Paulina Correa-Burrows

Healthy Chilean Adolescents with HOMA-IR ≥ 2.6 Have Increased Cardiometabolic Risk: Association with Genetic, Biological, and Environmental Factors

Objective. To determine the optimal cutoff of the homeostasis model assessment-insulin resistance (HOMA-IR) for diagnosis of the metabolic syndrome (MetS) in adolescents and examine whether insulin resistance (IR), determined by this method, was related to genetic, biological, and environmental factors. Methods. In 667 adolescents (16.8 ± 0.3 y), BMI, waist circumference, glucose, insulin, adiponectin, diet, and physical activity were measured. Fat and fat-free mass were assessed by dual-energy X-ray absorptiometry. Family history of type 2 diabetes (FHDM) was reported. We determined the optimal cutoff of HOMA-IR to diagnose MetS (IDF criteria) using ROC analysis. IR was defined as HOMA-IR values above the cutoff. We tested the influence of genetic, biological, and environmental factors on IR using logistic regression analyses. Results. Of the participants, 16% were obese and 9.4 % met criteria for MetS. The optimal cutoff for MetS diagnosis was a HOMA-IR value of 2.6. Based on this value, 16.3% of participants had IR. Adolescents with IR had a significantly higher prevalence of obesity, abdominal obesity, fasting hyperglycemia, and MetS compared to those who were not IR. FHDM, sarcopenia, obesity, and low adiponectin significantly increased the risk of IR. Conclusions. In adolescents, HOMA-IR ≥ 2.6 was associated with greater cardiometabolic risk.

High cardiometabolic risk in healthy Chilean adolescents: associations with anthropometric, biological and lifestyle factors.

Objective To analyse the prevalence of cardiovascular risk factors in healthy adolescents of low to middle socio-economic status and to study the influence of anthropometric, biological and lifestyle factors on the risk of metabolic syndrome (MetS). Design Cross-sectional study. BMI, waist circumference, blood pressure, fat and lean mass (by dual-energy X-ray absorptiometry), TAG, HDL-cholesterol, glucose, insulin, homeostatic model assessment–insulin resistance index (HOMA-IR), food intake and physical activity were measured. Cardiovascular risk factors were defined using the International Diabetes Federation criteria and insulin resistance using HOMA-IR ≥2·6. Bivariate and multivariate regressions examined the associations between MetS and anthropometric, biological and lifestyle factors. Setting Observational cohort study including Chilean adolescents, who were part of a follow-up study beginning in infancy. Subjects Adolescents aged 16–17 years (n 667). Results In the sample, 16·2 % had obesity and 9·5 % had MetS. Low HDL-cholesterol (69·9 %), abdominal obesity (33·3 %) and fasting hyperglycaemia (8·7 %) were the most prevalent cardiovascular risk factors. In males, obesity (OR=3·7; 95 % CI 1·2, 10·8), insulin resistance (OR=3·0; 95 % CI 1·1, 8·2), physical inactivity (OR=2·9; 95 % CI 1·1, 7·7) and sarcopenia (OR=21·2; 95 % CI 4·2, 107·5) significantly increased the risk of MetS. In females, insulin resistance (OR=4·9; 95 % CI 1·9, 12·6) and sarcopenia (OR=3·6; 95 % CI 1·1, 11·9) were significantly associated with MetS. Conclusions High prevalences of obesity, abdominal obesity, dyslipidaemia, fasting hyperglycaemia and MetS were found in healthy adolescents. In both sexes, sarcopenia and insulin resistance were important risk factors of MetS. Promotion of active lifestyles at the school level and regulation of the sale of energy-dense foods are needed.

Physically active Chilean school kids perform better in language and mathematics

We examined the association between the engagement in regular physical activity (PA) and the academic performance (AP) of school-age children from Santiago Metropolitan Region. In a random sample of 1271 students (13.3 ± 2.3 years old) we measured regular PA, accounting for hours of weekly scheduled exercise, and AP, using national standardized tests scores in Language and Mathematics. Bivariate and multivariate regression analyses were used to model the relation between academic and health-related behaviors. Two outcomes were considered: (i) sufficiency according to the Ministry of Education and (ii) discretionary sufficiency (tests z-scores ≥50th percentile). About 80% of students were poorly engaged in scheduled exercise (<2 h per week). Devoting more than 4 h per week to scheduled exercise significantly increased the odds of reaching the official and discretionary sufficiency in both Language and Mathematics. Moderate engagement (2-4 h per week) just improved the odds of reaching the discretionary sufficiency standard. These results confirm the poor engagement in regular exercise at the school level. School kids with the highest allocation of time to scheduled exercise have better AP in Language and Mathematics. Our findings support the notion that academic and health-related behaviors are linked and, similarly, that school health programs may have positive effects on educational outcomes.

