Jan. 3 (UPI) -- Air pollution has obvious effects on health, and it has been linked with everything from increased risk for lung cancer to stroke, among other serious complications.
Now, however, a study published Friday by JAMA Network Open has found pollution in the air may have a less obvious, but no less serious, impact on health bone density and strength.
The results showed that exposure to ambient air pollution, particularly to fine particles, was associated with lower levels of bone mass, the authors said.
"This study contributes to the limited and inconclusive literature on air pollution and bone health," co-author Otavio T. Ranzani, researcher at the Barcelona Institute for Global Health, said in a statement.
The findings demonstrated that "inhalation of polluting particles could lead to bone mass loss through the oxidative stress and inflammation caused by air pollution," he added.
Reduced bone mass has been associated with significant health complications, including osteoporosis. As many as 55 percent of Americans 50 years of age and older -- or some 44 million people -- have osteoporosis or some degree of reduced bone density, according to the International Osteoporosis Foundation.
Ranzani and colleagues analyzed the association between air pollution and bone health in more than 3,700 people from 28 villages outside the city of Hyberabad, in southern India. The authors used a locally-developed model to estimate outdoor exposure to air pollution by fine particulate matter -- suspended micro-particles with a diameter of 2.5 μm or less -- and black carbon.
Study participants also filled out a questionnaire on the type of fuel they used for cooking, as cooking fuel is a common source of air pollution around the world. The authors linked this information with participants' bone health at the lumbar spine and the left hip, which they assessed using a special type of radiography called dual-energy x-ray absorptiometry that measures bone density.
Annual average exposure to ambient PM2.5 was 32.8 μg/m3, far above the 10 μg/m3 level recommended by the World Health Organization, and average black carbon exposure was 2.5 μg/m3. In all, a 3 μg/m3 increase in PM2.5 exposure was associated with 0.57 g loss in bone mineral content in the spine and 0.13 g loss in the hip.
In all, 58 percent of study participants reported using biomass fuel for cooking, but the authors found no correlation with its use and bone health.
Although the new study is not the first to link bone health and air pollution exposure, the results of earlier research have been inconclusive.
"Our findings add to a growing body of evidence that indicates that particulate air pollution is relevant for bone health across a wide range of air pollution levels, including levels found in high income and low and medium income countries," study coordinator Cathryn Tonne said.