Impact of nutritional status at the onset of elementary school on academic aptitude test achievement at the end of high school in a multicausal approach.

Like in many other countries, few investigations have been carried out in Chile to measure the long-term effects of nutritional status at an early age on scholastic achievement in a multicausal approach. The objectives of the present study were to describe the impact of nutritional, intellectual, family, educational and socio-economic variables at the onset of elementary school in 1987 that may affect achievement on the academic aptitude test (AAT) taken in 1998 at the end of high school, and to quantify the impact of these independent variables on the AAT. The present study comprises two cross-sectional stages: in 1987, a representative sample of 813 elementary school first-grader Chilean children from the Metropolitan Region was randomly chosen; in 1998, 12 years later, 632 school-age children were located and only 351 of them graduated from high school and, from these, 260 students took the AAT. In 1987 nutritional status was assessed through anthropometric parameters, intellectual ability by the Raven's Progressive Matrices Test, scholastic achievement through Spanish language and mathematics tests, and socio-economic status using Graffar's modified scale; family variables were also recorded. Maternal schooling, scholastic achievement, intellectual ability and head circumference-for-age z-score (anthropometric indicator of both nutritional background and brain development) all in 1987 were the independent variables with the greatest explanatory power for AAT variance in 1998 (r2 0.402). These results provide a foundation to identify the risk factors at an early age that affect AAT scores and should be useful to improve nutritional and educational policies.

Chilean school-age children twin registry: planning, sampling and implications.

We describe subject recruitment from the University of Chile School-Age Children Twin Registry (REMEUCHI). The research aim of REMEUCHI is to quantify the impact of genetic and environmental factors on scholastic achievement in a multicausal approach. The Ministry of Education of Chile, in collaboration with the Registry Office, provided the list of possible twin pairs graduated from high school in 2004 in Chile's metropolitan region. From a population of 70,065 school-age children who had graduated from high school, 434 possible twin pairs were analyzed. Of these, 327 were twins reared together (75.3% of the 434 possible twins pairs) and born between 1986 and 1987 in Chile (mean age 18 years), and approximately 8% were not twins despite matches on full name and birth data. The rest of the possible twin pairs were probably twins reared apart, since one member of the pair had moved to study in another region of Chile. Zygosity was determined through questionnaires, maternal reports of twin similarities, and by the hospital records of the twins at the time of birth. Three hundred and twenty-seven pairs were identified, where monozygotic (MZ) and dizygotic (DZ) twins represented 46.8% and 53.2% of pairs, respectively, with a DZ/MZ ratio of 1.14. Considering same-sex MZ pairs, the percentage of female pairs was greater (55.6%) than male pairs (44.4%). When DZ pairs were analyzed, 47.7% were of opposite sex, 20.1% were male pairs and 32.2% female pairs. In Chile, these findings represent a baseline study to contribute to the establishment of a national twin registry in the future.

Scholastic achievement: a multivariate analysis of nutritional, intellectual, socioeconomic, sociocultural, familial, and demographic variables in Chilean school-age children.

OBJECTIVE: We determined relative effects of nutritional status, intellectual ability, exposure to mass media, and socioeconomic, sociocultural, familial, demographic, and educational variables on scholastic achievement (SA). METHODS: This was a cross-sectional study. Exposure to mass media and nutritional, intellectual, socioeconomic, sociocultural, familial, demographic, and educational factors, including approximately 2000 variables, were measured in a representative and proportional sample of 4509 school-age children from elementary and high schools in Chile's Metropolitan Region. The field study was carried out between 1986 and 1987, and data processing, which lasted 15 y, was completed in 2002. RESULTS: Within the total sample, intellectual ability, level of maternal schooling, head circumference-for-age Z score, book reading, in-door plumbing, level of paternal schooling, type of school, quality of housing, height-for-age Z score, and calcium intake were the independent variables with the greatest explanatory power in SA variance (r(2) = 0.508). In most grades, IA was the independent variable with the greatest explanatory power in SA variance. In adolescents in their fourth year of high school and whose physical growth and intellectual development processes are consolidated, intellectual ability, age, head circumference-for-age Z score, book reading, type of school, and level of paternal schooling were the independent variables with the greatest explanatory power in SA variance (r(2) = 0.60). CONCLUSIONS: These findings show that SA is conditioned by multiple factors depending on the characteristics of school-age children, their families, and the educational system. Nutritional indicators of past nutrition are significantly associated with SA, especially head circumference-for-age Z score. This information may be useful for health and educational planning.

Head size and intelligence, learning, nutritional status and brain development. Head, IQ, learning, nutrition and brain.

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.

Nutritional status, brain development and scholastic achievement of Chilean high-school graduates from high and low intellectual quotient and socio-economic status.

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, high-school 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<00387) 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 (r2 0.707), without interaction with age, sex or SES. Child IQ (P<0.0001) was the only independent variable that explained both SA variance (r2 0.848) and academic aptitude test variance (r2 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.