Women with increased levels of cadmium – a metal commonly found in foods such as kidneys, liver and shellfish as well as tobacco – also had an increased risk of endometrial cancer, found a five-year observational study by the University of Missouri.
It's an observation the researchers hope could lead to new treatments or interventions to prevent the fourth most common cancer in women. More than 31,000 new cases of endometrial cancer are expected to be diagnosed in 2017.
"Cadmium is an oestrogen-mimicking chemical, meaning it imitates oestrogen and its effects on the body," said lead author Dr Jane McElroy, associate professor in the department of family and community medicine at the MU School of Medicine. "Endometrial cancer has been associated with oestrogen exposure. Because cadmium mimics oestrogen, it may lead to an increased growth of the endometrium, contributing to an increased risk of endometrial cancer."
The research team partnered with cancer registries in Missouri, Arkansas and Iowa to identify cases of endometrial cancer. The team enrolled 631 women with a history of endometrial cancer in the study and 879 women without a history of the cancer to serve as a control group. The participants were asked to complete a survey of more than 200 questions about risk factors potentially associated with endometrial cancer. Once they completed the questionnaire, participants were sent a kit to collect urine and saliva samples. Through tests conducted at the MU Research Reactor, the samples were analysed for cadmium levels.
"When comparing the cadmium levels of the individuals with endometrial cancer to the control group, we found a statistically significant increased risk of the cancer associated with a woman's cadmium levels," McElroy said. "We found the rate of endometrial cancer incidence increased by 22% in individuals with increased cadmium levels."
While more research is needed to better understand the risks associated with cadmium, researchers say there are steps individuals can take to limit their cadmium-associated cancer risks.
"We all have cadmium present in our kidneys and livers, but smoking has been shown to more than double a person's cadmium exposure," McElroy said. "Also, we recommend being attentive to your diet, as certain foods such as shellfish, kidney and liver can contain high levels of cadmium. You don't necessarily need to cut these from your diet, but eat them in moderation. This is especially true if women have a predisposition to endometrial cancer, such as a family history, diabetes or obesity."
Abstract
Estrogen-mimicking chemicals, such as cadmium, may be associated with increased susceptibility to hormone-dependent cancers, though supporting data are sparse, particularly for endometrial cancer. The Health and Environmental Exposure Research (HEER) study worked with the Arkansas Central Cancer Registry, Iowa Cancer Registry and Missouri Cancer Registry to obtain names of women diagnosed with endometrial cancer who were willing to be contacted for participation in our case control study. Voter registration lists from Iowa and Missouri were used to randomly select similarly aged women as represented in the case population. Participants were interviewed by telephone to obtain information on known or suspected endometrial risk factors. Urine kits were sent to participants for home collection and returned for analysis. Our case-control study consisted of 631 incident cases of endometrial cancer diagnosed from January 2010 to October 2012 and 879 age-matched population-based controls, ages 18–81 years (mean age 65 years). We quantified cadmium amounts in urine and standardized these values through creatinine adjustment. Using data from all survey completers, we developed a multivariable model for endometrial cancer. Creatinine-adjusted cadmium concentration was added to this model. Odds ratio (OR) and 95% confidence intervals (CIs) for endometrial cancer were calculated. After multivariable adjustment, higher creatinine-adjusted cadmium exposure was associated with a statistically significant increase of endometrial cancer risk (OR: 1.22; 95% CI: 1.03–1.44). Our results provide evidence that cadmium may increase the risk of endometrial cancer, possibly through estrogenic effects.
Authors
Jane A McElroy, Robin L Kruse, James Guthrie, Ronald E Gangnon, J David Robertson
[link url="https://www.sciencedaily.com/releases/2017/08/170809140154.htm"]University of Missouri-Columbia material[/link]
[link url="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0179360"]PLOS One abstract[/link]