Shorter sleep duration linked to later onset of menopause

Key Takeaways:

• Hazard ratio for menopause was 0.88 for Japanese women who reported sleeping 6 hours or less per night vs. longer.
• More study is needed to determine the mechanism driving the association.

Japanese women who habitually slept 6 hours or less per night were more likely to experience menopause at an older age than those who reported longer sleep duration, according to data published in Menopause.

“We previously observed that shorter sleep duration on weekends was associated with higher total and free testosterone levels among premenopausal Japanese women with regular menstrual cycle,” Chisato Nagata, MD, PhD, of the department of epidemiology and preventive medicine at Gifu University Graduate School of Medicine, Japan, and colleagues wrote. “Therefore, there is a possibility that shorter sleep duration may be associated with later age at menopause.”

This prospective study included 3,090 premenopausal Japanese women aged 35 to 56 years from the Takayama study. Researchers determined habitual sleep duration by self-administered questionnaires taken at baseline. Menopause status was defined as the absence of menstruation for at least 12 months.

During 10 follow-up years, 1,776 of the women experienced natural menopause. Having a sleep duration of 6 hours or less was significantly associated with decreased risk for menopause (HR = 0.88; 95% CI, 0.78-0.99) with an HR of 1.03 for menopause with each addition hour of sleep (95% CI, 0.98-1.09). In total, 869 women reported getting 6 hours or less of sleep per night, 1,482 reported 7 hours, 635 reported 8 hours and 104 reported getting 9 hours or more of sleep per night. Of the women who reported shorter sleep of 6 hours or less, 69 reported sleeping 5 hours or less per night.

According to the researchers, there should be concern that sleep duration at baseline may no longer be relevant up to 10 years into follow-up, as an analysis conducted at only 5 years of follow-up demonstrated a slightly attenuated association that did not remain significant for 6 hours or less compared with 7 hours of sleep (HR = 0.91; 95% CI, 0.77-1.07).

The researchers noted that sleep might affect neuroendocrine hormone levels, such as melatonin, growth hormone, prolactin, cortisol, glucose and insulin, which may affect menopause onset.

“More evidence is needed for confirmation of our results,” the researchers wrote. “Future studies utilizing biomarkers would provide greater insight into the mechanisms linking duration of sleep and the onset of menopause.”