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Common Causes of Osteoarthritis

7th June 2021

If you are questioning why you got knee osteoarthritis, this article will give you a deeper insight into the common causes and risk factors.

As the most common type of joint inflammation, osteoarthritis is affecting millions of people every year. According to a WHO report, 130 million people will be diagnosed with osteoarthritis by 2050, and one-third of them will be severely disabled.

So, what exactly is the reason behind osteoarthritis? Knowing the common causes can help you to take precautions and change your lifestyle to minimize the risk and the impact.

How Does Osteoarthritis Occur?

Osteoarthritis is a type of arthritis where the cartilage in your weight-bearing joints in the legs starts to break down and wear away. Under normal conditions, the cartilage in your joints serves as a shock absorber when compressed. The stiffness and breakdown of the cartilage mean increased friction in the joints, which causes inflammation. The joint inflammation manifests in the body as joint aches, swelling, and stiffness that worsen over time.

Causes / Risk Factors

Obesity

Obesity is one of the greatest risk factors for OA. It was estimated that people suffering from obesity were seven times more likely to develop knee OA than normal-weight people [1].

There are two factors behind the link between obesity and OA. The first one is obvious: The more weight you have, the more pressure your joints will have to bear, and the faster your cartilage will erode. More specifically, every kg of extra weight adds a 4 kg pressure on each knee joint.

There is more: The excess fat in your body facilitates the release of inflammation-causing proteins that can travel to your joints. If you are already dealing with OA, being obese can increase joint swelling because of these proteins [2].

Previous Injury

Sports-related knee joint injuries can drastically increase the risk of OA. In young people, knee injuries were associated with a six-fold higher risk of developing OA. Of various knee injuries, the ones with the greatest risk factors are cruciate ligament injury, meniscal tear, and fracture of the tibia plateau/patella [3].

Original Source

A study from Finland created a model to explain a possible mechanism of cartilage degradation due to tissue deformation and fluid leakage through the injury surface [4]. Nevertheless, the exact relation between knee injuries and OA is not thoroughly understood.

Work-related Activities

If your job involves hard labour, it could accelerate the degradation of your cartilage. Work-related OA develops gradually through the accumulation of microtrauma caused by prolonged exposure to small pressures.

Original Source

The jobs that increase the OA risk usually involve lots of squatting, climbing, kneeling, and machinery that transmits vibrations to the joints. That’s why miners and construction workers are at a higher risk, almost four times higher than those working in an office job. Rugby players, dressmakers, and instrumentalists are also among high-risk groups.

Age

Throughout the last decade, half of the world’s population over 65 developed OA [5], making age one of the most prominent risk factors. That said, it is not aging itself that causes OA, but rather the changes in your skeleton and muscles that make you more susceptible to the disease.

More specifically, as you age, your tendons and ligaments become stiffer due to the changes in the structure of the collagen network in your bones. The decrease in bone elasticity impairs the joint functionality, making the cartilage more prone to wear and tear [6].

Gender

Your gender can play a huge role in the risk of developing OA, as backed by several studies. Women over 50 are 3.5 times more likely to develop hand OA and 40% more like to develop knee OA [7].

Experts mainly point out two reasons. One of them is the changes in hormone levels during menstruation and menopause could increase joint laxity by loosening your ligaments. The other reason is the anatomical differences between the two genders, such as different bone articulation and less cartilage in women.

Genetic

If your family has a history of OA, your chances of developing it can increase by anywhere between 30% and 70%. OA in the family does not necessarily mean you will develop the disease, but the inherited gene defects in the joint make you more vulnerable and increase the risk [8].

Conclusion

The exact cause of your OA will determine the best treatment for you. If your profile fits one or more of these factors, you should take that into account and talk to your practitioner regarding the most suitable treatment for your osteoarthritis.

[1] Coggon, D., et al. "Knee osteoarthritis and obesity." International journal of obesity 25.5 (2001): 622-627.

[2] King, Lauren K et al. “Obesity & osteoarthritis.” The Indian journal of medical research vol. 138,2 (2013): 185-93.

[3] Snoeker, Barbara, et al. "Risk of knee osteoarthritis after different types of knee injuries in young adults: a population-based cohort study." British journal of sports medicine 54.12 (2020): 725-730.

[4] Mononen, Mika E., et al. "New algorithm for simulation of proteoglycan loss and collagen degeneration in the knee joint: data from the osteoarthritis initiative." Journal of Orthopaedic Research® 36.6 (2018): 1673-1683.

[5] Hügle, Thomas, et al. "Aging and osteoarthritis: an inevitable encounter?." Journal of aging research 2012 (2012).

[6] Shane Anderson, A, and Richard F Loeser. “Why is osteoarthritis an age-related disease?.” Best practice & research. Clinical rheumatology vol. 24,1 (2010): 15-26. doi:10.1016/j.berh.2009.08.006

[7] Prieto-Alhambra, Daniel, et al. "Incidence and risk factors for clinically diagnosed knee, hip and hand osteoarthritis: influences of age, gender and osteoarthritis affecting other joints." Annals of the rheumatic diseases 73.9 (2014): 1659-1664.

[8] Spector, Tim D., and Alex J. MacGregor. "Risk factors for osteoarthritis: genetics." Osteoarthritis and cartilage 12 (2004): 39-44.

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