Associations Between Hair Element Concentrations and Height-Percentile Status in Mongolian Children and Adolescents: A Retrospective Cross-Sectional ICP-MS Study

In this retrospective cross-sectional study, we examined associations between hair element concentrations and recorded height-percentile status in 1000 Mongolian children and adolescents aged 1–18 years. Concentrations of 26 elements were measured by inductively coupled plasma mass spectrometry. Ordinal models used 998 available outcomes, adjusted for age group and sex, with false-discovery-rate (FDR) correction. Twelve elements met FDR q < 0.05. Lead (adjusted odds ratio [aOR] 0.80, 95% confidence interval [CI] 0.70–0.92; q = 0.0046) and aluminum (aOR 0.84, 95% CI 0.73–0.96; q = 0.0317) were inversely associated with height-percentile status. With additional recorded covariates, lead remained associated (q = 0.0179), whereas aluminum did not meet the FDR criterion (q = 0.0975). Global proportional-odds assumptions were not supported; threshold-specific estimates were therefore reported. Sensitivity analyses examined age specification, measured height, age restriction, and zero-value handling. These exploratory associations in a selected clinical cohort do not establish independent elemental effects, systemic toxicant burden, or causality. Interpretation is limited by selection, residual confounding, non-harmonized growth references, and unavailable element-specific analytical validation records.