Researchers found men, women and children who were exposed to phthalates (endocrine-disrupting chemicals found in plastics and some hygiene products) tended to have lower blood testosterone levels.
Testosterone is the main sex hormone in men, but is involved in a number of processes in both sexes such as the strength of brain function, the Endocrine Society reported. Over the past 50 years researchers have identified a trend of declining testosterone in men and an increase in related health issues.
Past animal studies have shown some phthalates block the effects of testosterone on the body. Researchers worked to identify whether the commonly used chemicals had a similar effect in human models.
"We found evidence reduced levels of circulating testosterone were associated with increased phthalate exposure in several key populations, including boys ages 6-12, and men and women ages 40 [to] 60," said one of the study's authors, John D. Meeker, MS, ScD, of the University of Michigan School of Public Health in Ann Arbor, MI. "This may have important public health implications, since low testosterone levels in young boys can negatively impact reproductive development, and in middle age can impair sexual function, libido, energy, cognitive function and bone health in men and women."
The study looked at phthalate exposure and testosterone level in 2,208 participants of the U.S. National Health and Nutrition Examination Survey, 2011-2012. To make their findings the team analyzed urine samples to measure the concentrations of 13 substances left behind when the body absorbs phthalates.
The team found an inverse relationship between phthalate exposure and testosterone levels in people across many age groups.
"While the study's cross-sectional design limit the conclusions we can draw, our results support the hypothesis that environmental exposure to endocrine-disrupting chemicals such as phthalates could be contributing to the trend of declining testosterone and related disorders," Meeker said. "With mounting evidence for adverse health effects, individuals and policymakers alike may want to take steps to limit human exposure to the degree possible."
The findings were published in the Endocrine Society'sJournal of Clinical Endocrinology & Metabolism (JCEM).
