Arthritis can start at any age, but most people are diagnosed after 45. CDC data from 2022 shows arthritis prevalence climbs steeply with age, from 3.6% of adults between 18 and 34 to 53.9% of those 75 and older. The specific age depends heavily on which type of arthritis you’re talking about, because “arthritis” is actually an umbrella term covering more than 100 conditions with very different timelines.
Osteoarthritis: The Most Common Type
Osteoarthritis is the form most people picture when they think of arthritis. It results from cartilage wearing down over years of use, and it accounts for the majority of arthritis cases. About 88% of people with osteoarthritis are 45 or older, and 43% are 65 or older. The annual rate of new knee osteoarthritis diagnoses peaks between ages 55 and 64.
That said, more than half of people with symptomatic knee osteoarthritis are actually younger than 65. This isn’t a disease that waits for old age. Joint injuries from sports, falls, or accidents can trigger osteoarthritis in the affected joint years or even decades later, which is why some people in their 20s and 30s develop it. UCSF Health notes that while osteoarthritis is most common in people over 50, it can develop after any injury that damages a joint.
There’s also a notable sex difference. Before age 45, osteoarthritis is more common in men. After 45, it becomes more common in women, likely due to hormonal shifts around menopause that affect joint tissue.
Rheumatoid Arthritis: Often Starts in Midlife
Rheumatoid arthritis (RA) is an autoimmune condition where the immune system attacks the lining of the joints, causing pain, swelling, and eventually joint damage. It’s a fundamentally different process from osteoarthritis. RA can technically start at any age, but incidence rises significantly after 40, with peak onset between 60 and 70 years old.
Women develop RA two to three times more often than men. The disease tends to affect smaller joints first, particularly the hands and feet, and it often appears symmetrically on both sides of the body. Early treatment makes a significant difference in outcomes, so recognizing it matters. If you’re experiencing joint stiffness that lasts more than 30 minutes each morning along with swelling in multiple joints, that pattern points more toward RA than simple wear-and-tear arthritis.
Psoriatic Arthritis: Ages 30 to 55
Psoriatic arthritis typically develops between ages 30 and 55, according to Mayo Clinic. Most people who develop it already have psoriasis, sometimes for years before any joint symptoms appear. It can affect any joint and often causes fingers or toes to swell into a sausage-like shape. If you have psoriasis and start noticing joint pain or stiffness, that history is an important clue to the type of arthritis involved.
Gout: Typically After 40 in Men
Gout causes sudden, intense flares of joint pain, most famously in the big toe. It happens when uric acid crystals build up in a joint. Men tend to experience their first gout attack after age 40. Women are largely protected until menopause, when declining estrogen levels reduce the body’s ability to clear uric acid. This means women’s first gout episodes typically come a decade or two later than men’s.
Ankylosing Spondylitis: A Young Person’s Arthritis
Ankylosing spondylitis breaks the pattern of arthritis being an older person’s disease. It almost always starts before age 45, with early symptoms typically appearing between 15 and 30. It primarily affects the spine and the joints where the spine meets the pelvis, causing deep, aching lower back pain and stiffness that’s worse in the morning and improves with movement. Because back pain is so common in young adults, ankylosing spondylitis often gets dismissed for years before a diagnosis is made.
Juvenile Arthritis: Under Age 16
Children get arthritis too. Juvenile idiopathic arthritis (JIA) is diagnosed in children under 16 who have unexplained joint pain, stiffness, or swelling lasting at least six weeks. It’s an autoimmune condition, not a wear-and-tear problem, and it affects roughly 300,000 children in the United States. Some children outgrow it, while others carry it into adulthood.
Why Some People Get Arthritis Earlier
Several factors push the timeline earlier. A previous joint injury is one of the strongest predictors of early osteoarthritis. Athletes who tear a knee ligament, for instance, have a significantly elevated risk of developing arthritis in that knee within 10 to 15 years, regardless of how young they were at the time of injury. Obesity also accelerates the process by placing extra mechanical stress on weight-bearing joints and by promoting chronic low-level inflammation throughout the body.
Genetics play a role across all types of arthritis. Having a close family member with RA, for example, increases your own risk. Smoking is a well-established trigger for RA specifically, and it makes the disease more aggressive once it starts. For gout, diet and alcohol consumption influence uric acid levels and can bring on attacks earlier in life.
The Diagnosis Gap
Many people live with arthritis symptoms for months or years before getting a formal diagnosis. A large Danish study tracking patients with RA, psoriatic arthritis, and ankylosing spondylitis found that in the year 2000, the average time from first symptoms to diagnosis ranged from 30 months for RA to over five years for ankylosing spondylitis. That gap has narrowed dramatically with improved awareness and diagnostic tools, dropping to three to four months by 2011, but delays still happen. Persistent joint pain that doesn’t resolve within a few weeks, morning stiffness that lasts longer than 30 minutes, or swelling with no clear cause are all signals worth investigating rather than waiting out.