Abstract
Objectives: To examine whether sex modifies associations between whole-night and sleep-stage-specific respiratory indices and metabolic parameters in children with obstructive sleep apnea (OSA). Methods: This retrospective cross-sectional secondary analysis included a previously reported cohort of 514 children (330 boys, 184 girls) referred for suspected sleep-disordered breathing. Whole-night, rapid eye movement (REM), and non-rapid eye movement (NREM) obstructive apnea–hypopnea index (OAHI) and oxygen desaturation index (ODI) were examined in sex-stratified and pooled interaction models adjusted for age and body mass index z-score. Benjamini–Hochberg correction was applied across 30 interaction tests. Sleep architecture was also assessed. Results: After false discovery rate (FDR) correction, triglycerides (TG) were positively associated with all six respiratory indices in both sexes. Sex interactions were significant for TG with whole-night OAHI (standardized β = −0.509; 95% CI, −0.737 to −0.281) and NREM OAHI (β = −0.582; 95% CI, −0.813 to −0.350; both q < 0.001), indicating stronger associations in girls (boys minus girls). No other interactions survived FDR correction. Conclusions: Sex-related heterogeneity was confined to selected TG–OAHI associations. Independent prospective validation is needed to assess reproducibility and clinical relevance.