Early-life adversity is associated with poor iron status in infancy.

Exposure to early-life adversity (ELA) and iron deficiency early in life are known risk factors for suboptimal brain and socioemotional development. Iron deficiency may arise from and co-occur with ELA, which could negatively affect development. In the present study, we investigated whether ELA is associated with iron deficiency in infants receiving no iron supplementation. This study is a secondary analysis of extant data collected in the 1990s; participants were healthy infants from working-class communities in Santiago, Chile (N = 534, 45.5% female). We measured stressful life events, maternal depression, and low home support for child development during infancy and assessed iron status when the infant was 12 months old. Slightly more than half of the infants were iron-deficient (51%), and 25.8% were iron-deficient anemic at 12 months. Results indicated that ELA was associated with lower iron levels and iron deficiency at 12 months. The findings are consistent with animal and human prenatal models of stress and iron status and provide evidence of the association between postnatal ELA and iron status in humans. The findings also highlight a nutritional pathway by which ELA may impact development and present a nutritionally-focused avenue for future research on ELA and psychopathology.

Sociodemographic predictors of early postnatal growth: evidence from a Chilean infancy cohort.

OBJECTIVES: Infant anthropometric growth varies across socioeconomic factors, including maternal education and income, and may serve as an indicator of environmental influences in early life with long-term health consequences. Previous research has identified sociodemographic gradients in growth with a focus on the first year and beyond, but estimates are sparse for growth before 6 months. Thus, our objective was to examine the relationship between sociodemographic factors and infant growth patterns between birth and 5 months of age. DESIGN: Prospective cohort study. SETTINGS: Low-income to middle-income neighbourhoods in Santiago, Chile (1991-1996). PARTICIPANTS: 1412 participants from a randomised iron-deficiency anaemia preventive trial in healthy infants. MAIN OUTCOME MEASURES: Longitudinal anthropometrics including monthly weight (kg), length (cm) and weight-for-length (WFL) values. For each measure, we estimated three individual-level growth parameters (size, timing and velocity) from SuperImposition by Translation and Rotation models. Size and timing changes represent vertical and horizontal growth curve shifts, respectively, and velocity change represents growth rate shifts. We estimated the linear association between growth parameters and gestational age, maternal age, education and socioeconomic position (SEP). RESULTS: Lower SEP was associated with a slower linear (length) velocity growth parameter (-0.22, 95% CI -0.31 to -0.13)-outcome units are per cent change in velocity from the average growth curve. Lower SEP was associated with later WFL growth timing as demonstrated through the tempo growth parameter for females (0.25, 95% CI 0.05 to 0.42)-outcome units are shifts in days from the average growth curve. We found no evidence of associations between SEP and the weight size, timing or velocity growth rate parameters. CONCLUSION: Previous research on growth in older infants and children shows associations between lower SEP with slower length velocity. We found evidence supporting this association in the first 5 months of life, which may inform age-specific prevention efforts aimed at infant length growth.

Serum Polyunsaturated Fatty Acids in Middle Childhood and Body Mass Index Change Through Adolescence.

BACKGROUND: Polyunsaturated fatty acids (PUFA) status in childhood may be associated with adiposity development. OBJECTIVE: To assess associations of serum PUFA biomarkers in childhood with change in body mass index (BMI)-for-age Z scores (BMIZ) through adolescence. METHODS: We quantified serum PUFA at ages 5 and 10 years among 418 children from Santiago, Chile. BMI was measured at 5, 10, and 16 years. We compared BMIZ change through age 16 years between quartiles of PUFA at 5 and 10 years and PUFA change 5-10 years by fitting growth curves from mixed effects models. RESULTS: At age 5 years, serum docosahexaenoic acid was inversely associated with BMIZ change from ages 5 to 16 years. At age 10 years, arachidonic acid (AA) was nonlinearly positively related to BMIZ change from ages 10 to 16 years. Change in AA and the Δ5-desaturase (D5D) activity index between 5 and 10 years were each positively associated with BMIZ change from ages 10 to 16 years. Change in eicosapentaenoic acid was inversely associated with change in BMIZ. CONCLUSIONS: Serum long-chain n-3 PUFA in middle childhood were associated with less BMI gain through adolescence, whereas AA and D5D activity was related to greater BMI gain.

Brain development and scholastic achievement in the Education Quality Measurement System tests in Chilean school-aged children.

BACKGROUND: Head circumference (HC), the anthropometric index of both brain development and nutritional background, has been described to be significantly associated with scholastic achievement (SA). The aim of this study was to determine the impact of nutritional background and current nutritional status parameters on SA in the Education Quality Measurement System (SIMCE) tests. METHODS: A representative sample of 33 schools was randomly chosen in the Metropolitan Region of Chile. The sample consisted of 1,353 school-aged children of both sexes, from the fifth grade of elementary school and from the first grade of high school who in 2009 took the SIMCE tests. Nutritional status was assessed through anthropometric parameters. Brain development was measured through the HC expressed as HC-for-age Z-score (Z-HC). RESULTS: Students with Z-HC < -2 SD and >2 SD obtained low and high SA, respectively, both in the language and the mathematics tests (P < 0.001). In general, in both grades, those students with Z-HC ≥ 0 SD increase more than double the probability to obtain language and mathematics SA scores ≥ the median (P < 0.0001). CONCLUSION: We confirm the hypothesis that HC is the most relevant physical index associated with SA; therefore, children with the lowest scores in the SIMCE tests probably have lower brain development.

