Profile and reference values for body fat and skeletal muscle mass percent at females, aged from 18.0 to 69. 9, measured by multichannel segmental bioimpedance method: Serbian population study / Perfil y valores de referencia del porcentaje de grasa corporal y masa muscular en mujeres, con edades comprendidas entre 18, 0 y 69, 9 años, medido por el método de bioimpedancia segmentaria multicanal: estudio en población serbia

Profile and standards for the diagnostics of percent of body fat and muscles were defined on a sample of 1924 women from the Republic of Serbia, aged 18.0 to 69.9, where the body structure of subjects was measured by applying multichannel segmental bioimpedance. Total sample was divided into six age groups, for the purpose of the definition of standard with regards to age. When it comes to body fat percentage results have shown that the average value of the total sample was 28.51±9.26 %, and between the range of 23.81 and 39.94 % for age groups 18.0-19.9 yr and 60.0-69.9 yr, respectively. Regression analysis results have shown that the constant of body fat percentage increase by trend of 3.417 % per decade, and that 25.1 % of mutual variance trend was explained by the model, with prediction error of 4.55 %. With regards to the percentage of skeletal muscles in the body, the results have shown that the average value of the total sample was 39.30±5.25 %, and within the range of 42.25 to 32.58 % for age groups 18.0-19.9 yr and 60.0-69.9 yr, respectively. Regression analysis results have shown that the constant of the skeletal muscles decrease by tend of -2.016 % per decade and that the model explained 23.8 % of mutual variance trend with prediction error of 8.08 %.

El perfil y estándares para el diagnóstico del porcentaje de grasa corporal y masa muscular fueron definidos en una muestra de 1924 mujeres de la República de Serbia, con edades comprendidas entre 18,0 y 69,9 años, donde la composición corporal de los sujetos fue medida por bioimpedancia segmentaria multicanal. La muestra fue dividida en seis grupos, con el propósito de definir los estándares respecto a la edad. Respecto al porcentaje de grasa corporal los resultados han mostrado que el valor promedio de la muestra fue de 28,51±9,26 %, y entre los rangos de 23,81 y 39,94 para los grupos de edad de 18,0-19,9 años y 60,069,9 años, respectivamente. Los resultados del análisis de regresión mostraron que la constante del porcentaje de grasa corporal aumentó 3,417 % por década, y que un 25,1 % de la varianza fue explicada por el modelo, con un error de predicción de 4,55 %. Con respecto al porcentaje de masa muscular, los resultados han mostrado que el valor promedio de la muestra fue de 39,30±5,25 %, y entre los rangos de 42,24 y 32,58 para los grupos de edad de 18,0-19,9 años y 60,0-69,9 años, respectivamente. Los resultados del análisis de regresión han mostrado que la constante de masa muscular decreció -2,016 % por década y que el modelo explicó 23,8 % de la varianza con un error de predicción de 8,08 %.

Characteristics of eating habits and physical activity in relation to body mass index among adolescents.

OBJECTIVE: To assess eating habits and the level of physical activity in adolescents and develop a predictive model for the body mass index (BMI) based on these variables. DESIGN: In this cross-sectional study, eating habits and the level of physical activity were assessed using a questionnaire validated in adolescents. Body mass and height collected during the last annual checkup were extracted from personal medical records. SUBJECTS: The sample included 330 boys and 377 girls (mean age 15.8 ± 0.2 years) who were first-year high school students in the city of Belgrade, Serbia. MEASURES: Responses to each of the 14 questions about eating habits and 6 questions about physical activity were scored from the least (0) to the most (3) desired behaviors. These ratings were then averaged to arrive to an aggregate score for each domain. The BMI was calculated according to the standard method. A series of regression analyses was performed to derive the best model for predicting BMI in boys and girls based on individual eating habits and physical activity items, first separately and then combined. RESULTS: In the sample, 24.5% of boys and 9.5% of girls were overweight or obese. Girls' eating habits were better than boys (mean aggregate score 2.3 ± 0.3 and 2.1 ± 0.3, respectively, p < 0.001), whereas the level of physical activity was greater in boys than girls (2.1 ± 0.6 vs 1.9 ± 0.6, p < 0.001). The differences between boys and girls in the BMI, eating habits, and physical activity remained significant after controlling for their knowledge about healthy eating and education level of their parents. Eating habits were a better predictor of BMI than physical activity, particularly in boys (R (2) = 0.13 vs R (2) = 0.02) compared to girls (R (2) = 0.04 vs R (2) = 0.01). Combining eating habits and physical activity in the multivariate model of BMI resulted in a better predictive accuracy in boys (R (2) = 0.17) but not girls (R (2) = 0.04). CONCLUSIONS: Eating habits and physical activity differ between adolescent boys and girls and can predict BMI, particularly in boys. The results suggest the need to develop gender-specific programs for promoting healthy lifestyle among adolescents in our country.

Nutritional and physical activity behaviours and habits in adolescent population of Belgrade.

BACKGROUND/AIM: Proper nutrition and regular physical activity are essential parts of a adolescent's overall health. The aim of this research was to evaluated eating and physical activity behaviours and habits, nutritional and food knowledge, beliefs and self-efficacy related to diet and health of the adolescents of the city of Belgrade, Serbia. METHODS: A dietary questionnaire previously constructed and tested in adolescent population from Italy was self-administrated. We evaluated eating habits, physical activity, meaning of healthy and unhealthy dietary habits and food, self-efficacy, barriers affecting food choices, nutritional and food safety, and body mass index (BMI) of the adolescents. The sample included 707 adolescents, the mean age of 15,8 +/- 2 years enrolled in the first grade at several high schools in Belgrade. RESULTS: Only 27% of the adolescents had satisfactory eating habits; 31% have a very active lifestyle; 7% good nutritional knowledge and 6-12% satisfactory food safety knowledge and hygiene practices. CONCLUSION: Significant deviations from recommendations for healthy lifestyle was noted in adolescents' habits, knowledge and practice. It is therefore necessary to develop and organize programs for promotion of healthy behaviours adapted to the adolescents' needs.