If your shoulder has been aching, catching, or waking you up at night, you're not alone. Shoulder pain affects nearly half of us in any given year, and up to 70% of people will deal with it at some point in their lives. One of the most common causes is something called rotator cuff tendinopathy — a term that sounds technical but is worth understanding, because the research tells us a lot about who gets it and why.
A major review published in the Journal of Rehabilitation Medicine looked at 16 separate studies on this exact problem. Here's what they found, in plain English — and what it means for you.
What Is Rotator Cuff Tendinopathy?
The rotator cuff is a group of four small muscles and tendons that wrap around your shoulder joint and keep it stable. "Tendinopathy" is the umbrella term used when one or more of these tendons is irritated, overloaded, or starting to break down. It also covers conditions you might have heard of before — subacromial bursitis, shoulder impingement, and rotator cuff tendinitis.
The hallmark signs are pain and weakness when you lift your arm out to the side or rotate it. Reaching up to a high shelf, putting on a seatbelt, sleeping on that side — these become the moments you really notice it.
It's also stubborn. Around 40% of people don't respond well to standard conservative treatment, and more than half report the pain coming back over the long term. That's exactly why understanding the risk factors matters — prevention and early intervention are far more effective than trying to fix it once it's entrenched.
The Three Biggest Risk Factors
The researchers identified 22 different factors linked to rotator cuff tendinopathy. Three stood out with the strongest evidence:
1. Age over 50 — People over 50 had more than 3 times the risk of developing rotator cuff tendinopathy compared with younger people. As tendons age, they lose elasticity and tensile strength. The collagen fibres degenerate, and the tendon simply doesn't tolerate load the way it used to.
2. Diabetes — People with diabetes had more than double the risk. This one surprises many patients. High blood sugar affects how collagen — the building block of tendons — cross-links and behaves. It reduces the strength and quality of the tendon tissue. People with diabetes also tend to have reduced shoulder mobility and muscle strength, even before any pain shows up.
3. Working with your arms above shoulder height — People who regularly work with the shoulder above 90 degrees (think electricians, painters, builders, hairdressers, warehouse pickers) had around 2.4 times the risk. Lifting your arms overhead increases pressure inside the rotator cuff muscles and compresses the tendons against the bone above them. Do that for hours a day, years on end, and the tendons start to suffer.
What Else Came Up
Other factors with smaller but still meaningful effects included heavy manual work, repetitive tasks, high-force jobs, vibration exposure (think jackhammers and chainsaws), swimming, weight training, high psychological work stress, and even job dissatisfaction. Cardiovascular disease and a larger waist circumference were also linked.
The picture that emerges is clear: rotator cuff tendinopathy isn't usually caused by one thing. It's a build-up — your age, your health, your job, and how you load your shoulder all stack on top of each other.
What This Means For You
Some of these risk factors you can't change. You can't reverse your age. But many of them you absolutely can influence:
If you have diabetes, tight blood sugar control protects your tendons, not just your heart and kidneys.
If your job involves overhead work, building stronger shoulder and shoulder-blade muscles changes how your tendons handle load.
If you're over 50 and active, smart loading — gradual increases, proper technique, recovery time — matters more than ever.
If your shoulder is already grumpy, don't wait it out. Tendons that get caught early respond far better than tendons left to deteriorate.
The takeaway from this research isn't that shoulder pain is inevitable as you age. It's that the risk factors are now well understood, which means so are the levers you can pull to protect yourself.
If your shoulder has been giving you trouble, the difference between a 6-week fix and a 6-month problem is often how quickly you get it properly assessed. That's exactly what we're here for.
Reference
Leong, H. T., Fu, S. C., He, X., Oh, J. H., Yamamoto, N., & Yung, S. H. P. (2019). Risk factors for rotator cuff tendinopathy: A systematic review and meta-analysis. Journal of Rehabilitation Medicine, 51(9), 627–637. https://doi.org/10.2340/16501977-2598
Written by the team at Leaton Performance & Rehabilitation, Eden Terrace, Auckland.