The relationship between unhealthy snacking at school and academic outcomes: a population study in Chilean schoolchildren

OBJECTIVE We examined the association between unhealthy snacking at school and academic outcomes in students from the Santiago Metropolitan Region (Chile). DESIGN Cross-sectional population-based study. SETTING We measured the nutritional quality of snacks at school using an FFQ, and accounting for the amounts of saturated fat, fibre, sugar and salt in the foods, and academic outcomes using national standardized test scores in Language and Mathematics. Multivariate regression analyses modelled the relationship between unhealthy snacking at school (exposure), potential confounders and performance in Mathematics and Language (outcomes). SUBJECTS Random sample of 1073 students (13.1 (SD 2.3) years old) attending public, partially subsidized and private schools. RESULTS Fifty-six per cent of students ate items at snack time that were high in fat, sugar, salt and energy, and thus were considered to have unhealthy snaking. Thirty-six per cent and 8% were considered to have poor-to-fair and healthy snacking, respectively. Unhealthy snacking significantly lowered the odds of good academic performance in both domains. Students having unhealthy snacks were 56% less likely to pass in Language (fully adjusted OR = 0.44; 95% CI 0.23, 0.85) and 66% less likely to pass in Mathematics (fully adjusted OR = 0.34; 95% CI 0.19, 0.64) compared with students having healthy snack items. CONCLUSIONS Schoolchildren eating unhealthy foods at snack time had worse academic performance in Language and Mathematics, as measured by a standardized test. Although association does not imply causation, these findings support the notion that academic and health-related behaviours are linked. More research is needed on the effect of school health programmes on educational outcomes.

Scheduled physical activity is associated with better academic performance in Chilean school-age children.

BACKGROUND This study was carried out to examine the association between systematic physical activity and academic performance in school kids after controlling for potential sociodemographic and educational confounders. METHODS In a random sample of 1271 students from urban Santiago, attending 5th and 9th grade, who took the 2009 System for the Assessment of Educational Quality (SIMCE) tests, we measured physical activity habits, anthropometric characteristics, and socioeconomic status. Academic performance was measured by the standardized SIMCE tests. Logistic regressions assessed the relationship between the allocation of time to weekly scheduled exercise, potential confounding factors, and individual academic performance. RESULTS About 80% of students reported less than 2 hours of weekly scheduled exercise, while 10.6% and 10.2% reported 2 to 4 hours/week and more than 4 hours/week, respectively. Devoting more than 4 hours/week to scheduled exercise significantly increased (P < .01) the odds of having SIMCE composite z-scores ≥ 50th percentile (OR: 2.3, 95% CI: 1.4 to 3.6) and ≥ 75th percentile (OR: 2.1, 95% CI: 1.3-3.3). CONCLUSIONS Better academic performance was associated with a higher allocation of time to scheduled exercise in school-age children.

Nutritional quality of diet and academic performance in Chilean students

Abstract Objective To explore associations between the nutritional quality of diet at age 16 years and academic performance in students from Santiago, Chile. Methods We assessed the nutritional quality of diet, using a validated food frequency questionnaire, in 395 students aged 16.8 ± 0.5 years. Depending on the amount of saturated fat, fibre, sugar and salt in the foods, diet was categorized as unhealthy, fair or healthy. Academic performance was assessed using high school grade-point average (GPA) and tests for college admission in language and mathematics. Academic results on or above the 75th percentile in our sample were considered good academic performance. We tested associations between nutritional quality of diet and good academic performance using logistic regression models. We considered sociodemographic, educational and body-mass index (BMI) factors as potential confounders. Findings After controlling for potential confounding factors, an unhealthy diet at age 16 years was associated with reduced academic performance. Compared to participants with healthy diets, those with unhealthy diets were significantly less likely to perform well based on language tests (odds ratio, OR: 0.42; 95% confidence interval, CI: 0.18–0.98) mathematics tests (OR: 0.35; 95% CI: 0.15–0.82) or GPA (OR: 0.22; 95% CI: 0.09–0.56). Conclusion In our sample, excessive consumption of energy-dense, low-fibre, high-fat foods at age 16 years was associated with reduced academic performance.

Low muscle mass is associated with cardiometabolic risk regardless of nutritional status in adolescents: A cross-sectional study in a Chilean birth cohort

Increased cardiometabolic risk (CMR) is documented in obese and non‐obese adolescents with low muscular fitness. However, the association of low muscle mass (LMM) with CMR, independent of weight status, has not been examined. We analyzed the relationship of LMM with CMR in adolescents, regardless of their weight status.

