Current Evidence on the Effects of Endocrine-Disrupting Chemicals (EDCs) on Bone Growth and Health

Endocrine-disrupting chemicals (EDCs) are a heterogeneous group of natural and man-made chemicals from environmental sources that mimic natural hormones. They can have adverse effects on the morphology, physiology, growth, and development of different organs and systems, among these bone health can be affected too. EDCs work as agonists or antagonists on hormonal receptors in hormone-sensitive cells, influence gene expression by epigenetic mechanisms, stimulate or inhibit cell maturation, and affect the synthesis and metabolism of hormones. This review aims to summarize current evidence on the effects of exposure to EDCs on bone from early gestational to birth and long-term adverse effects. Single and mixtures of endocrine-disrupting chemicals can disrupt bone structure by modifying differentiation, increasing osteoclast activity, inhibiting pre-osteoblasts differentiation into mature osteoblasts and osteocytes, inducing changes in signaling pathways downstream of receptors, and ultimately remodeling and modifying the equilibrium between bone resorption and formation leading to increased bone resorption, morphological, and functional changes in bone maturation. EDCs can affect the IGF system, alkaline phosphatase, and osteocalcin gene expression. Findings are relative to both in vitro and in vivo studies. Studies have shown that prenatal exposure to EDCs leads to growth retardation, delayed ossification, and changes in bone length and size and in bone geometry with a lowering of bone mineral density and area-adjusted bone mineral content. Current knowledge on bone health, growth, mineral content, and development from molecular to clinical findings highlights how endocrine-disrupting chemicals can negatively affect these processes. Mechanisms, however, are not fully understood and need further investigation.