Fitness, Food, and Biomarkers: Characterizing Body Composition in 19,634 Early Adolescents

Nutrients. 2022 Mar 25;14(7):1369. doi: 10.3390/nu14071369.


Adolescent obesity persists as a major concern, especially in Central and Eastern Europe, yet evidence gaps exist regarding the pivotal early adolescent years. Our objective was to provide a comprehensive picture using a holistic approach of measured anthropometry in early adolescence, including body composition, cardiorespiratory fitness (CRF), and reported lifestyle characteristics. We aimed to elucidate potential sex/gender differences throughout and associations to biomarkers of disease risk for obese adolescents.

Methods: Trained nurses measured 19,634 early adolescents (12-14-year-olds), we collected parental reports, and, for obese adolescents, fasting blood samples in four major Polish cities using a cross-sectional developmental design.

Results: 24.7% boys and 18.6% girls were overweight/obese, and 2886 had BMI ≥ 90th percentile. With increasing age, there was greater risk of obesity among boys (p for trend = 0.001) and a decreasing risk of thinness for girls (p for trend = 0.01). Contrary to debate, we found BMI (continuous) was a useful indicator of measured fat mass (FM). There were 38.6% with CRF in the range of poor/very poor and was accounted for primarily by FM in boys, rather than BMI, and systolic blood pressure in girls. Boys, in comparison to girls, engaged more in sports (t = 127.26, p < 0.0001) and consumed more fast food (t = 188.57, p < 0.0001) and sugar-sweetened beverages (167.46, p < 0.0001). Uric acid, a potential marker for prediabetes, was strongly related to BMI in the obese subsample for both boys and girls. Obese girls showed signs of undernutrition.

Conclusion: these findings show that overweight/obesity is by far a larger public health problem than thinness in early adolescence and is characterized differentially by sex/gender. Moreover, poor CRF in this age, which may contribute to life course obesity and disease, highlights the need for integrated and personalized intervention strategies taking sex/gender into account.

Keywords: Central and Eastern Europe; PoZdro!; adiposity; adolescents; anthropometry; body mass index; fat mass; junk food; lifestyle; obesity; sex differences; undernutrition.

MeSH terms

  • Adolescent
  • Biomarkers
  • Body Composition
  • Body Mass Index
  • Cross-Sectional Studies
  • Female
  • Humans
  • Male
  • Overweight* / epidemiology
  • Pediatric Obesity* / epidemiology
  • Pediatric Obesity* / etiology
  • Thinness


  • Biomarkers