Leptin status in adolescence is associated with academic performance in high school: a cross-sectional study in a Chilean birth cohort

Objective Leptin is a pleiotropic hormone associated with learning and memory via brain receptors. However, elevated plasma leptin levels may impair cognitive and memory functions. Since individual differences in memory performance affect students’ ability to learn, we aimed to study the relation between leptin status in adolescence and school performance. Design and setting We studied 568 adolescents aged 16–17 years from Santiago. A cross-sectional analysis was carried out on a birth cohort conducted in Santiago (Chile). Primary and secondary outcome measures We measured serum leptin concentration using an enzyme-linked immunosorbent assay. Cut-offs from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Study for 16-year-olds were used to define abnormally high leptin levels (hyperleptinaemia). Academic performance was measured using high-school grades and grade point average (GPA). Data were collected in 2009–2012; data analysis was performed in 2014. Results 15% of participants had hyperleptinaemia. They had significantly lower school grades and GPA compared with participants with normal leptin levels (eg, GPA mean difference=33.8 points). Leptin levels were negative and significantly correlated with school grades in 9th, 10th and 12th. Similarly, it was negatively correlated with high-school GPA. After controlling for health, sociodemographic and education confounders, the chances of having a performance ≥75th centile in students having hyperleptinaemia were 32% (95% CI 0.19% to 0.89%) that of students having normal serum leptin concentration. Conclusions In high school students, abnormally high levels of leptin were associated with poorer academic performance. These findings support the idea of a relationship between leptin and cognition. Further research is needed on the cognitive effects of leptin in younger populations.

Inactive Lifestyles and Obesity in Chilean Youth: Individual Costs in Health-Related Choices.

Objective: A recent economic approach suggests that people do not account for the long-term implications of unhealthy behaviours, preventing them from performing a fully rational trade-off between current benefits and future costs, leading to negative health outcomes. We examined whether the current allocation of time to physical activity among young people leads to outcomes that may affect their well being as youth and their longer–term life prospects. Design: The study group comprised a random sample of 1692 high-school students (14.8±0.7 years old) from urban Santiago, Chile attending private and non-private schools. Setting: We measured physical activity habits accounting for time spent in class, studying and screen-based entertainment, hours of daily recreational activity and hours of weekly scheduled exercise. Obesity and abdominal obesity were diagnosed according to CDC/NCHS 2000, NHANES III and IDF criteria, respectively. Method: Logistic regression analysis was performed to assess the relationship between current physical activity habits, confounders and the likelihood of suffering from obesity and abdominal obesity. Results: Young people reporting the lowest allocation of time to physical activity, scheduled exercise and active play showed a higher risk of obesity and abdominal obesity. Those reporting moderate allocation of time to physical activity, scheduled exercise and active play were more likely to suffer from central obesity as defined by IDF criteria. Study participants attending partially subsidized schools showed the highest risk of obesity and central obesity. Conclusions: In this sample, young people appear not to be employing optimal strategies for making weight-related choices, since reduced physical activity, obesity and central obesity are proximate causes of metabolic and cardiovascular disorders.

Achievement in mathematics and language is linked to regular physical activity: a population study in Chilean youth.

Abstract We examined the association between the allocation of time to regular physical activity (PA) and achievement in mathematics and language in Chilean adolescents after controlling for confounders. In a random sample of 620 ninth graders (15.6 ± 0.7 years old), we measured regular PA, including physical education and sports extracurricular activities, and academic performance, using national standardised tests. Bivariate and multivariate regression analyses modelled the relation between academic and health-related behaviours. Sufficiency and proficiency in mathematics and language were used as outcome variables. Only 18% of adolescents had >4 h·week–1 of regular PA. Devoting >4 h · week–1 to regular PA significantly increased the odds of sufficiency and proficiency in both domains. After full adjustment, the odds of sufficiency and proficiency in mathematics increased by 1.9 (95% CI: 1.1–3.5) and 2.7 (95% CI: 1.7–4.3), respectively. Similarly, the odds of sufficiency and proficiency in language increased by 3.3 (95% CI: 1.7–9.7) and 2.6 (95% CI: 1.6–4.1), respectively. Adolescents with the highest allocation of time to regular PA performed much better in mathematics and language than inactive students. The academic benefits associated with PA can help to promote sustained behaviour changes regarding lifestyles. They can be more easily perceived as gains than health benefits alone.