Air pollution may impact bone health. Investigators have analyzed data in a new study in Lancet Planetary Health looking at the relationship between air pollution and the risk for weakening bones. The analysis looked at two studies, one that tracked hospital admissions among nearly 10 million Medicare recipients in the Northeast over eight years. The other looked at levels of parathyroid hormone, which aids bone health, in 700 middle-aged low-income men in Boston. They found that the risk for bone fractures among people over 65 increased steadily as levels of air pollution went up. People living in locations with higher levels of air pollution, especially middle-aged men, were also found to have had lower levels of bone mineral density. The researchers compare these results to secondhand smoke, detailing that the ill effects of smoking, such as cancer, cardiovascular disease, and bone mineral density loss, can also be caused by air pollution.