Summary: Phthalate exposure is linked to sleep disruptions and insomnia in menopausal women.

Source: NAMS

For menopausal women who have difficulty sleeping, it might be because of chemicals in the environment. A new study based on data from the Midlife Women’s Health Study suggests that exposure to various chemicals, such as phthalates, found in hundreds of products used daily, is associated with sleep disruptions in midlife women. Study results are published online today in Menopause.

Up to 60% of women in the menopause transition experience sleep difficulties. Women who have trouble falling asleep are at greater risk of developing persistent depression that can lead to worse health outcomes, may require more medical care, and increase absenteeism.

Earlier studies have shown that such sleep disruption is the result of decreasing hormone levels. Exposure to endocrine-disrupting chemicals (EDCs), however, is one largely unexplored area that may help to explain the increased prevalence of sleep difficulties in midlife women. Phthalates are common EDCs that are found in industrial plasticizers and chemical stabilizers. Phthalates increase the performance of everything from food packaging and clothing to cosmetics and children’s toys. Personal care products, in particular, represent a major area of exposure.

Although everyone is exposed to phthalates, they appear to concentrate more in women than men. A previous study suggested that increased exposure to phthalates from personal care products significantly increased the risk of hot flashes. Other studies have demonstrated associations between phthalate exposure and the likelihood of waking up at night, as well as the risk of suffering from depression.

Since phthalates are known to modulate the hormones associated with sleep and depression, researchers in this latest study surmised that they may be directly or indirectly associated with sleep in midlife women. This study, based on data gathered from more than 760 premenopausal and perimenopausal women, suggests that the frequency of sleep disruptions is associated with urinary concentrations of phthalates. It is the first known study to document this association. The relationship, however, appears complex, because other variables, such as smoking status, have been shown to influence the effect. More research is warranted to fully understand this association, as well as the underlying mechanisms of how hormones and EDC exposure influence sleep, particularly in midlife women.

Study results appear in the article “Associations of phthalate exposure and endogenous hormones with self-reported sleep disruptions: results from the Midlife Women’s Health Study.”

“This study raises concerns and additional questions about a possible contribution of phthalates to sleep disturbances in premenopausal and perimenopausal women. Additional research into these endocrine-disrupting chemicals and their interactions with hormones, sleep, and mood in midlife women is needed,” says Dr. Stephanie Faubion, NAMS medical director.

About this sleep research article

Source:
NAMS
Media Contacts:
Eileen Petridis – NAMS
Image Source:
The image is in the public domain.

Original Research: Closed access
“Associations of phthalate exposure and endogenous hormones with self-reported sleep disruptions: results from the Midlife Women’s Health Study”. by Hatcher, Katherine M.; Smith, Rebecca L.; Chiang, Catheryne; Li, Zhong; Flaws, Jodi A.; Mahoney, Megan M. Menopause.

Associations of phthalate exposure and endogenous hormones with self-reported sleep disruptions: results from the Midlife Women’s Health Study

Objective:
Follicle-stimulating hormone and estradiol (E2) have been associated with sleep in midlife women, however, few studies have examined the association of other hormones or environmental chemical exposure such as phthalates, with self-reported sleep quality. We assessed the relationship of self-reported sleep with hormones and phthalates.

Methods:
In total, 762 women (aged 45-54 y, 459 premenopausal, and 303 perimenopausal) from the Midlife Women’s Health Study answered self-reported questions regarding the frequency of sleep disturbances, insomnia, and restless sleep. Serum E2, progesterone, testosterone, serum hormone binding globulin, free E2 index, free testosterone index, E2:progesterone, and E2:testosterone were measured. Summary measures of phthalate mixtures, including the phthalates from plastic sources (sumPLASTIC), personal care products (sumPCP), di-(2-ethyhexyl) phthalate (sumDEHP), anti-androgenic phthalates (sumAA), and all phthalate metabolites measured (sumALL), were calculated from urinary phthalate metabolites. Ordinal logistic regression was used to fit each outcome sleep measure with all hormones and summary phthalates.

Results:
Progesterone and testosterone were significantly negatively associated with the frequency of sleep disturbances and insomnia. Free testosterone index was also negatively associated with insomnia frequency. E2:progesterone was positively associated with frequency of sleep disturbances and restless sleep in self-reported nonsmokers. SumPCP and sumALL were significantly negatively associated with frequency of sleep disturbances, insomnia, and restless sleep. SumDEHP and sumPLASTIC were negatively associated with insomnia frequency. Further, the direction of association between phthalates and sleep appears to be dependent on the quartile of phthalate exposure. All significant associations between phthalates and sleep were in self-reported nonsmokers or former smokers.

Conclusions:
Our study supports previous literature that hormones beyond follicle-stimulating hormone and E2 are associated with sleep disruptions in menopause. Further, we are among the first to show that phthalate exposure is associated with sleep disruptions in midlife women.