When do women really need a bone scan?

In the last few years, there’s been a cultural push for women in midlife to build strong bones.

Menopause influencers and medical organizations alike have focused on the message that women’s risk for fractures increases dramatically after menopause, and that they should think about their bone density much earlier than their mothers might have.

The American Medical Association recommends that women get their first DEXA scan — a low-dose X-ray that is the gold standard test for determining bone density — at 65 or older, unless they have a risk factor for osteoporosis.

But a growing number of doctors and bone health experts now recommend earlier scans. They argue that if women wait until 65, they may miss a critical window to prevent osteoporosis.

“For years, osteoporosis has been thought of as something that we identify and treat, not something we prevent,” said Dr. Jocelyn Wittstein, an associate professor of orthopedic surgery at Duke University School of Medicine. As researchers have learned more about prevention, that mindset has begun to shift, she said.

And yet the scans have not been studied as a screening tool for younger women without known risk factors for fractures, and no major medical organization supports this approach.

Here’s what to know about when to get a DEXA scan and how to take care of your bone health.

How Your Bones Change Over Time

Your bones are constantly rebuilding themselves, said Dr. Angela Cheung, the director of osteoporosis care for the University Health Network in Toronto.

Women reach their peak bone mass by their 20s to 30s. Generally, the more weight-bearing exercise you have done throughout your life — or activity that requires your body to resist gravity, such as jumping or resistance training — the stronger your bones will be, as long as you have maintained good nutrition.

Women see a significant drop in bone density in the years around menopause, which typically happens between 45 and 55. This is because estrogen, which plummets during menopause, helps bones stay strong.

Without taking steps to preserve their bone density, women lose an average of 10% of it in the five to seven years after menopause.

For women who start out with high bone density, this drop in estrogen may not lead to weak bones, Cheung said. But for many other women, the transition can lead to osteoporosis.

Many risk factors also predispose women to the disease, including a history of eating disorders, smoking, heavy drinking, a family history of osteoporosis or simply being thin.

What a DEXA Scan Can Tell You

You’re never too young to think about your bones, experts say: The sooner you prioritize weight-bearing exercise and good nutrition, the better off you will be.

But osteoporosis is often referred to as a silent disease, because many women only learn they have it after a fracture, the experts said.

A DEXA scan measures the density of your hip and spine bones. It can tell you whether you have osteopenia, a condition that can be a precursor to osteoporosis. It can also identify osteoporosis and help you determine whether to start medication to reduce your risk of fractures. After the scan, your provider will share a score that indicates whether your density is normal or low.

DEXA scans for body composition, offered by some gyms and wellness centers, can provide insights into muscle and fat tissue but they are not especially revealing about fracture risk, Cheung said.

The current medical recommendations for DEXA scans focus on screening older women for osteoporosis to prevent fractures, because research on the disease has focused on this population, said Dr. Joel Tsevat, a member of the U.S. Preventive Services Task Force, an expert panel that decides which screenings insurance companies must cover.

(To date, no major studies have been published on the preventive health benefits of performing DEXA scans on women who are under 65 and at average risk for fractures.)

Still, Tsevat said that women younger than 65 who have gone through menopause and have at least one additional risk factor should discuss earlier screening with their provider.

The Argument for Earlier DEXA Scans

Most women’s health advocates who push for earlier DEXA scans agree that the ideal time for women to learn their bone density is at menopause, when they face the choice of whether to start hormone therapy.

Research has shown that estrogen therapy can help to preserve a woman’s bone density, so knowing your score can be a valuable tool in deciding whether to take the hormone, said Mary Bouxsein, a bone health researcher and professor at Harvard Medical School. (The efficacy can vary based on dose and formula.)

But the therapy is most effective and safest if you start it within 10 years of menopause — which, for most women, means before 65, Bouxsein said.

On social media, a small but vocal contingent of doctors and physician influencers has argued that all women should receive a baseline DEXA scan in their 30s or early 40s. (Last year, an orthopedic surgeon in Kansas City started a campaign for women to get an initial scan at 40, the same age women are advised to get their first mammogram.) Some of these proponents offer DEXA scans at private clinics and sell products marketed to support bone density.

They argue that by getting an initial DEXA before menopause, you can learn your starting point, which could be useful when estrogen starts to drop. If you get a second DEXA at menopause and learn that your bone density has rapidly decreased, this could influence your decision to start hormone therapy.

But while most experts agree that getting a DEXA scan before menopause isn’t harmful, some argue it could create a false sense of security or anxiety, depending on a woman’s results.

And for most women, knowing their score that early on doesn’t change what they can do to prevent disease. (Though some premenopausal women at high risk for fractures, including some athletes and cancer patients, can benefit from earlier DEXA scans, the experts said.)

How to Protect Your Bones

Whether your DEXA score is normal or low, similar steps can help lower your risk of falls and fractures.

Regular resistance training and exercise that involves impact can help keep your bones strong, said Lora Giangregorio, a professor of kinesiology at the University of Waterloo in Canada.

While some fitness influencers claim you have to lift heavy weights to strengthen bone, it’s more important to start at a level that’s challenging for you and progressively push yourself over time by increasing the weight you’re lifting or choosing a harder exercise, Giangregorio said.

Beyond strengthening your bones, working on your balance, mobility and stability can help to prevent falls, she said.

It’s also important to eat enough calories to fuel your workouts and daily activities, to eat a diet rich in calcium and vitamin D, and to avoid smoking and excessive alcohol use.

Ultimately, many of the same habits that support your overall health and well-being throughout your life benefit your bones, too, Wittstein said.

“Luckily, the same things are often good for your heart and your muscles and your bones,” she added. “There’s so much overlap.”

This article originally appeared in The New York Times.