Discrepancies in reporting lifestyle and dietary habits by children and parents and their association with anthropometric parameters in 10–12-year-old Polish students: a cross-sectional study

Although parents seek the best for their children, discrepancies often arise between what children and parents report about their lifestyles, including diet quality. To address this gap, this study aimed to assess the relationships between selected lifestyle determinants, diet quality, and nutritional knowledge, and anthropometric parameters in Polish children aged 10–12, taking into account discrepancies between children’s self-assessment and their parents’ reports. A cross-sectional, nationwide study of 4,407 Polish schoolchildren aged 10–12, based on children and their parents’ reports, was conducted between 2022 and 2023. Data on diet quality, nutritional knowledge, lifestyle determinants (screen time, physical activity, sleep duration), and sociodemographic data were collected using a paper questionnaire. Anthropometric measurements included body weight, height, and waist circumference, from which the Body Mass Index (BMI) and Waist-to-Height Ratio (WHtR) indices were calculated to assess weight status and central obesity, respectively. A logistic regression model was performed to assess how these lifestyle and dietary factors predict BMI and WHtR. Predictive models indicated that excessive screen time (> 4 h/day), based on children’s self-reports, significantly decreased the odds of having a normal BMI and a WHtR < 0.5. Conversely, high physical activity reported by both groups strongly increased the odds of maintaining a WHtR < 0.5. Furthermore, higher child-reported nutritional knowledge increased the odds of a normal BMI, while adherence to the ‘healthy products’ dietary pattern favoured a normal WHtR. Selected lifestyle determinants among school-age children were found to be associated with BMI and WHtR indicators of nutritional status. At the same time, the significant discrepancies observed between children’s self-assessments and parental reports indicate the need to use multi-source data in the assessment of children’s lifestyles and to exercise caution when interpreting research results based solely on parental reports.