Osteoporosis affects nearly 200 million women worldwide, with postmenopausal women at a higher risk. One in two women over 50 suffers a bone fracture due to osteoporosis.
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Air pollution has been linked to many health-related problems and diseases in the past, such as cardiovascular diseases, and respiratory problems, and now, in a recently published study, air pollution has been linked to bone damage.
Scientists in the US from Columbia University, in a study, have found that long-term exposure to air pollutants might lead to bone damage in elderly or postmenopausal women.
Image Credits: University Diagnostic Medical imaging
According to the study, air pollutants, especially nitrogen oxides, have a major contribution to bone damage. Also, one of the most susceptible sites for bone damage was found to be the lumber spine.
Post-Menopausal Women Recruitment
For the study, a large number of ethnically diverse, postmenopausal women were analyzed.
The study was published in eClinicalMedicine. This is the first study to explore the association between bone mineral density (BMD) and air pollutants, especially in postmenopausal women. Furthermore, this is the first to explore the effects of air pollution mixture on bone outcomes.
The study has been prepared based on the data collected from the Women’s Health Initiative (WHI). WHI recruited ethnically diverse, 161,808 postmenopausal women from around 40 clinical centers across the nation. These women were recruited between 1st October 1993 and 21st December 1998. All of the recruited women were from the ages of 50-79 years old at the time of enrollment.
The participants in general had low physical activity, consumed less than seven alcohol servings per week, had a modest income, and were never smokers.
The bone mineral density was studied during different clinical visits after enrollment. These visits were recorded in years 1, year 3, year 6, and year 9. Participants without any estimated pollution were excluded from the study.
Major Sources of Air Pollutants
The effects of NO and NO2 on bone health, especially the lumber spine were twice as damaging to the concerned area as normal aging. Most are in the air, which is anthropometric and is generated by stationary or mobile sources, such as automobiles, buses, trucks, factories, construction sites, refineries, and industries that use cleaning solvents.
Emissions from electrical generation plants, and car and truck exhaust is the major source of NOx, which is an air pollutant that leads to bone damage.
Findings
All four types of air pollutants were observed and estimated. These are PM10, NO, NO2, and SO. Their exposures were estimated based on the participant’s home addresses. There were three clinical centers for the study;
- Birmingham, Alabama
- Pittsburgh, Pennsylvania
- Tuscon, Arizona
There was also a satellite clinic that was chosen for maximum racial diversity. It was located in Phoenix, Arizona.
The data found that the air pollutants NO and No2 had the highest correlations with correlation coefficients of 0.83 in year 1, 0.85 in year three, and 0.86 in year 5.
The team measured the bone mineral density using dual X-ray absorptiometry at enrollment and the follow-up in years 1, 3, and 6.
The extent of the effects of nitrogen oxides on the BMI of the lumbar spine was estimated at a 1.22 percent annual reduction, which according to the researchers is double the annual effects of age on any of the evaluated anatomical sites.
These are believed to occur due to bone cell death which can be caused by oxidative damage or some other means.
Future Investigations
Investigators have acknowledged that further research is needed for the investigation of mechanisms that are underlying the association between bone damage and air pollution.
Diddier Prada, Associate Research Scientist, Department of Environmental Health Sciences, Columbia Mailman School of Public Health stated that the findings confirm that poor air health quality might be a risk factor for bone loss, irrespective of other factors. Furthermore, she added that this is the first evidence that particularly nitrogen oxides are the major contributors to bone damage and one of the most susceptible sites for this damage is the lumbar spine.
Andrea Baccarelli, varsity, the lead author of the study, said that improvements in exposure to air pollution especially nitrogen oxides can lead to the reduction of bone damage in postmenopausal women, also, prevent bone fractures which can reduce the burden of health costs associated with osteoporosis among postmenopausal women.
