Phthalate exposure and osteoporosis: NHANES associations and integrative in silico prioritization of candidate molecular targets.

BACKGROUND

Phthalates are ubiquitous endocrine-disrupting chemicals, but population-level evidence linking urinary phthalate burden with osteoporosis and the molecular context of these associations remains incomplete.

METHODS

We analyzed 8273 participants from the 2003-2010 National Health and Nutrition Examination Survey and integrated exposure-outcome modeling with public transcriptomics, target prediction, weighted gene co-expression network analysis, machine learning, immune-infiltration analysis, single-cell transcriptomics, cell-cell communication, pseudotime analysis, pathway scoring, and molecular docking.

RESULTS

Among 8273 participants, 939 met the osteoporosis definition. In the fully adjusted model, the standardized overall phthalate exposure index was associated with higher odds of osteoporosis (OR 1.38, 95% CI 1.28-1.48; P < 0.001). Weighted osteoporosis prevalence increased from 8.7% in the lowest exposure quartile to 16.4% in the highest, and higher exposure was also associated with lower femoral-neck and lumbar-spine bone mineral density. Integrative computational analyses prioritized CXCR4, CEBPB, CD44, YAP1, SPP1, IL6, and MMP9 within inflammation, osteoclast differentiation, and extracellular-matrix pathways. Immune and single-cell analyses localized these candidate targets to osteoporosis-associated macrophage, osteoclast, osteoblast, endothelial, and stromal states. Docking predicted favorable structural compatibility for MEHP-CXCR4 (-8.6 kcal/mol), MBP-CEBPB (-7.9 kcal/mol), and MECPP-YAP1 (-7.4 kcal/mol).

CONCLUSION

Higher urinary phthalate burden was associated with osteoporosis-related outcomes, while integrative in silico analyses prioritized candidate molecular and cellular contexts for future experimental testing. These findings do not establish a phthalate-induced causal mechanism.