The risk of such self-reported fibroids increased with rising levels of ozone in the atmosphere, but this link was not seen with PM2.5 or NO2, the study showed.
The findings held even after researchers controlled for other factors that could affect the outcome, including other air pollutants, economic status, access to or quality of health care, and lifestyle factors related to fibroid risk.
“It is unclear why we did not see an association with the two other pollutants,” Wesselink says. “It could be that there is a mechanism unique to ozone that is yet to be uncovered.”
For example, ozone is related to the presence of sunlight as is vitamin D, and vitamin D deficiency may be driving this link. The study did not measure vitamin D exposure.
More research is needed to confirm the findings, Wesselink says.
“Ideally, we would screen an entire population to measure development of fibroids over time so that we aren’t relying on self-reported diagnosis,” she says. This would also catch women who have no symptoms.
Not all fibroids cause symptoms, but those that do may result in heavy or painful periods, stomach and back pain, constipation, the frequent need to urinate, and pain or discomfort during sex, according to Dr. Jennifer Wu, an obstetrician-gynecologist at Lenox Hill Hospital in New York City.
Family history, hormone levels and pregnancy are known to increase the odds of developing the growths.