Does aging cause menopause, or does menopause cause aging? It’s a long-running debate. But investigators at the University of California Los Angeles have published what they claim is the first study to demonstrate that menopause makes women age faster. Their research suggests that, in the future, science may be able to predict which women are at greatest risk for age-related diseases.
The researchers developed an accurate biomarker of aging called the “epigenetic clock.” This marker is based on age-related chemical changes in DNA called methylation.
Their work was published in two studies. In the first, known as the “menopause study,” the researchers took DNA samples from blood, saliva, and the cells from the inside of the cheek (buccal epithelium) of 3,100 women enrolled in four large studies, including the Women’s Health Initiative (WHI). They measured the biological age of these cells, to look at the correlation between each woman’s chronological age and the age of the cells in her body.
Menopause speeds up cellular aging by about six percent. “That doesn’t sound like much, but it adds up over a woman’s lifespan,”
The researchers also found that the cells they examined of women who took hormone replacement therapy (HRT) had a lower epigenetic age, Morgan Levine, a postdoctoral fellow at UCLA and the lead author of the menopause study, told TheDoctor.
In the second study, known as the “insomnia study,” the researchers looked at data from 2,078 women enrolled in the WHI. They used the same epigenetic biological clock as the menopause study to determine the women's biological age.
They found that women who reported five symptoms of insomnia (restlessness, difficulty falling asleep, waking at night, trouble getting back to sleep, and early awakening) were almost two years older biologically than those of the same chronological age without insomnia symptoms.
“We can’t conclude definitively from our study that insomnia leads to advanced epigenetic age,” said Judith Carroll, first author on the sleep study, “but these are powerful findings.”
Horvath, a professor of human genetics and biostatistics at UCLA, said that in the future scientists may use the epigenetic clock to evaluate the effect of therapies, such as HRT, for menopause.
Women who reported five symptoms of insomnia (restlessness, difficulty falling asleep, waking at night, trouble getting back to sleep, and early awakening) were almost two years older biologically than those of the same chronological age without insomnia symptoms.
“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.