Exploring the relationship between microplastic exposure and bone health.

The ubiquity of microplastics and nanoplastics (or microplastic and nanoplastic particles, collectively MNPs) in the modern environment has led to the detection of polymer particles and polymer-associated chemicals repeatedly within human tissues and fluids, inevitably raising concern for long-term effects on organ systems, including the skeleton. Accumulated evidence over the past decade implicates MNPs and plastic-associated endocrine-disrupting chemicals (EDCs), such as phthalates and bisphenols, in pathways central to bone homeostasis and in direct cellular toxicity to bone cells. Epidemiological data that directly link MNP burden to osteoporosis or fractures in humans remain scarce; by contrast, multiple human biomonitoring studies of phthalates, bisphenol analogs, and other EDCs report associations with lower bone mineral density or with surrogate markers of bone turnover. Preclinical studies suggest plausible causal routes by which MNPs could affect bone strength. This narrative review synthesizes current human-relevant data on exposure, tissue presence, epidemiology, and mechanisms; highlights critical gaps; and proposes priorities for research and clinical surveillance.