The Invisible Factor Weakening America's Bones

Researchers have identified environmental pollution as an emerging risk factor for osteoporosis, particularly affecting women over 50, adding to traditional risk factors such as poor diet, lack of exercise, and smoking. Scientists have linked various pollutants, including air particulates, heavy metals, and synthetic chemicals, to accelerated bone deterioration and increased fracture risks.

“Air pollution is a neglected risk factor for osteoporosis because for years we’ve focused on things like lifestyle factors, hormones, and genetics,” says Tuan Van Nguyen, professor of epidemiology at the University of New South Wales, Australia.

The condition affects approximately 10 million Americans over age 50, with women comprising 80% of cases. Post-menopausal women face particular vulnerability due to decreased estrogen levels. As a result, more than one in every two women over 50 is likely to experience an osteoporotic fracture in their senior years.

A 2021 meta-analysis examining data from over 9 million patients revealed that air pollution exposure increases osteoporosis and hip fracture risks. One study found that each increment in fine particulate matter pollution (PM2.5) comparable to the difference between rural and urban American environments nearly doubled osteoporosis risk.

Environmental epidemiologist Diddier Prada from the Icahn School of Medicine at Mount Sinai notes that “even low levels of contaminants might have an effect on bones.” His 2017 research published in the Lancet demonstrated that PM2.5 concentrations below Environmental Protection Agency standards corresponded with increased hospital admissions for bone fractures.

Nitrogen oxides from fossil fuel combustion and vehicle exhaust present another air pollution threat to bone health. Prada’s 2023 study of over 9,000 post-menopausal women in the United States found that residents of areas with higher nitrogen oxide pollution experienced accelerated bone density loss. In the lumbar spine region, this pollution-related deterioration occurred at nearly twice the rate of natural aging.

Industrial heavy metals pose additional risks to bone health through food, water, and air exposure. The historical case of Itai-itai disease in Japan’s Jinzu River basin demonstrated cadmium’s severe impact on bone health, particularly affecting women who consumed contaminated rice. It took decades for scientists to pin down the cause - a diet based on rice grown in fields contaminated by cadmium from a local mine.

Today, rice from polluted soils is still the largest contributor to dietary cadmium intake in Asia (the most contaminated food sources in the United States are sunflower seeds, boiled spinach and potato chips). Once in the body, lead and cadmium accumulate in our bones — which Van Nguyen calls the “toxic waste dump” for such minerals.

Contemporary research continues to highlight these concerns, with a 2023 meta-analysis of five studies showing that cadmium exposure nearly doubled osteoporosis risk among post-menopausal women.

Modern synthetic chemicals known as PFAS (polyfluoroalkyl and perfluoroalkyl substances) have emerged as another bone health concern. Research from Ronneby, Sweden, where drinking water contained PFAS levels exceeding national standards by 115 times, revealed increased hip fracture risks. Yiyi Xu, an epidemiologist at the University of Gothenburg, found that consuming highly contaminated water raised hip fracture risk by 12% compared to less exposed populations.

Scientists have identified several mechanisms through which pollution affects bone health. Van Nguyen explains that pollution exposure triggers chronic inflammation, potentially disrupting bone metabolism. A 2024 study revealed that PM2.5 exposure leads to increased production of osteoclasts - bone-degrading cells - and lower production of osteoblasts - bone-forming cells.

Pollution may also compromise vitamin D levels through multiple pathways. Van Nguyen says vitamin deficiency “is associated with low bone mineral density and an increased risk of fracture.” That could be because people living in areas of high pollution may feel discouraged from engaging in outdoor activity, resulting in lesser exposure to vitamin D from sunlight. 

Beyond discouraging outdoor activity, certain PM2.5 compounds can accelerate vitamin D breakdown. Xu notes that PFAS may bind to vitamin D receptors in the body, “which means that your body cannot efficiently synthesize or absorb the vitamin, and then it can influence your bone health.” These chemicals also disrupt the endocrine system’s hormone production and regulation, particularly affecting estrogen levels crucial for bone health.

“Forever chemicals” have been found to disrupt the endocrine system and its “production and regulation of hormones, like estrogens, which in turn affect bone metabolism,” Van Nguyen says.

Recent research indicates that PFAS promotes fat cell accumulation within the bone marrow, potentially contributing to osteoporosis development. While pollution’s effects on bone health may be less pronounced than lifestyle factors like smoking, Prada emphasizes that pollution exposure often lies beyond individual control.

“Increase your physical activity, try to do some weight-bearing,” and, of course, eat healthily, “avoid smoking, avoid alcohol,” he says.

The widespread nature of these pollutants raises particular concern. PFAS, found in various consumer products from makeup removers to guitar strings, are detectable in 95% of Americans’ blood samples. Common foods in the United States, including sunflower seeds, boiled spinach, and potato chips, can contain significant cadmium levels.

As Western populations age and climate change intensifies pollution through events like wildfires and flooding, maintaining bone health requires increased vigilance. Health experts recommend focusing on controllable factors through regular weight-bearing exercise, balanced nutrition, and avoiding smoking and excessive alcohol consumption.

While definitive proof of causation remains challenging due to ethical constraints on controlled human trials, animal studies support the pollution-osteoporosis connection. Recent research demonstrated bone loss in mice exposed to cadmium, adding to the growing body of evidence linking environmental pollutants to compromised bone health.