Insomnia and menopause have often been viewed as symptoms of growing older. But a pair of new studies is turning that idea on its head, suggesting both actually trigger aging.

The findings of the first study, published in the Proceedings of the National Academy of Sciences, indicate menopause speeds up cellular aging, increasing a woman's risk of age-related diseases. The researchers also found that the younger a woman is when she enters menopause, the faster she ages, Medical News Today reports.

A second study, published in Biological Psychiatry, found that symptoms of insomnia — which often occur alongside menopause — may also accelerate aging in postmenopausal women.

Steve Horvath, of the David Geffen School of Medicine at the University of California-Los Angeles (UCLA) and senior author of both studies, noted that researchers have long debated whether growing older causes menopause or vice versa.

"It's like the chicken or the egg: which came first?" he said. "Our study is the first to demonstrate that menopause makes you age faster."

Fo the first, Horvath and colleagues monitored methylation — a chemical biomarker of cellular aging — in the DNA samples of more than 3,100 women involved in four studies, one of which was the Women's Health Initiative. By analyzing methylation in blood, saliva, and buccal samples, the team was able to measure the biological age of the women's cells, and they compared this with their chronological age.

From their analysis, the researchers found that menopause accelerates cellular aging in the blood by around 6 percent. "That doesn't sound like much, but it adds up over a woman's lifespan," notes Horvath.

For the second study, Horvath and colleagues measured the cellular aging of 2,078 women who were part of the WHI. The researchers assessed the presence of insomnia symptoms among the women, which included restlessness, problems falling asleep, disrupted sleep, trouble getting back to sleep, and waking early.

The team found that women who had five symptoms of insomnia were almost 2 years older biologically, compared with women of the same chronological age who had no symptoms of the sleep disorder.
"The big question is which menopausal hormone therapy offers the strongest anti-aging effect while limiting health risks," said Horvath.