Michael Monostra , 2025-05-09 13:37:00
Key takeaways:
- Nitrogen oxide may affect plasma levels of a certain metabolite that may lead to lower lumbar spine BMD for postmenopausal women.
- More research using a larger sample size is needed to validate the findings.
Air pollution could lead to changes in certain metabolites that may be partially responsible for bone mineral density loss in postmenopausal women, according to findings published in the Journal of Bone and Mineral Research.
Prior studies have observed a link between air pollution, reduced BMD and increased fracture risk, according to Diddier Prada, MD, PhD, assistant professor of population health science and policy and environmental health at the Icahn School of Medicine at Mount Sinai. However, Prada said questions still remain regarding mechanisms. In a study using data from the Women’s Health Initiative, researchers that long-term exposure found nitrogen monoxide, nitrogen dioxide and sulfur dioxide were associated with multiple plasma metabolite concentrations. One of those metabolites, C38:4 phosphatidylethanolamine, was found to be a partial mediator of the association between nitrogen oxide and lumbar spine BMD.
“C38:4 phosphatidylethanolamine is a phospholipid that is in the pathway between the exposure and [bone] damage,” Prada told Healio. “It is showing us potential pathways that we could do some intervention, modifying this pathway to lead us to improved health in aging people.”
The analysis included 192 postmenopausal women who enrolled in the Women’s Health Initiative between 1993 and 1998 and had BMD and air pollution levels available (mean age, 66.6 years). Mean concentrations of air pollution were obtained from the residential address of each participant using U.S. Environmental Protection Agency air quality system data. Metabolomic data were obtained from plasma samples. BMD was assessed in a DXA scan at baseline, 1, 3 and 6 years of follow-up.
Across a 1- 3- and 5-year averaging windows, nitrogen oxide was associated with the level of 19 shared metabolites, whereas nitrogen dioxide was linked to 26 shared metabolites. Sulfur dioxide was associated with three shared metabolites across both a 3- and 5-year window. Particulate matter of 10 µm or less was not associated with any plasma metabolites.
Of metabolites associated with air pollution, C38:4 phosphatidylethanolamine, C38:5 phosphatidylethanolamine, taurine and lactose were associated with lower lumbar spine BMD. Inosine was associated with lower total hip and femoral neck BMD, whereas cytidine monophosphate was tied to a lower total hip BMD.
In mediation modeling, C38:4 phosphatidylethanolamine was found to account for 31% of the association between nitrogen oxide and lower lumbar spine BMD during a 1-year averaging period (P = .032).
Though Prada described the finding as exciting and novel, he said the study had a small sample of participants and more research is needed to validate the findings.
The study should also be used to raise awareness about the adverse health outcomes associated with air pollution, Prada said.
“We need to continue highlighting that air pollution needs to be reduced, that we need clean air in urban spaces and some rural spaces that have high levels of pollutants, because air pollution does not affect only bones,” Prada said. “We know there are effects on the heart. We know there are effects on systemic inflammation affecting brain function. We need to be insistent that we need cleaner air, particularly for those who are more vulnerable.”
For more information:
Diddier Prada, MD, PhD, can be reached at diddier.prada@mountsinai.org.