Postnatal Growth Patterns in a Chilean Cohort: The Role of SES and Family Environment

Neurocognitive factors predicting BMI changes from adolescence to young adulthood

OBJECTIVE

The objective of this study was to assess whether inhibitory task performance in adolescence could be prospectively related to weight gain in young adulthood. We proposed that this association would differ according to the BMI group in adolescence.

METHODS

A total of 318 adolescents performed the anti-saccade task, and 530 completed the Stroop test. Accuracy and reaction time were assessed for each incentive type (neutral, loss, and reward) in the anti-saccade task and for each trial type (control and incongruent trials) in the Stroop test. Changes in the BMI z score (∆BMI z score) from adolescence to young adulthood were calculated.

RESULTS

The relationship between the BMI z score and the anti-saccade task accuracy showed an effect on the ∆BMI z score (β = -0.002, p < 0.05). The neutral and loss accuracies were related to ∆BMI z score in the groups with overweight (all β = -0.004, p = 0.05) and obesity (β = -0.006 and β = -0.005, p < 0.01). The interaction between adolescents' BMI z score with control (β = -0.312, p < 0.001) and incongruent (β = -0.384, p < 0.001) trial reaction times showed an effect on the ∆BMI z score. Control (β = 0.730, p = 0.036) and incongruent (β = 0.535, p = 0.033) trial reaction times were related to ∆BMI z score in the group with overweight.

CONCLUSIONS

Our findings support the hypothesis that cognitive vulnerability could predict the BMI gain from adolescence to young adulthood.

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.

Centre-based care is a significant predictor of lower body mass index in early childhood: Longitudinal evidence from Chile

BACKGROUND

The prevalence of childhood overweight has increased by approximately 50% in the past three decades, becoming a major public health concern worldwide. In Chile, an upper middle-income country, about 38% of children between two and four years of age are overweight, almost double the average in Latin America and the Caribbean. Various environmental and individual factors, and their interactions, affect childhood weight. Emerging evidence suggests childcare may also matter. Because the public provision of centre-based care is growing, childcare may be a useful policy tool to help prevent childhood overweight.

METHODS

Using a nationally representative longitudinal survey of ~ 15 000 children in Chile (2010 and 2012), we estimated whether the type of child care (centre-based or maternal) a child attended at age 24 to 36 months was a significant predictor of the child's sex-and-age-specific body-mass-index (BMI) at age 36-48 months. We restricted our sample to children in full-time maternal care at baseline (12-24 months of age; n = 1273), but tested the robustness of results with the full sample. We compared children in centre-based care and in maternal care using difference-in-difference estimators and propensity score matching, and adjusted our estimates using child, family, and neighborhood characteristics.

RESULTS

Children attending centre-based care had 0.27 SD lower BMI than children in maternal care at follow-up (P < 0.05). We found suggestive evidence this association may be modulated by the child's socioeconomic status and by how frequently the child watched television: we found smaller BMI changes for children at the bottom 80% of socioeconomic status (P < 0.05) and also for children who frequently watched television (P < 0.10). Our results were robust to various model specifications.

CONCLUSIONS

Our findings suggest centre-based care programs, with adequate regulation and enforcement, may be a useful support to help curb the early childhood overweight epidemic, in addition to known effects in labor supply and child development.

Sleep and motor sequence learning consolidation in former iron deficient anemic adolescents

BACKGROUND

Iron deficiency is the most prevalent micronutrient deficiency worldwide. There is evidence that iron deficiency produces alterations in the developing brain, eventually leading to long-lasting effects on various cognitive functions.

METHODS

Here, we investigated motor learning and its consolidation after sleep in adolescents who sustained iron deficiency anemia (IDA) in infancy, compared to healthy controls, in the context of a long-term follow-up Chilean research project. Fifty-three adolescents who formerly had iron deficiency anemia as infants and 40 control adolescents practiced a sequential motor finger tapping task, before and after a night of sleep. Performance was measured at the end of learning, 30 min later (boost effect), and the next morning.

RESULTS

Revealed slower learning in subjects with infant iron deficiency anemia than control subjects, followed by a proportionally similar performance boost at 30 min. Performance remained stable overnight in healthy controls but further improved in infant IDA adolescents, suggesting a beneficial effect of post-training sleep on the consolidation of incompletely learned motor skills. In particular, overnight gains in performance were observed in female, but not male infant iron deficiency anemic subjects, suggesting a gender effect.

CONCLUSIONS

Our results indicate long-lasting motor learning deficits in infant IDA adolescents and provide support to the hypothesis that post-training sleep might, to some extent, compensate for hampered motor learning during wakefulness.

