Knee Osteoarthritis Risk Factors: What Increases Your Chances

Key Takeaways

• Age is the single biggest risk factor—knee OA becomes much more common after 50
• Excess weight increases risk significantly, but losing even 10-15 pounds can help
• Previous knee injuries, especially to ligaments, raise your risk considerably
• Women are more likely to develop knee OA than men, particularly after menopause
• Many risk factors can be modified through lifestyle changes and preventive care

If you’re wondering whether you might develop knee osteoarthritis (OA), you’re asking the right question. Understanding your risk factors is the first step toward prevention—or at least slowing down the disease if you already have early signs.

The good news? While some risk factors are beyond your control, many others aren’t. Let’s break down what puts you at risk and what you can actually do about it.

The Risk Factors You Can’t Change

Let’s start with the honest truth: some things stack the deck against you, and there’s nothing you can do about them. But knowing these factors helps you understand why prevention matters even more.

Age: The Biggest Factor

Age is the single most important risk factor for knee osteoarthritis. Research shows that knee OA is rare before age 40, becomes increasingly common in your 50s and 60s, and affects more than half of people over 65.

Why? Your cartilage simply wears down over time. Years of walking, standing, climbing stairs, and moving put stress on the knee joint. While cartilage is remarkably durable, it eventually shows signs of wear—just like tires on a car.

What this means for you: If you’re in your 50s or older, prevention becomes critical. The steps you take now can make a significant difference in whether you develop symptoms later.

Gender: Women at Higher Risk

Women are about 40% more likely to develop knee OA than men. The risk increases dramatically after menopause, suggesting that hormonal changes play a role. Estrogen appears to have a protective effect on cartilage, so when levels drop, the risk rises.

Women also tend to have wider hips, which changes the angle at which the thighbone meets the knee joint. This can create uneven stress on the cartilage over time.

Genetics: Family History Matters

If your parents or siblings have knee OA, your risk is higher. Research suggests that genetics account for about 40-65% of knee OA risk. Scientists have identified specific genes that affect cartilage strength and how your body responds to joint stress.

However, having a family history doesn’t guarantee you’ll develop the condition. It just means you should pay extra attention to the risk factors you can control.

Previous Knee Injuries

A torn ACL, meniscus tear, or other significant knee injury can increase your risk of developing OA in that knee by three to six times. Even if the injury was surgically repaired, the trauma to the joint changes how cartilage wears over time.

Athletes who played high-impact sports (football, basketball, soccer) often develop knee OA earlier than the general population—sometimes in their 40s rather than their 60s.

The Risk Factors You CAN Change

Here’s where it gets empowering. These factors are within your control, and small changes can make a meaningful difference.

Excess Weight: The Most Modifiable Risk

Carrying extra weight is one of the strongest risk factors for knee OA—and one of the most controllable. Here’s why it matters so much:

Every pound you carry puts about 4 pounds of pressure on your knees when you walk. If you’re 20 pounds overweight, that’s an extra 80 pounds of force on your knee joints with every step.

Studies show that losing just 10-15 pounds can reduce knee pain by up to 50% in people who already have OA. For prevention, maintaining a healthy weight throughout your life is one of the best things you can do for your knees.

The evidence: A landmark study published in Arthritis & Rheumatism found that women who lost 11 pounds or more over 10 years reduced their risk of developing knee OA by more than 50%.

Occupation and Repetitive Stress

Jobs that require frequent kneeling, squatting, or heavy lifting can wear down knee cartilage faster. Occupations with elevated risk include:

• Construction workers
• Farmers
• Warehouse workers
• Healthcare workers (nurses, CNAs)
• Carpet installers
• Professional cleaners

If your job involves these activities, using knee pads, taking breaks, and practicing proper lifting techniques can help protect your joints.

Physical Activity Level: Finding the Balance

This one is tricky because both extremes are problematic.

Too little activity weakens the muscles around your knee, reducing support for the joint. It also contributes to weight gain, which we’ve already discussed.

Too much high-impact activity—especially sports that involve sudden stops, pivoting, and jumping—can accelerate cartilage wear. Marathon runners and professional athletes tend to develop knee OA earlier than moderately active people.

The sweet spot: Regular, moderate exercise that strengthens your leg muscles without putting excessive stress on your knees. Walking, swimming, cycling, and strength training are ideal.

