Exposure to Environmental Chemicals and Human Bone Health; A Systematic Review and Meta-Analysis

Osteoporosis is a complex non-communicable disease characterized by low bone mineral density (BMD). Exposure to environmental factors such as air pollution and heavy metals has been linked to low BMD. This study aimed to review the emerging evidence investigating the associations between exposure to environmental chemicals and human bone mineral density or the risk of osteoporosis. A comprehensive electronic search was performed in PubMed, Web of Science, Scopus, and Embase up to March 3, 2022. Beta coefficients were extracted with 95% confidence intervals to calculate pooled mean differences for BMD in random effect models. For data synthesis, main exposure groups were identified using the Fourth National Report on Human Exposure to Environmental Chemicals, Centers for Disease Control and Prevention (CDC). Overall, 3181 records were identified. We reviewed 27 English articles with an analytical observational study design. In quantitative analysis, exposure to perfluorooctane sulfonate (PFOS) was significantly associated with low spinal BMD among women (mean difference = − 0.01 g/cm 2 , 95% CI − 0.02 to − 0.004 g/cm 2 ). Up to date, there is supportive evidence for the inverse associations of perfluoroalkyl substances (PFASs) and phthalates with BMD. The association of polycyclic aromatic hydrocarbons (PAHs) with BMD seems to vary by specific urinary PAHs and bone sites. For bisphenols and organochlorinated pesticides (OCPs), the evidence for negative associations with BMD is insufficient. For other groups, including triclosan, polychlorobiphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs), the research is controversial or scant and needs to be extended. Available high-quality evidence supports the association between exposure to some environmental chemicals and lower BMD as well as increased risk of osteoporosis.