Early-life determinants of undernutrition and overweight/obesity in Polish toddlers

Rationale

Undernutrition and overweight /obesity represent a double burden of malnutrition, emerging already in early childhood. However, their determinants in children under 3 years remain insufficiently understood.

Methods

This cross-sectional study was conducted in a sample of Polish children aged 13–36 months (n = 1,373), with data collected at three time points (2010, 2016, 2024). Nutritional status was assessed using weight-for-height z-scores (WHZ) according to WHO standards. In an initial step, Selected socio-demographic variables (parental age and education) were included as covariates. Multivariable logistic regression models were then applied separately for undernutrition and overweight, including birth weight, child age, breastfeeding, material situation and survey year,.

Results

Undernutrition was observed in 6,3% of children (n = 86), and overweight/obesity in 9.8% (n = 134). Breastfeeding was associated with lower odds of both undernutrition (OR = 0.56; p = 0.043) and overweight/obesity (OR = 0.60; p = 0.041). High birth weight (above 4 kg) was strongly associated with increased odds of overweight/obesity (OR = 4.72; p = 0.007). Better material situation showed a borderline protective effect for undernutrition (OR = 0.66; p = 0.064). No significant associations were found for, parental age, parental education, child age, or survey year.

Conclusions

Nutritional outcomes in children aged 13–36 months appear to be driven primarily by early-life biological and feeding-related factors rather than socio-economic characteristics. Breastfeeding plays a protective role across both forms of malnutrition, while hight birth weight is a key risk factor for overweight/obesity. These findings support the need for early-life interventions, particularly building awareness of the role of nutrition during the first 1000 days and targeted monitoring of high-risk children, to prevent both undernutrition and overweight/obesity

The study was funded by the Nutricia Foundation

Key messages

• Early-life factors; not socio-economic status, drive both undernutrition and overweight in toddlers. Breastfeeding protects, while high birth weight strongly increases obesity risk.

• Findings highlight the first 1000 days as critical: promoting breastfeeding and monitoring high-birth-weight infants can prevent both undernutrition and excess weight.