Air pollution speeds up bone loss from osteoporosis: Study

Increased levels of air pollutants such as nitrous oxides are associated with bone damage among postmenopausal women, according to a study.

Scientists at Columbia University Mailman School of Public Health, US, found that the effects were most evident on the lumbar spine, with nitrous oxides (NO) twice as damaging to the area as in normal ageing.

Previous studies on individual pollutants have suggested adverse effects on bone mineral density, osteoporosis risk, and fractures in older individuals.

The latest research, published in the journal eClinicalMedicine, is the first to explore the connection between air pollution and bone mineral density specifically in postmenopausal women, and the first to explore the effects of air pollution mixtures on bone outcomes.

The researchers analysed data collected through the Women’s Health Initiative study, an ethnically diverse group of 161,808 (over 1.6 lakh) postmenopausal women.

They estimated air pollution (PM10, NO, NO2, and SO2) exposures based on participants’ home addresses.

The team used dual-energy X-ray absorptiometry to measure bone mineral density (BMD) at enrollment and at follow-up at year one, year three, and year six.

The magnitude of the effects of nitrogen oxides on lumbar spine BMD would amount to 1.22 per cent annual reductions — nearly double the annual effects of age on any of the anatomical sites evaluated, the researchers said.

These effects are believed to happen through bone cell death by way of oxidative damage and other mechanisms, they said.

”Our findings confirm that poor air quality may be a risk factor for bone loss, independent of socioeconomic or demographic factors,” said study first author Diddier Prada, an associate research scientist at Columbia Mailman School of Public Health.

”For the first time, we have evidence that nitrogen oxides, in particular, are a major contributor to bone damage and that the lumbar spine is one of the most susceptible sites of this damage,” Prada said.

Study lead author Andrea Baccarelli, from Columbia Mailman School of Public Health, noted that improvements in air pollution exposure, particularly nitrogen oxides, will reduce bone damage in postmenopausal women, prevent bone fractures, and reduce the health cost burden associated with osteoporosis among postmenopausal women ”Further efforts should focus on detecting those at higher risk of air pollution-related bone damage,” Baccarelli said.

Car and truck exhaust is a major source of nitrous oxides, as are the emissions from electrical power generation plants.

Osteoporosis impacts women more than men, with 80 per cent of the estimated 10 million Americans with osteoporosis being women, the researchers said.

Postmenopausal women are at higher risk, with one in two women over 50 experiencing a bone fracture because of osteoporosis, they said.