Muscle Weakness: Often Overlooked

Weak quadriceps (thigh muscles) and hamstrings mean your knee joint has less support and stability. This allows more stress on the cartilage with every movement.

Research shows that people with stronger leg muscles are significantly less likely to develop knee OA—and if they do, they tend to have less severe symptoms.

The fix: Strength training exercises targeting your legs, done 2-3 times per week, can reduce your risk and slow progression if you already have early OA.

Joint Alignment Issues

Bowlegs (varus alignment) or knock-knees (valgus alignment) create uneven wear on knee cartilage. The misalignment causes more pressure on one side of the knee than the other.

While you can’t change your basic bone structure, orthotics, specific exercises, and in some cases bracing can help distribute weight more evenly across the joint.

How Much Does Each Factor Matter?

Not all risk factors are equal. Here’s what the research shows:

Risk Factor	Increased Risk
Age 50+	3-5x higher
Obesity (BMI 30+)	4-5x higher
Previous knee injury	3-6x higher
Female gender (post-menopause)	1.4x higher
Family history	2-3x higher
Repetitive knee stress (occupation)	2-3x higher

These factors also combine. A 55-year-old woman with a previous ACL injury and excess weight has a much higher risk than someone with just one of these factors.

What You Can Do Starting Today

Understanding your risk factors is only useful if you act on that knowledge. Here’s your action plan:

1. Maintain a Healthy Weight

If you’re overweight, losing even modest amounts can make a significant difference. Talk to your doctor about a safe, sustainable weight loss plan.

2. Strengthen Your Leg Muscles

Focus on exercises that build quadriceps, hamstrings, and hip muscles. Stronger muscles mean better knee support.

3. Choose Lower-Impact Activities

Swimming, cycling, elliptical training, and walking are easier on your knees than running, jumping, or sports with sudden direction changes.

4. Address Old Injuries Properly

If you’ve had a knee injury, work with a physical therapist to ensure proper rehabilitation. Don’t rush back to full activity before you’re ready.

5. Practice Good Workplace Ergonomics

If your job involves kneeling or heavy lifting, use proper equipment and techniques. Take breaks to change positions regularly.

6. Get Regular Check-Ups

If you have multiple risk factors, talk to your doctor about early screening. Catching knee OA in its earliest stages gives you more options for slowing progression.

The Bottom Line on Prevention

You can’t eliminate your risk of knee osteoarthritis entirely—especially if you have non-modifiable factors like age, gender, or genetics working against you. But you have more control than you might think.

The lifestyle choices you make today directly affect your knee health tomorrow. Maintaining a healthy weight, staying active in knee-friendly ways, and strengthening your leg muscles can significantly reduce your risk or delay the onset of symptoms by years.

Remember: prevention is always easier than treatment. If you’re already experiencing occasional knee pain or stiffness, don’t ignore it. Early intervention—whether through physical therapy, weight management, or other conservative treatments—can make a substantial difference in your quality of life.

Frequently Asked Questions

Can you prevent knee osteoarthritis if it runs in your family?

You can’t eliminate genetic risk, but you can significantly reduce it through lifestyle modifications. Studies show that people with family histories who maintain healthy weights and stay active have much better outcomes than those who don’t take preventive steps.

Is running bad for your knees?

Recreational running at moderate distances (20-30 miles per week) doesn’t increase OA risk for most people. However, marathon running and ultra-distance running may accelerate cartilage wear. The key is finding a balance that works for your body.

At what age should I start worrying about knee OA?

Prevention should start in your 30s and 40s, especially if you have risk factors. By your 50s, being proactive becomes critical since this is when OA typically begins to develop.

Can you reverse early knee osteoarthritis?

You can’t regenerate cartilage that’s already lost, but you can slow progression significantly through weight management, exercise, and sometimes treatments like hyaluronic acid injections. Early intervention makes a big difference.

Should I avoid exercise if I’m at high risk?

Absolutely not. Avoiding exercise actually increases your risk by weakening muscles and contributing to weight gain. The key is choosing the right types of exercise—lower-impact activities that strengthen without excessive stress.

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Last medically reviewed: February 2025

This article is for informational purposes only and does not constitute medical advice. Consult with a healthcare provider about your individual risk factors and prevention strategies.