Constructing and Adapting Causal and Formative Measures of Family Settings: The HOME Inventory as Illustration

Measures of the home environment are frequently used in studies of children's development. This review provides information on indices composed of causal and formative indicators (the kind of indicators often used to capture salient aspects of family environments) and to suggest approaches that may be useful in constructing such measures for diverse populations. The HOME Inventory is used to illustrate challenges scholars face in determining what to include in useful measures of family settings. To that end, a cross-cultural review of research on relations among HOME, family context, and child outcomes is presented. The end of the review offers a plan for how best to further research on relations between the home environment and child development for diverse populations.

A Review of the Relationship Between Socioeconomic Position and the Early-Life Predictors of Obesity

A range of important early-life predictors of later obesity have been identified. Children of lower socioeconomic position (SEP) have a steeper weight gain trajectory from birth with a strong socioeconomic gradient in child and adult obesity prevalence. An assessment of the association between SEP and the early-life predictors of obesity has been lacking. The review involved a two-stage process: Part 1, using previously published systematic reviews, we developed a list of the potentially modifiable determinants of obesity observable in the pre-natal, peri-natal or post-natal (pre-school) periods; and part 2, conducting a literature review of evidence for socioeconomic patterning in the determinants identified in part 1. Strong evidence was found for an inverse relationship between SEP and (1) pre-natal risk factors (pre-pregnancy maternal body mass index (BMI), diabetes and pre-pregnancy diet), (2) antenatal/peri natal risk factors (smoking during pregnancy and low birth weight) and (3) early-life nutrition (including breastfeeding initiation and duration, early introduction of solids, maternal and infant diet quality, and some aspects of the home food environment), and television viewing in young children. Less strong evidence (because of a lack of studies for some factors) was found for paternal BMI, maternal weight gain during pregnancy, child sleep duration, high birth weight and lack of physical activity in young children. A strong socioeconomic gradient exists for the majority of the early-life predictors of obesity suggesting that the die is cast very early in life (even pre-conception). Lifestyle interventions targeting disadvantaged women at or before child-bearing age may therefore be particularly important in reducing inequality. Given the likely challenges of reaching this target population, it may be that during pregnancy and their child's early years are more feasible windows for engagement.

Potential effects of reward and loss avoidance in overweight adolescents

BACKGROUND

Reward system and inhibitory control are brain functions that exert an influence on eating behavior regulation. We studied the differences in inhibitory control and sensitivity to reward and loss avoidance between overweight/obese and normal-weight adolescents.

METHODS

We assessed 51 overweight/obese and 52 normal-weight 15-y-old Chilean adolescents. The groups were similar regarding sex and intelligence quotient. Using Antisaccade and Incentive tasks, we evaluated inhibitory control and the effect of incentive trials (neutral, loss avoidance, and reward) on generating correct and incorrect responses (latency and error rate).

RESULTS

Compared to normal-weight group participants, overweight/obese adolescents showed shorter latency for incorrect antisaccade responses (186.0 (95% CI: 176.8-195.2) vs. 201.3 ms (95% CI: 191.2-211.5), P < 0.05) and better performance reflected by lower error rate in incentive trials (43.6 (95% CI: 37.8-49.4) vs. 53.4% (95% CI: 46.8-60.0), P < 0.05). Overweight/obese adolescents were more accurate on loss avoidance (40.9 (95% CI: 33.5-47.7) vs. 49.8% (95% CI: 43.0-55.1), P < 0.05) and reward (41.0 (95% CI: 34.5-47.5) vs. 49.8% (95% CI: 43.0-55.1), P < 0.05) compared to neutral trials.

CONCLUSION

Overweight/obese adolescents showed shorter latency for incorrect responses and greater accuracy in reward and loss avoidance trials. These findings could suggest that an imbalance of inhibition and reward systems influence their eating behavior.

Inhibitory control in otherwise healthy overweight 10-year-old children

BACKGROUND

Preventing obesity is a worldwide public health priority. In vulnerable children living in obesogenic environments, with easy access to high-caloric food, alterations in inhibitory control functions might favor excessive food intake and affect energy regulation. We hypothesized that overweight/obese children would present lower inhibitory control in comparison to normal weight children.

METHODS

We measured inhibitory control functions in 93 otherwise healthy overweight/obese and 92 normal weight 10-year-old children using the Stroop test and the Go/No-Go task. Event-related potentials were recorded during the Go/No-Go task.

RESULTS

Overweight/obese children showed slower reaction times (1248.6 ms (95% confidence interval (CI): 1182.9-1314.3) vs 1149.0 ms (95% CI: 1083.0-1215.1)) on the Stroop test, higher reaction time variability (0.25 (95% CI: 0.22-0.27) vs 0.21 (95% CI: 0.19-0.24)) on the Go/No-Go task and decreased P300 amplitude (4.1 μV (95% CI: 3.0-5.2) vs 6.4 μV (95% CI: 5.2-7.6)) on event-related potentials compared with normal weight children.

CONCLUSIONS

Our results indicate altered inhibitory control functions in otherwise healthy overweight/obese children, which might contribute to their excessive food consumption.