Most of the schools was indeed classified by the Chilean Ministry of Studies towards three profile, specifically reasonable-achieving universities, mid-achieving universities and you may highest-gaining universities, centered this new abilities of its people throughout SIMCE examination ( 32 ) .
Anthropometric measurements and you can nutritional reputation
Standardized procedures were used to measure students’ weight to the nearest 0·1 kg, using a Seca scale (SECA, Hamburg, Germany), and height to the nearest 0·1 cm, using a Holtain stadiometer. All instruments were verified before measuring each participant ( Reference Gibson 33 ) . BMI (kg/m 2 ) and height-for-age were evaluated, and Z-scores were obtained according to the references of the Centers for Disease Control, National Center for Health Statistics (USA) ( Reference Kuczmarski, Ogden and Guo 34 ) . Nutritional status was defined as follows: underweight, BMI Z-score
Socio-monetary position
Socio-monetary condition (SES) is counted playing with a size predicated on Graffar’s altered strategy which is actually adjusted in order to Chilean metropolitan and you may outlying populations ( Resource Alvarez, Muzzo and Ivaple towards four socio-financial teams: 1=highest (0·3 %); 2=mid–higher (14·seven %); 3=middle (step three8·3 %); 4=mid–lower (45·six %); and you can 5=low (1·1 %). However, within studies we matched these five groups into three: high (1+2), center (3) and you may lowest (4+5) SES.
Analytical research
Statistical analysis included performing ? 2 tests to compare categorical variables, and ANOVA and Bonferroni tests for comparison of continuous variables. After performing bivariate analyses with each potential confounding variable, including sex, grade, nutritional status, SES and school’s performance, we used logistic regression to assess the relationship between the nutritional quality of snacks at school (exposure) and individual academic performance in Mathematics and Language (outcome). In each case, the probability of passing the test was estimated using three models. In the second model, SES was added. Finally, a fully adjusted model contained all mentioned covariates with the addition of a variable denoting the school’s academic performance. Because the variable school’s performance was partly derived from the outcome variables, this adjustment may cause underestimation of the association, so we included models with and without adjustment for school’s performance. A P value of <0·05 denoted statistical significance. Data were processed using the statistical software package Stata SE for Windows version 12·0.
Results
The test was developed right up away from 13·1 ( sd dos·3) year-dated men (52 %) and you may women (forty-eight %) adolescents off reduced (44·3 %), center (39·6 %) and 
you will high (step one6·step one %) SES. It attended 5th (51·9 %) and you can 9th (48·1 %) level in public areas (34·8 %), partly sponsored (57·8 %) and personal schools (7·4 %) in the Santiago Urban Part. For health reputation, forty-five % regarding participants was obese or over weight. Almost 1 / 2 of the students (forty-eight %) went to higher-finding colleges, while 29 % and you will 23 % attended middle- and you may lowest-finding schools, correspondingly.
On the attempt, 56 % regarding people advertised use of issues from the treat date which were stuffed with lbs, glucose, sodium and energy. Thirty-half dozen % had been regarded as to own terrible-to-reasonable snack, while simply 8 % were thought to eat match circumstances when you look at the treat go out at the university. Desk step 1 has the descriptive analytics of one’s decide to try. Average thinking from ratings during the Language and Mathematics have been significantly ong individuals with down nutritional quality of meals at school (P=0·01). The newest share out-of students taking below average ingredients at school is actually notably high one of 9th graders (59 %; P=0·040), people going to reduced-reaching colleges (61 %; P=0·036), and certainly underweight and you will typical-lbs players (69 % and you may 62 %, respectively; P=0·006).
