Introduction

This study examined changes in substance use from adolescence to young adulthood as related to adolescents' risk taking, sensation seeking, antisocial activities, and personality traits.

Methods

Chilean youth (N = 890, 52% female) were studied in adolescence (14.5 and 16.2 years) and young adulthood (M age 21.3 years). Risk taking was assessed via a laboratory-based performance task (Balloon Analogue Risk Task), and self-administered questionnaires assessed sensation seeking, antisocial behaviors, personality and substance use.

Results

Frequent involvement in sensation seeking and antisocial activities were associated with increased odds of continued marijuana use from adolescence to young adulthood and of illicit substance use at young adulthood. High risk taking was associated with a reduced likelihood of discontinuing marijuana use at young adulthood, and high agreeableness and conscientiousness were associated with reduced likelihood of new onset marijuana use and illicit substance use at young adulthood.

Conclusions

Results highlight specific risk-taking tendencies and personality characteristics that relate to initiating, continuing, or discontinuing substance use at entry into adulthood. Sensation seeking and involvement in antisocial activities were the two foremost risk factors for continued use, which is a forecaster of drug dependence. Findings suggest potential prevention and intervention targets for abstaining from or discontinuing substance use as youth transition to adulthood.

Introduction

Obesity and metabolic syndrome (MetS) indicators have increased globally among the pediatric population. MetS indicators in the young elevate their risk of cardiovascular disease and metabolic disorders later in life. This study examined early onset obesity as a risk factor for MetS risk in adolescence.

Methods

A cohort of Chilean participants (N = 673) followed from infancy was assessed at age 5 years and in adolescence (mean age, 16.8 y). Adiposity was measured at both time points; blood pressure and fasting blood samples were assessed in adolescence only. Early onset obesity was defined as a World Health Organization z score of 2 standard deviations (SDs) or more for body mass index (BMI) at age 5 years. We used linear regression to examine the association between early onset obesity and adolescent MetS risk z score, adjusting for covariates.

Results

Eighteen percent of participants had early onset obesity, and 50% of these remained obese in adolescence. Mean MetS risk z score in adolescence was significantly higher among those with early onset obesity than among those without (1.0; SD, 0.8 vs 0.2; SD, 0.8 [P < .001]). In the multivariable model, early onset obesity independently contributed to a higher MetS risk score in adolescence (β = 0.27, P < .001), controlling for obesity status at adolescence and sex, and explained 39% of the variance in MetS risk.

Conclusion

Early onset obesity as young as age 5 years relates to higher MetS risk.

We explored the association between excess body fat and academic performance in high school students from Santiago, Chile. In 632 16-year-olds (51% males) from low-to-middle socioeconomic status (SES), height, weight, and waist circumference were measured. Body-mass index (BMI) and BMI for age and sex were calculated. Weight status was evaluated with 2007 World Health Organization (WHO) references. Abdominal obesity was diagnosed with International Diabetes Federation (IDF) references. Total fat mass (TFM) was measured with dual-energy X-ray absorptiometry (DXA). TFM values ≥25% in males and ≥35% in females were considered high adiposity. School grades were obtained from administrative records. Analysis of covariance examined the association of fatness measures with academic performance, accounting for the effect of diet and physical activity, and controlling SES background and educational confounders. We found that: (1) having obesity, abdominal obesity, or high adiposity was associated with lower school performance alone or in combination with unhealthy dietary habits or reduced time allocation for exercise; (2) high adiposity and abdominal obesity were more clearly related with lower school grades compared to obesity; (3) the association of increased fatness with lower school grades was more salient in males compared to females.

Background

Obesity is a risk factor for insulin resistance (IR) and metabolic disease.

Objective

To examine potential metabolic pathways linking childhood weight status to adolescent IR and metabolic risk.

Methods

Participants were 600 low- to middle-income Chilean adolescents from a cohort studied since infancy as part of an iron deficiency anemia preventive trial and follow-up study. We examined body mass index z-score at 10 y (BMIz-10y) and blood pressure, total fat, and fasting glucose, adiponectin to leptin ratio (A:L), ghrelin, and HOMA-IR at 16 y. A total count for metabolic risk factors (MRF) was calculated using the International Diabetes Federation criteria. We used path analysis to estimate pathways and model indirect effects from BMIz-10y, controlling for child age and sex and maternal body mass index (BMI).

Results

Participants were 54% male; mean BMIz-10y of 0.53 (SD = 1.02); mean MRF of 1.3 (SD = 0.9); mean HOMA-IR of 1.8 (SD = 1.3). Path analysis showed that BMIz-10y directly and indirectly related to increased MRF via A:L and HOMA-IR. Ghrelin was not in the metabolic pathway from BMIz-10y to MRF but was related to MRF via HOMA-IR.

Conclusion

These results elucidate metabolic pathways involving child weight status, IR and metabolic risk in adolescents. Childhood BMI was an indirect risk factor for adolescent cardiometabolic risk via several pathways that involved BMI, appetite hormones, markers of inflammation, and insulin resistance during adolescence. Findings illustrate the adverse effect that childhood obesity has on adolescent health outcomes, which sets precedence for health outcomes over the life course.

Evidence for the association between breastfeeding (BF) duration and later body mass index (BMI) is inconsistent. We explored how BF duration and BF type (exclusive or partial) related to BMI from childhood to young adulthood in a Chilean cohort. Infants were recruited at 6 months between 1994 and 1996 in Santiago, Chile (n = 821). Mothers reported date of first bottle and last BF; anthropometry was measured at 1, 5, 10, 16, and 23 years. We tested whether: (1) type of BF at 6 months (none, partial, exclusive) and (2) duration of exclusive BF (<1 month, 1 to <3 months, 3 to <6 months, and ≥6 months) related to BMI. At 6 months, 35% received both breastmilk and formula ("partial BF") and 38% were exclusively breastfed. We found some evidence of an association between longer BF and lower BMI z-scores at young ages but observed null effects for later BMI. Specifically, BF for 3 to <6 months compared to <1 month related to lower BMI z-scores at 1 and 5 years (both p < 0.05). Our results are in partial accordance with others who have not found a protective effect of longer BF for lower BMI.

