mathematics tests and the academic aptitude test (AAT) score, nutritional status was assessed through anthropometric indicators, brain development was determined by magnetic resonance imaging (MRI) and SES applying the Graffar modified method. Results showed that microcephalic children (Z-HC < or = 2 S.D.) had significantly lower values mainly for brain volume (BV), parental Z-HC, IQ, SA, AAT, birth length (BL) and a significantly higher incidence of undernutrition in the first year of life compared with their macrocephalic peers (Z-HC > 2S.D.). Multiple regression analysis revealed that BV, parental Z-HC and BL were the independent variables with the greatest explanatory power for child's Z-HC variance (r(2) = 0.727). These findings confirm the hypothesis formulated in this study: (1) independently of age, sex and SES, brain parameters, parental HC and prenatal nutritional indicators are the most important independent variables that determine HC and (2) microcephalic children present multiple disorders not only related to BV but also to IQ, SA and nutritional background.

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The objective of the present study was to investigate the inter-relationships between nutritional status (past and current nutrition), brain development, and scholastic achievement (SA) of Chilean high-school graduates from high and low intellectual quotient (IQ) and socio-economic status (SES) (mean age 18 : 0 (SD 0 : 9) years). Results showed that independently of SES, highschool graduates with similar IQ have similar nutritional, brain development and SA variables. Multiple regression analysis between child IQ (dependent variable) and age, sex, SES, brain volume (BV), undernutrition during the first year of life, paternal and maternal IQ (independent variables) revealed that maternal IQ (P,0 : 0001), BV (P,0 : 0387) and severe undernutrition during the first year of life (P,0 : 0486), were the independent variables with the greatest explanatory power for child IQ variance (r 2 0 : 707), without interaction with age, sex or SES. Child IQ (P,0 : 0001) was the only independent variable that explained both SA variance (r 2 0 : 848) and academic aptitude test variance (r 2 0 : 876) without interaction with age, sex or SES. These results confirm the hypotheses formulated for this study that: (1) independently of SES, high-school graduates with similar IQ have similar variables of nutritional status, brain development and SA; (2) past nutritional status, brain development, child IQ and SA are strongly and significantly inter-related. These findings are relevant in explaining the complex interactions between variables that affect IQ and SA and can be useful for nutritional and educational planning.

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Objective: To determine the impact of nutritional status in a multicausal approach of socio-economic, socio-cultural, family, intellectual, educational and demographic variables at the onset of elementary school in 1987 on the educational situation of these children in 1998, when they should have graduated from high school. Setting: Chile's Metropolitan Region. Design: Prospective, observational and 12-year follow-up study. Methods: A representative sample of 813 elementary first grade school-age children was randomly chosen in 1987. The sample was assessed in two cross-sectional studies. The first cross-sectional study was carried out in at the onset of elementary school in 1987 and the second was carried out in 1998, 12-years later, when they should be graduating from high school. In 1998, 632 adolescent students were located and their educational situation was registered (dropout, delayed, graduated and not located). At the onset of elementary school were determined the nutritional status, socio-economic status (SES), family characteristics, intellectual ability (IA), scholastic achievement (SA) and demographic variables. Statistical analysis included variance tests and Scheffe's test was used for comparison of means. Pearson correlation coefficients and logistic regression were used to establish the most important independent variables at the onset of elementary school in 1987 that affect the educational situation 1998. Data were analysed using the statistical analysis system (SAS). Results: Logistic regression revealed that SES, IA, SA and head circumference-for-age Z score at the onset of elementary school in 1987 were the independent variables with the greatest explanatory power in the educational situation of school-age children in 1998. Conclusions: These parameters at an early school age are good predictors of the educational situation later and these results can be useful for nutrition and educational planning in early childhood.