(Reuters Health) – - Men who work with hormone-mimicking chemicals for at least 30 years have a higher risk of cancers of the lymph tissue than others, according to a long-term observational study in several European countries.
“Endocrine disruptors are chemicals that interfere with our endocrine system (hormones),” said lead author Laura Costas of the Catalan Institute of Oncology in Barcelona. Some endocrine disruptors either activate or block hormone receptors, while others can modify the production or delivery of natural hormones, she said.
“The hormone system has a delicate equilibrium and chemicals altering it may produce health problems,” Costas told Reuters Health by email.
For the new study, the authors used interviews of 2,178 people diagnosed with a lymphoma and of 2,457 similar people without the cancer between 1998 and 2004 in Spain, France, Germany, Italy, Ireland and the Czech Republic. Participants listed all of their full-time jobs that had lasted for at least one year.
Experts determined which of the occupations would likely have involved exposure to endocrine disrupting chemicals, which include pesticides, cosmetics, plastic additives and flame-retardants.
Many of the chemicals are common in everyday life, so the experts estimated which jobs would likely have led to more exposure than just the “background” level that most people experience.
“The exposure to these compounds is common in specific jobs,” Costas said. “We observed that around 15 percent of participants without cancer worked for 30 years or more in these occupations.”
“However, we did not have data on the protections that people used to avoid contact with these chemicals, which is relevant to assess their personal exposure,” she said.
Among 1,720 people with cancer, 633 had probable exposure to the chemicals, 438 had possible exposure and 588 were unlikely to have been exposed.
There was no overall association between ever having been exposed to one of the chemicals and lymphoma risk. But as exposure duration increased, risk for lymphoma increased as well.
Men who had been exposed to a hormone-disrupting chemical for more than 30 years were 32 percent more likely to develop lymphoma than those with no exposure. There was no increased risk for women, according to the results in the British Journal of Cancer.
“These are associations that merit more research in order to be confirmed in other basic and translational studies before concluding that they cause lymphoma,” Costas said.
This study supports correlation, but not necessarily causation, between exposure and lymphoma, according to Andrea C Gore, the Johnson and Johnson Centennial Professor of Pharmacy at The University of Texas at Austin, who was not part of the new research.
“Cause-and-effect between endocrine disruptors and human disease is always very difficult to establish as there are many other reasons why someone develops a disorder, and we all have unique genetic risk factors, differences in lifestyle, and other characteristics that contribute to ultimately developing a disease,” Gore told Reuters Health by email.
The effect size in the new study was relatively small, she said.
Only finding an association for men may explain why lymphomas are more common for men than women, Costas said, but endocrine-disrupting chemicals may have other impacts on women’s health.
“Occupation is only one source of exposure, but there are others, and the most common is diet,” Costas said.
The dietary impact of these compounds is still unclear, she said.
“Our results refer to exposures that happened many years ago, and luckily, work conditions and security have substantially improved over the years,” she said. “Measures of protection have been implemented, and it is important that all workers follow the guidelines to minimize exposure to these chemicals.”
SOURCE: bit.ly/1Bbrr9k British Journal of Cancer, online March 5, 2015.