Although numerous studies have approached the effects of exposure to a Western diet (WD) on academic outcomes, very few have focused on foods consumed during snack times. We explored whether there is a link between nutritious snacking habits and academic achievement in high school (HS) students from Santiago, Chile. We conducted a cross-sectional study with 678 adolescents. The nutritional quality of snacks consumed by 16-year-old was assessed using a validated food frequency questionnaire. The academic outcomes measured were HS grade point average (GPA), the likelihood of HS completion, and the likelihood of taking college entrance exams. A multivariate analysis was performed to determine the independent associations of nutritious snacking with having completed HS and having taken college entrance exams. An analysis of covariance (ANCOVA) estimated the differences in GPA by the quality of snacks. Compared to students with healthy in-home snacking behaviors, adolescents having unhealthy in-home snacks had significantly lower GPAs (M difference: -40.1 points, 95% confidence interval (CI): -59.2, -16.9, d = 0.41), significantly lower odds of HS completion (adjusted odds ratio (aOR): 0.47; 95% CI: 0.25-0.88), and significantly lower odds of taking college entrance exams (aOR: 0.53; 95% CI: 0.31-0.88). Unhealthy at-school snacking showed similar associations with the outcome variables. Poor nutritional quality snacking at school and at home was associated with poor secondary school academic achievement and the intention to enroll in higher education.

Objective

Stress derived from socioeconomic disadvantage can be damaging to mental and physical health. This study uses longitudinal data on a large prospectively studied cohort to examine how socioeconomic hardship during childhood leads to hypertension in young adulthood by its effects on family conflict, anxiety-depression, and body mass.

Method

Data are from 1,039 participants of the Santiago Longitudinal Study who were studied in childhood (M age 10 years), adolescence (14-17 years), and young adulthood (21-26 years). As young adults, 26% had elevated blood pressure or hypertension.

Results

Children from more economically disadvantaged families experienced higher levels of family conflict, which related to significant increases in anxiety-depression and body mass over time, both of which were directly linked to hypertension in young adulthood.

Conclusions

Findings provide an understanding of how early-life adversity associated with socioeconomic hardship manifests as stress-related health problems in adulthood. Intervention efforts that target overweight/obesity and anxiety and depression that stem from childhood poverty might be useful for reducing the socioeconomic disparities in adult health.

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.

Background

This study investigates the cross-sectional and prospective associations between accelerometer-measured sedentary behavior and body composition from adolescence to early adulthood.

Methods

Data from the Santiago Longitudinal Study were analyzed (n = 212). Sedentary time was measured at age 16 years, and body composition (body mass index [BMI], waist circumference, waist-to-height ratio [WHtR], fat mass percentage, and lean mass percentage) was examined at both age 16 and 23 years. Adjusted linear regression models estimated associations between sedentary time, sedentary bout duration, and body composition, overall and by sex.

Results

In all analyses, mean sedentary bout duration was not associated with body composition. In cross-sectional analyses, more sedentary time during adolescence was significantly associated with lower BMI, waist circumference, WHtR, fat mass percentage, and higher lean mass percentage (p < 0.05). One standard deviation increase in daily sedentary time was prospectively associated with lower body mass index (β = -1.22 kg/m², 95% CI: -2.02, -0.42), waist circumference (β = -2.39 cm, 95% CI: -4.03, -0.75), and WHtR (β = -0.014, 95% CI: -0.024, -0.004). Sedentary time at 16 years was not associated with changes in body composition from 16 to 23 years.

Conclusions

Sedentary behavior in adolescence is not adversely associated with body composition profiles in early adulthood.

Impact

Little is known about the effect of device-measured sedentary behavior on body composition during the transition from adolescence to early adulthood. Among participants in the Santiago Longitudinal Study, more accelerometer-measured sedentary time during adolescence was associated with lower BMI, waist circumference, and waist-to-height ratio in early adulthood though point estimates were generally small in magnitude. Sedentary behavior in adolescence was not detrimentally associated with healthy body composition profiles in early adulthood. Public health interventions aimed at reducing obesity rates could consider other behaviors, such as physical activity and healthy diet, instead of sitting time.

Growth in early infancy is hypothesized to affect chronic disease risk factors later in life. To date, most reports draw on European-ancestry cohorts with few repeated observations in early infancy. We investigated the association between infant growth before 6 months and lipid levels in adolescents in a Hispanic/Latino cohort. We characterized infant growth from birth to 5 months in male (n = 311) and female (n = 285) infants from the Santiago Longitudinal Study (1991-1996) using 3 metrics: weight (kg), length (cm), and weight-for-length (g/cm). Superimposition by translation and rotation (SITAR) and latent growth mixture models (LGMMs) were used to estimate the association between infant growth characteristics and lipid levels at age 17 years. We found a positive relationship between the SITAR length velocity parameter before 6 months of age and high-density lipoprotein cholesterol levels in adolescence (11.5, 95% confidence interval; 3.4, 19.5), indicating higher high-density lipoprotein cholesterol levels occurring with faster length growth. The strongest associations from the LGMMs were between higher low-density lipoprotein cholesterol and slower weight-for-length growth, following a pattern of associations between slower growth and adverse lipid profiles. Further research in this window of time can confirm the association between early infant growth as an exposure and adolescent cardiovascular disease risk factors.