KUALA LUMPUR, July 28 – Women with a history of endometriosis had higher concentrations of cadmium in their urine compared to those without that diagnosis, according to a Michigan State University (MSU) study that suggests the toxic metal could be linked to the development of endometriosis.
Affecting one in 10 reproductive-age women, endometriosis is a gynaecologic condition in which tissue that looks like the lining of the uterus, or womb, appears outside the uterus.
Those with endometriosis can experience chronic, painful, and debilitating symptoms, which can interfere with all aspects of life, including daily activity, work productivity, school performance, and personal relationships.
“Despite the adverse impact of endometriosis on quality of life, it remains an understudied condition,” said Kristen Upson, assistant professor in the Department of Epidemiology and Biostatistics at the MSU College of Human Medicine and senior author of the study.
Cadmium is a toxic metal and a “metalloestrogen”, meaning it can act like the hormone oestrogen. In the US, people are commonly exposed to cadmium by breathing in cigarette smoke and eating contaminated food like spinach and lettuce.
“By looking at environmental risk factors such as metal cadmium, we are moving the needle closer to understanding risk factors for this condition,” said the study’s first author, Mandy Hall, a data analyst in the MSU Department of Epidemiology and Biostatistics, in a statement.
While this is not the first study exploring a potential link between cadmium and endometriosis, the researchers said it’s the largest study to look at cadmium measured in urine, which reflects long-term exposure between 10 and 30 years.
For their study, researchers used data from the National Health and Nutrition Examination Survey (NHANES), a national study representative of the US population between 1999 and 2006.
Out of the survey’s more than 41,000 participants, the researchers limited their study population to those 20 to 54 years of age with information on endometriosis diagnosis.
The researchers then analysed the data, dividing the cadmium levels into four classes, or quartiles, with the first quartile being the lowest exposure and the fourth being the largest exposure.
They found that participants in the second and third quartiles were twice as likely to have been diagnosed with endometriosis than those in the first quartile.
The data also suggests a 60 per cent increased prevalence of endometriosis based on urinary cadmium concentrations in the fourth quartile.
“The findings are interesting given that cadmium can act like the hormone oestrogen, and this hormone is central to the development of endometriosis,” Hall said, adding that further studies are needed to confirm their findings.