Somatotype and intellectual ability (Raven Progressive Matrices Test) in Chilean school-age children.

OBJECTIVES: The aim of this study was to determine the relationship between somatotype and intellectual ability (IA) in 11-12 and 15-16 year-old students (n = 1,015) in the Chile's Metropolitan Region from a representative sample of 33 educational establishments chosen at random. METHODS: The Heath-Carter somatotype and the IA assessed through the Raven Progressive Matrices Test were measured. RESULTS: The endomorph was observed in 59% of the students; 28% had a mesomorph and 13% ectomorph. The IA was distributed in: 11.2% Grade I, 26.8% Grade II, 41% Grade III, 17.6% Grade IV and 3.2% Grade V. A positive and significant correlation of IA with the endomorphic component (r = 0.074, p = 0.02) was found in the total sample and only in females (r = 0.109, p = 0.02); at the same time, a positive and significant correlation with the ectomorph component was also observed (r = 0.067, p < 0.05). CONCLUSIONS: This suggests that other variables would influence more strongly the IA for which further research is needed to quantitate this multifactorial problem.

Objetivos: El objetivo de este estudio fue determinar la relación entre el somatotipo y la habilidad intelectual (HA) en estudiantes de 11-12 y 15-16 años de edad de la Región Metropolitana, Chile. Métodos: Se registró una muestra representativa de 1.015 escolares de acuerdo a los resultados del sistema de medición de la calidad de la educación (SIMCE) 2009. Se evaluó el somatotipo de Heath-Carter y la HA de acuerdo al Test de Matrices Progresivas de Raven. Resultados: Un 59% presentó un somatotipo endomórfico, 28% mesomórfico y 13% ectomorfo. La HA se distribuyó en: 11,2% Grado I, 26,8% Grado II, 41% Grado III, 17,6% Grado IV y 3,2% Grado V. Se presenta una correlación significativa positiva con el componente endomórfico (r = 0,074 p = 0,02), y sólo en mujeres (r = 0,109 p = 0,02), a la vez se observa una relación significativa positiva con el componente ectomorfo (r = 0,067 p < 0,05). Conclusiones: Esto sugiere que otras variables estarían influyendo más fuertemente en la HA, además de apoyar la no discriminación por biotipo en los establecimientos educacionales.

High HOMA-IR, adjusted for puberty, relates to the metabolic syndrome in overweight and obese Chilean youths.

OBJECTIVE: To determine how the homeostasis model assessment of insulin resistance (HOMA-IR) is related to metabolic risk in a sample of overweight and obese Chilean youths accounting for Tanner stage. METHODS: A cross-sectional study assessing 486 overweight and obese youths (aged 5-15 years) recruited from the University of Chile, Pediatric Obesity Clinic. We measured anthropometry, Tanner stage, HOMA-IR, and laboratory tests related to metabolic risk. HOMA-IR was categorized by quartile for children (Tanner stages I and II) and adolescents (Tanner stage III and above) from a normative Chilean sample. RESULTS: Children and adolescents with HOMA-IR in the highest quartile were likely to have higher body mass index (BMI) Z-scores, elevated waist circumference, systolic and diastolic blood pressure, and triglycerides and low high-density lipoprotein. HOMA-IR had good negative predictive value for characteristics of the metabolic syndrome (MetS; 0.82). In a multivariate regression model, BMI Z-score [odds ratio (OR) 1.5] and HOMA-IR (OR 3.3) predicted 22% of the variance for the MetS, with 36% of the explained variance attributed to HOMA-IR. CONCLUSIONS: In a large clinical sample of overweight and obese Chilean youths, HOMA-IR ≥ 75th percentile was significantly associated with the cluster of factors referred to as the MetS. We emphasize the importance of establishing percentiles for HOMA-IR based on a normative sample and taking Tanner stage into account. Although BMI is easy to assess and interpret with minimal costs in a clinical setting, adding HOMA-IR explains more of the variance in the MetS than BMI Z-score alone.

[Variations of body mass index (BMI) according to degree of pubertal development]. / Variaciones del indice de masa corporal (IMC) de acuerdo al grado de desarrollo puberal alcanzado.

BACKGROUND: Body mass index (BMI) is the recommended parameter to assess the nutritional status of subjects aged less than 20 years. However, during puberty the correlation between BMI and fat mass decreases notably. Therefore, the use of BMI for the diagnosis of obesity during puberty may be misleading. AIM: To evaluate the variations of the BMI during puberty according to chronological and biological ages. MATERIAL AND METHODS: Descriptive cross sectional study in school age children of elementary and high schools (4,531 males and 5,326 females) representing all socioeconomic strata of 4 regions of Chile. BMI was calculated from weight and height measurements (W/H2) and pubertal development was evaluated according to Tanner stages. The sample selected to evaluate the variations of BMI according to chronological age and pubertal stages consisted in 3,913 females aged 8-14 years and 2,494 males aged 10-16 years. Analyses of variance (F test) and Tukey HSD test were used to compare mean BMI according to chronological and biological ages. RESULTS: The age of onset of puberty (Tanner Stages IB2 and G2) varied greatly, from 8 to 14 years in females and 10 to 16 years in males. Mean BMI in a specific stage of pubertal development did not show significant differences according to age in both sexes. However, there were significant differences (p < 0.05) in mean BMI when comparing children of the same chronological age but in different Tanner stages. Per each stage of Tanner development, BMI increased 1.0 or more points among females and 0.6 points among males. CONCLUSIONS: During puberty, BMI is associated to biological and not chronological age.