Long-term exposure to air pollutants increases the risk of dysmenorrhea in women

Dysmenorrhea, which is frequent severe painful cramps during menstruation due to abnormal contractions of the uterus, is the most common of all gynecological disorders. It affects between 16% and 91% of girls and women of childbearing age, of whom 2% to 29% have symptoms severe enough to restrict their daily activity.

Today, for the first time, researchers from China Medical University Hospital in Taiwan have shown that long-term exposure to air pollutants such as nitrogen and carbon oxides and fine particles significantly increases the risk of developing dysmenorrhea. Based on long-term air quality and public health data from national databases, they show that the risk of developing dysmenorrhea over a 13-year period (2000-2013) was up to 33 times higher among Taiwanese women and girls who lived in areas with the highest levels of air pollutants compared to their peers exposed to lower levels of pollutants. These results were recently published in the open access journal Frontiers in public health.

A common debilitating disorder with no known cure

Dysmenorrhea can be due to hormonal imbalances or underlying gynecological conditions such as endometriosis, pelvic inflammatory disease, ectopic pregnancy, or tumors of the pelvic cavity. Symptoms often last a lifetime: they include cramps and pain in the lower abdomen, pain in the lower back and legs, nausea and vomiting, diarrhea, fainting, weakness, fatigue and headaches. In addition to reducing the quality of life, dysmenorrhea also has a major socio-economic impact, as women with dysmenorrhea may be temporarily unable to work, attend school, or engage in leisure activities. . Dysmenorrhea has no known cure, but its symptoms can be treated with anti-inflammatory drugs and hormonal contraceptives.

“Research has already shown that women who smoke or drink alcohol during their period, or who are overweight, or have their first period very young, are at greater risk of dysmenorrhea. Women who have never been pregnant are also known to be at higher risk. But here we demonstrate for the first time another important risk factor for developing dysmenorrhea: air quality, especially long-term exposure to pollution. We don’t yet know the underlying mechanism, but emotional stress in women exposed to air pollutants, or higher average levels of hormone-like prostaglandins in their bodies could be part of the answer, ”says one. by the authors, Professor Chung Y. Hsu of the College of Medicine, China Medical University, Taichung, Taiwan.

The authors, led by Professor Chia-Hung Kao, director of the Department of Nuclear Medicine and the Positron Emission Tomography (PET) Center at China Medical University, studied the anonymized health measurements of a total of 296,078 women and girls (about 1.3% of the total population) between 16 and 55 years old. These data are from the Taiwan Longitudinal Health Insurance Database from 2000 (LHID 2000), a representative subsample of the Taiwan National Health Insurance Database.

The study sample included exclusively women and girls with no recorded history of dysmenorrhea prior to 2000. The authors looked for a long-term association between the risk of dysmenorrhea and air quality, particularly exposure. average over the years to atmospheric pollutants – nitrogen oxide (NO_X), nitrogen monoxide (NO), nitrogen dioxide (NO₂), carbon monoxide (CO) and particles less than 2.5 m in diameter (“PM2.5”) – obtained from the “Taiwan Air Quality Monitoring Database” (TAQMD) of the Environmental Protection Agency.

Air pollutants are a major new risk factor

They found that from 2000 to 2013, 4.2% of women and girls in the study sample were first diagnosed with dysmenorrhea. As predicted in previous studies, younger women, women with lower income and living in more urbanized areas tended to have a higher risk of developing dysmenorrhea during the study period. More importantly, the “risk ratio” (that is, the risk specific to age and year) of developing dysmenorrhea was multiplied by 16.7 to 33.1 for women and men. daughters of the 25% of the areas with the highest annual exposure to air pollutants, compared to those of the 25% of the least exposed areas. NO_X, NERD₂The levels of, CO and PM2.5 each contributed separately to the increased risk, but the largest individual effect came from long-term exposure to elevated PM2.5.

“Our results study demonstrates the major impact of air quality on human health in general, here specifically on the risk of dysmenorrhea in women and girls. It is a clear illustration of the need for actions by government agencies and citizens to reduce the air. pollution, in order to improve human health, ”concludes Professor Hsu.