A new study reports a worrying link between higher levels of air pollution and faster bone loss due to osteoporosis, a chronic skeletal condition that makes bones more fragile and prone to breaking.
The risk of osteoporosis increases with age and is particularly common in postmenopausal women. Here, data from a diverse group of 9,041 postmenopausal women were collected over 6 years, with researchers looking specifically at bone mineral density: an indirect indicator of osteoporosis and fracture risk.
Using home addresses for estimates of nitric oxide, nitrogen dioxide, sulfur dioxide and PM10 particulate matter (pollution smaller than 10 micrometers, the diameter of a red blood cell), the researchers found that as pollution increased, mineral density bone decreased. all bony areas of the body – including the neck, spine and hips.
“Our findings confirm that poor air quality can be a risk factor for bone loss, independent of socioeconomic or demographic factors,” says biomedical scientist Diddier Prada of Columbia University in New York.
Previous studies have shown an association between worse air pollution and a higher risk of bone fractures, as well as greater bone loss over time. This research adds data on postmenopausal women in particular and on different mixes of air pollution.
In particular, Prada and his colleagues highlighted the link between nitrogen and the spine. A 10% jump in this type of pollution over 3 years was associated with an average annual loss of 1.22% in lumbar spine bone mineral density, twice the amount the team calculated based on normal aging.
According to the researchers, this is likely due to the death of bone cells caused by mechanisms such as oxidative stress, in which toxic molecules from the environment cause damage to the body.
“For the first time, we have evidence that nitrogen oxides, in particular, are major contributors to bone damage and that the lumbar spine is one of the most susceptible sites for this damage,” says Prada.
The study isn’t enough on its own to prove a causal relationship — that air pollution is definitely leading to bone loss — but considering the mass of research that’s now brewing, it seems like an increasingly plausible hypothesis.
It is also worth bearing in mind that although this particular study looked at postmenopausal women, the participants involved covered a wide range of ethnic groups, locations, lifestyles and socioeconomic backgrounds, making it more likely that pollution levels would be , in fact, the underlying cause. of bone loss.
Researchers want to see more efforts in reducing air pollution – traffic is a big producer of nitrogen oxides, for example – and in detecting people who may be more vulnerable to it (including those with osteoporosis).
“Improvements in exposure to air pollution, particularly nitrogen oxides, will reduce bone damage in postmenopausal women, prevent bone fractures, and reduce health costs associated with osteoporosis among postmenopausal women,” says epigeneticist Andrea Baccarelli of Columbia University.
The research was published in eClinicalMedicine.