Fifteen percent of those over the age of 30 suffer from osteoarthritis—a degenerative condition and the most common form of arthritis, affecting millions worldwide.

That’s according to a study published Monday in journal The Lancet Rheumatology, led by scientists at the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, and partially funded by the Bill & Melinda Gates Foundation.

Researchers examined osteoarthritis prevalence in 204 countries and territories from 1990 through 2020. Based on this data, they were able to forecast how many people are expected to develop the condition worldwide by 2050—a whopping 1 billion.

Among other findings: Nearly 600 million people had osteoarthritis in 2020, amounting to almost 8% of the global population—and an increase of 132% since 1990.

With people living longer and the world population growing, the rising disease burden is bound to place additional stress on the health care systems of most countries, Jaimie Steinmetz, a lead researcher at IHME and one of the paper’s authors, said in a news release on the study.

“There is no effective cure for osteoarthritis right now, so it’s critical that we focus on strategies of prevention, early intervention, and making expensive, effective treatments like joint replacements more affordable in low- and middle-income countries,” she said.

Risk factors for developing osteoarthritis

It may surprise you, but even those in their twenties and thirties can develop arthritis—though there’s usually a specific reason for someone developing the condition so young, like joint injury or repetitive joint stress.

By the time you reach your thirties and forties, “there’s often enough cumulative wear and tear on the joints that you might start feeling aches and pains,” Dr. Steven DeFroda, orthopedic surgeon and sports medicine specialist at MU Health Care, said in a recent University of Missouri blog entry.

The chance of developing the condition increases with time. While “there’s no set age that you’ll just wake up with joint pain,” DeFroda said, “you might find you’re noticing your joints more than you did when you were a kid” during these two decades.

Age isn’t the only factor that increases arthritis risk. So does weight. Those in their thirties and forties often exercise less and, thus, put on more weight, placing additional stress on joints, according to DeFroda. This usually happens first below the waist, because the legs carry most of the body’s weight and endure frequent repetitive motion while walking.

“Cartilage can start to fray, become swollen, or not stay as smooth as it was when we were children,” he said. “The natural aging process and cumulative stress on your joints start causing pain.”

Age- and weight-related damage can eventually lead to osteoarthritis. In 2020, obesity was the reason behind 20% of disabling cases of the condition, according to the study. And for those age 70 and older, osteoarthritis was the seventh most common cause of disability.

Other risk factors include:

• Inflammatory or autoimmune conditions

• Prior joint injury: This is a leading cause of osteoarthritis in younger adults.

• Repetitive activities or overuse

• Gender: Women are more likely than men to develop the condition after age 50, according to the University of Missouri. And in 2020, the majority of cases of osteoarthritis—61%—were in women, according to the study.

Researchers are investigating why women develop the condition more often than men. “Researchers believe that genetics, hormonal factors, and anatomical differences play a role,” Dr. Jacek Kopec, senior author of the paper and professor in the School of Population and Public Health at the University of British Columbia, said in the news release.

Symptoms of osteoarthritis

Symptoms of the potentially debilitating condition usually develop slowly over time. They can include, according to the Arthritis Foundation…

• Pain or aching in a joint during or after activity, or at the end of the day

• Joint stiffness, usually early in the morning or after resting

• Limited range of motion that may get better with movement

• Clicking or popping when you bend your joint

• Joint swelling

• Muscle weakness around your joints

• Joint instability or buckling, as when your knees give out

And it can affect different areas of the body, including…

• Hips

• Knees

• Fingers

• Feet

Living your best life with osteoarthritis

If you’re noticing symptoms, you’ll want to mention them to your primary care provider, who will look at how you move and may order an X-ray or MRI—and/or a procedure called a joint aspiration, which involves pulling fluid out of a joint with a needle after numbing the area.

Treatment options may include pain relievers, over-the-counter products called counterirritants, anti-inflammatory steroids, plasma injections, or other drugs, according to the Arthritis Foundation. Surgery is also a possibility for some patients.

The good news: There are other, more holistic ways of tackling the issue, including exercise (150 minutes of moderate to vigorous exercise per week is the goal). An osteoarthritis-targeted exercise plan to reduce pain and stiffness will include these four components, according to the foundation:

• Strengthening exercises, to ease stress around painful joints

• Range of motion exercises or stretching, to reduce stiffness and keep joints limber

• Aerobic or cardio exercises, to improve stamina and energy, and to help shed excess weight

• Balance exercises, to strengthen small muscles around the knees and ankles, in an effort to prevent falls

“It’s counterintuitive, but having joint pain doesn’t mean we should remain sedentary,” Dr. Liane Ong, a lead research scientist at IHME who supervised and coauthored the study, said in the news release. “Being physically active can prevent injuries earlier in life and can even be beneficial for someone with joint pain.”

Physical therapy; assistive devices like braces or shoe inserts; and weight-loss programs can also improve symptoms.