Air Pollution and Osteoporosis

Abstract

Purpose of review: The purpose of this review is to provide a background of osteoporosis and air pollution, discussing increasing incidence of the disease with exposure to pollutants and the role that inflammation may play in this process.

Recent findings: Osteoporosis-related fractures are one of the most pressing challenges for the ageing global population, with significant increases in mortality known to occur after major osteoporotic fractures in the elderly population. Recent studies have established a firm correlative link between areas of high air pollution and increased risk of osteoporosis, particularly alarming given the increasingly urban global population. While the culprit pollutants and molecular mechanisms underlying this phenomenon have not yet been elucidated, initial studies suggest a role for inflammatory cascades in this phenomenon. While much more research is required to identify the most damaging air pollutants and to delineate the specific inflammatory molecular mechanisms, it is clear from the literature that shedding light on these pathways would unveil potential therapeutic targets to treat bone diseases, including osteoporosis. Major deficiencies of current animal models highlight the need for complex human in vitro models such as organ-on-a-chip technology to better understand the impact of air pollution.

Keywords: Air pollution; Bone mineral density; Inflammation; Osteoporosis.

Fig. 1

A Long-term exposure to PM10 in Italy (2013–2019 average concentration μg/m³)[48]. Risk of osteoporosis at any site in patients chronically exposed to PM10 > 30 μg/m³ and PM2.5 > 25 μg/m³. Model 1 adjusted for age, body mass index (BMI), presence of prevalent fragility fractures, family history of osteoporosis, and menopause. Model 2 adjusted for age, BMI, presence of prevalent fragility fractures, family history of osteoporosis, menopause, glucocorticoid treatment, and comorbidities. Model 3 (main model) adjusted for age, BMI, presence of prevalent fragility fractures, family history of osteoporosis, menopause, glucocorticoid treatment, comorbidities, and macro-area of residency (categorized as northern Italy, central Italy, and southern Italy). B Average PM2.5 concentrations per zipcode in the US Northeast between 2003 and 2010[43]. Spline shown for the multivariable-adjusted association between PM2·5 exposure and number of hospital admissions of Medicare enrollees per zipcode, from 2003 to 2010. Horizontal dotted line represents zero effect. C Example of nearest neighbour interpolation between measurements in Taiwan [58], with big circles standing for monitoring station and small ones for participants. A synergistic effect of CO and NOx on BMD T-score was found to be statistically significant (p = 0.001), as was a synergistic effect between SO2 and NO2 (p = 0.004)