As if the hot flashes, night sweats and dry skin caused by menopause weren’t indignity enough, a new UCLA study has found that the change of life also accelerates the body’s biological clock, increasing women’s risk for aging-related diseases and earlier death.
Published July 25 in the Proceedings of the National Academy of Sciences, the results could rekindle a national debate about the merits of hormone therapy, particularly for women who enter menopause early following surgical removal of the ovaries.
“For decades, scientists have disagreed over whether menopause causes aging or aging causes menopause,” said principal investigator Steve Horvath, a professor of human genetics and biostatistics at the David Geffen School of Medicine at UCLA and UCLA Fielding School of Public Health. “It’s like the chicken or the egg: which came first? Our study is the first to demonstrate that menopause makes you age faster.”
Using an epigenetic clock Horvath invented in 2013, he and first author Morgan Levine tracked methylation, a chemical biomarker linked to aging, to analyze DNA samples from more than 3,100 women enrolled in four large studies. In 2010, data from one of these studies was used to confirm the controversial finding linking hormone therapy to a higher risk of cardiovascular disease in menopausal women.
In the UCLA study, researchers measured the biological age of cells from blood, saliva and inside the cheek to explore the relationship between each woman’s chronological age and her body’s biological age.
“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.”
Take, for example, a woman who enters early menopause at age 42. Eight years later, her body would be a full year older biologically than another 50-year-old woman who entered menopause naturally at age 50.
On average, a woman who had both ovaries removed at 35 is one and a half biological years older than a pre-menopausal woman of the same age.
“The younger a woman is when she enters menopause, the faster her blood ages,” said Levine, a postdoctoral fellow in Horvath’s lab. “That’s 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.”
The UCLA finding echoed earlier studies showing that women who live past 100 tend to enter menopause later in life.
“Young women possess a strong health advantage over men the same age,” said Levine. “That benefit disappears at menopause, when declining sex hormones stop protecting women from cardiovascular diseases and many age-related illnesses.”
“Our results suggest that female sex hormones like estrogen and progesterone may influence aging and longevity,” said Horvath.
The coauthors propose that scientists in the future may use the epigenetic clock as a diagnostic tool to evaluate the effects of therapies, like hormone therapy for menopause. Researchers will try to answer the question of which menopausal hormone therapy offers the strongest anti-aging effect while limiting health risks, said Horvath.
“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,” said Horvath. “This could greatly reduce the length and costs of clinical trials and speed benefits to women.
The UCLA scientists next plan to study the effects of menopause and hormone therapy in fat, skin, vaginal and breast tissue, and to carry out long-term studies of biological aging in the same women before and after menopause.