For years, scientists have disagreed on whether menopause causes aging or aging leads to menopause, giving rise to a “which came first” debate. New epigenetic research may help settle this long-standing disagreement, offering evidence that menopause might actually make a woman age faster. Two recent UCLA studies show that menopause and its common side effect – insomnia – may accelerate aging. This could potentially increase a woman’s risk for diseases related to aging and possibly lead to an earlier death. The group of researchers from UCLA published their dual findings in Proceedings of the National Academy of Sciences and Biological Psychiatry.
Chronological age and biological age are two different concepts, one which is determined simply by how long you’ve been alive and the other by how old you are on a cellular level, or in this case, an epigenetic level. Steve Horvath, senior author and professor of human genetics and biostatistics at the David Geffen School of Medicine at UCLA and UCLA Fielding School of Public Health, recently developed a method for determining one’s “epigenetic clock” by measuring DNA methylation levels and tracing the epigenetic changes in various sample types. DNA methylation is an epigenetic modification that occurs as one ages, defined by the addition of a methyl group to DNA.
In the menopause study, the group of researchers tracked DNA methylation in samples of over 3,100 women, including those in the 15 year program called Women’s Health Initiative (WHI). Their results suggest that the hormonal changes that accompany menopause accelerate biological aging in women and not the other way around. “We discovered that menopause speeds up cellular aging by an average of 6 percent,” said Horvath. “That doesn’t sound like much, but it adds up over a woman’s lifespan.”
For instance, let’s say a woman enters early menopause when she’s 42. When she’s 50, her biological age will be an entire year older than another 50 year old woman who naturally begins menopause at 50 years of age.
Morgan Levine, first author and postdoctoral researcher in Horvath’s Lab, explained, “On average, the younger a woman is when she enters menopause, the faster her blood ages. This is significant because a person’s blood may mirror what’s happening in other parts of the body, which could have implications for death and disease risk.”
In the sleep study, researchers found that postmenopausal women who reported having five insomnia-related symptoms tended to be older biologically. Using the same “epigenetic clock” method as Horvath, they assessed over 2,000 women in the WHI and found that those who wake up repeatedly throughout the night, have restless sleep, difficulty falling asleep, trouble getting back to sleep, and wake up too early in the morning are likely to be biologically older than women who are of a similar chronological age.
Judith Carroll, first author of the sleep study and assistant professor of psychiatry at the UCLA Semel Institute for Neuroscience and Human Behavior and the Cousins Center for Psychoneuroimmunology, said, “Not getting restorative sleep may do more than just affect our functioning the next day; it might also influence the rate at which our biological clock ticks.” Previous research has shown that even one night of poor sleep could epigenetically impact genes related to our circadian clock.
The authors caution that they cannot definitively conclude that insomnia results in an older epigenetic age, however, their findings are important, Carroll said. She points to the need for additional studies focusing on the same women over time to truly identify a causal relationship between sleep disorders and biological age.
Although these results may be somewhat disheartening for women, there is hope. More studies could lead to improvements in anti-aging menopausal hormone therapy and a better diagnosis of therapy efficacy.
“No longer will researchers need to follow patients for years to track their health and occurrence of diseases. Instead, we can use the epigenetic clock to monitor their cells’ aging rate and to evaluate which therapies slow the biological aging process,” explained Horvath. “This could greatly reduce the length and costs of clinical trials and speed benefits to women.”
Sources: Levine, M. et al. (2016). Menopause accelerates biological aging. PNAS, 113(33):9327-9332.
Carroll, J., et al. (2016). Epigenetic aging and immune senescence in women with insomnia symptoms: Findings from the Women’s Health Initiative StudyEpigenetic Age and Insomnia. Biological Psychiatry.
Reference: UCLA Health System. Hot News Flash! Menopause, sleepless nights make women’s bodies age faster. Newswise. 22 Jul 2016. Web.
