Everyday chemical exposure linked to earlier menopause

A new study from Washington University School of Medicine found that women who had high levels of certain chemicals in their bodies experienced menopause two to four years earlier than women with lower levels of the chemicals.

The study is the first to broadly explore the association between menopause and individual chemicals on a large scale, according to a news release. Researchers looked at blood and urine levels of 111 chemicals that are suspected of interfering with natural hormone production and distribution.

"Chemicals linked to earlier menopause may lead to an early decline in ovarian function, and our results suggest we as a society should be concerned," senior author Dr. Amber Cooper, an assistant professor of obstetrics and gynecology, said in a news release.

Data analyzed from 1,442 menopausal women was nationally representative of a population of almost 9 million menopausal women, according to the news release. Researchers used information collected from 1999-2008 as part of the Centers for Disease Control and Prevention’s (CDC) National Health and Nutrition Examination Survey. The survey included 31,575 people.

The menopausal women included in the data had an average age of 61, and none used estrogen-replacement therapies or had ovary-removal surgery. All had been been tested for levels of endocrine-disrupting chemicals.

Researchers analyzed the women’s blood and urine samples for exposures to 111 mostly man-made chemicals, including known reproductive toxins and those that take more than a year to break down. These chemicals included phthalates, which are found in plastics, common household items, pharmaceuticals, and personal care products; phytoestrogens, plant-derived estrogens; and dioxins/furans, industrial combustion byproducts.

According to the news release, a decline in ovarian function can adversely affect fertility and lead to earlier development of heart disease, osteoporosis and other health problems. The chemicals had previously been linked to certain cancers, metabolic syndrome, and early puberty in younger females.

"Many of these chemical exposures are beyond our control because they are in the soil, water and air," Cooper said. "But we can educate ourselves about our day-to-day chemical exposures and become more aware of the plastics and other household products we use."

To avoid chemical exposure, Cooper recommended microwaving food in glass or paper containers rather than in plastic. It’s also important to study ingredients in cosmetics, personal care products, and food packaging that are used daily, she added. While many of the chemicals included in the study are banned in the U.S., they are still produced globally and are pervasive in their environment, researchers noted.

Fifteen of the chemicals— nine polychlorinated biphenyls (PCBs), three pesticides, two phthalates, and a furan (toxic chemical)— were flagged for closer evaluation because they were significantly associated with earlier ages of menopause and potentially have detrimental effects on ovarian function.

"Earlier menopause can alter the quality of a woman's life and has profound implications for fertility, health and our society," Cooper said in the  news release. "Understanding how the environment affects health is complex. This study doesn't prove causation, but the associations raise a red flag and support the need for future research."

The study was published Jan. 28 in the journal PLOS ONE.