Single-Parent Family Structure and Children’s BMI: The Mediating Role of Socioeconomic Status

Objectives: Previous research has consistently shown that children living in single-parent families are at greater risk of overweight and obesity. However, the mechanisms underlying this association remain insufficiently understood. Socioeconomic disadvantage may represent an important pathway linking family structure to children’s weight outcomes. This study examined whether socioeconomic status (SES) mediates the association between single-parent family structure and children’s BMI z-scores. Methods: Data were obtained from the Croatian Childhood Obesity Surveillance Initiative (CroCOSI) conducted during the 2021/2022 school year. The sample comprised 5425 children aged 6–10 years. Family structure was specified as the independent variable, BMI z-score as the outcome variable, and SES as the mediator. Age, gender, region, and urbanicity were included as covariates in the mediation model. Results: Children living in single-parent families had significantly lower SES than children living in two-parent families. Higher SES was associated with lower BMI z-scores. The indirect effect of family structure on BMI z-score through SES was statistically significant, whereas the direct effect was not statistically significant. These findings indicate that SES mediates the association between single-parent family structure and children’s BMI. Conclusions: The findings suggest that socioeconomic disadvantage is an important mechanism linking single-parent family structure to childhood weight outcomes. Efforts to reduce childhood obesity should therefore extend beyond individual behavioral interventions and address broader socioeconomic inequalities affecting families. Policies aimed at improving the socioeconomic conditions of single-parent families may contribute to reducing disparities in childhood obesity and promoting healthier developmental outcomes among children.