Urinary cadmium and growth faltering in children aged 3-6 years: A nationwide cross-sectional study from China

Cadmium is a persistent toxic metal that may impair child development, yet its effects on growth beyond infancy remain unclear. We examined urinary cadmium (U-Cd) levels and their associations with physical growth among preschool children in China.

We analyzed data from 10,091 children aged 36-84 months in a nationally representative survey. U-Cd concentrations were creatinine-adjusted and categorized into quartiles. Growth was assessed using WHO Z-scores for height-for-age (HAZ), weight-for-age (WAZ), and BMI-for-age (BAZ). Generalized linear models (GLMs) estimated age-specific growth trajectories from 36 to 72 months. Multivariable linear and penalized logistic regression models evaluated associations with continuous Z-scores and growth disorders (stunting, underweight, obesity). Restricted cubic splines assessed dose-response relationships.

The geometric mean U-Cd was 0.220 μg/g Cr, with higher levels in western provinces and among rural, low-income, and less-educated households. Higher U-Cd was consistently associated with lower predicted height, weight, and BMI across age groups (all P < 0.001). Each 1-unit increase in log₁₀ U-Cd was linked to decreases in HAZ (β = -0.268) and WAZ (β = -0.186), with stronger effects in girls. Elevated U-Cd increased the odds of stunting (OR = 1.395) and reduced the odds of obesity (OR = 0.841). Nonlinear analyses revealed steeper growth declines below 1 μg/g Cr, particularly in girls.

Cadmium exposure in early childhood is associated with impaired linear and ponderal growth, with greater susceptibility observed among girls and socioeconomically disadvantaged children. These findings call for targeted environmental health interventions in high-risk areas and provide evidence relevant to cadmium-affected regions globally.