OVERVIEW

What is Kashin-Beck disease?

Kashin-Beck disease is an endemic, chronic, and deforming osteoarthropathy primarily characterized by degeneration and necrosis of articular cartilage in the limbs of developing children, followed by secondary osteoarthrosis.

What are the characteristics of Kashin-Beck disease endemic areas?

Regions where Kashin-Beck disease is prevalent generally have selenium deficiency in the natural environment. Selenium levels in drinking water, soil, and crops in these areas are lower than in non-endemic regions. More cases occur in damp and low-lying areas.

Which regions in China have high incidence of Kashin-Beck disease?

Kashin-Beck disease is widely distributed in China, occurring in provinces from the northeast to the southwest.

It mainly affects 13 provinces and regions: Hebei, Shanxi, Inner Mongolia, Liaoning, Jilin, Heilongjiang, Shandong, Henan, Sichuan, Tibet, Shaanxi, Gansu, and Qinghai. It is commonly found in cold, damp valley areas and rarely occurs in plains.

With the comprehensive prevention and control measures vigorously implemented in China, the 2019 surveillance data from the Chinese Center for Disease Control and Prevention showed that, except for Tibet Autonomous Region (elimination rate of 69.43%), the other 12 provinces achieved a 100% elimination rate, indicating that Kashin-Beck disease has been largely eradicated^[1].

SYMPTOMS

What are the main symptoms of Kashin-Beck disease?

Kashin-Beck disease primarily affects children and adolescents, with very few new cases in adults, and no significant gender difference. It typically occurs around ages 7–8, with earlier onset in severe endemic areas.

The disease progresses insidiously, and patients are often unaware of it in the early stages, usually discovering it only when the disease has advanced.

Early symptoms: Before joints become visibly enlarged or deformed, the disease features are often subtle, but its main clinical manifestations are related to osteochondral and joint damage. The following conditions warrant attention:

• Bilateral joint pain: Mainly occurs in the knees, ankles, and finger joints, presenting as dull or aching pain that worsens after physical labor.

• Distal finger joints bending noticeably toward the palm.

• Stiffness in limb joints, soreness when making a fist, inability to quickly extend fingers, and limited elbow extension.

Progressive and late stages: In addition to worsening joint pain, the following symptoms may appear:

• Gradual thickening of finger, knee, and ankle joints; increased restriction in elbow movement, preventing full extension (range of motion progressively decreases). Finger flexion becomes limited, fingertips fail to touch the palm when making a fist, and the clenched fist cannot be quickly straightened.

• Severe joint stiffness upon waking, improving slightly after movement. Patients often need to support themselves and walk briefly to adapt before walking normally.

  As the disease progresses, patients may develop knee varus (bow-leggedness) or valgus (knock-knees).

• Joint crepitus (grating sounds), possibly due to rough joint surfaces, hyperplasia, or shedding of synovial villi.

• Joint locking: During activities like walking or running, the knee suddenly becomes stuck, immobile, and accompanied by sharp pain.

  Mild cases may resolve by shaking the knee, while severe cases require medical intervention.

• Severe cases may develop skeletal muscle atrophy, primarily in the flexor muscles of the calves and forearms. Some patients experience atrophy before obvious joint changes.

• Finger joint deformities, such as shortened phalanges, reduced hand proportions, or disproportionate finger/toe lengths.

  Patients with early-onset and severe disease may exhibit short-limb deformities and stunted growth, earning Kashin-Beck disease the nickname "dwarfism disease."

CAUSES

What is Kashin-Beck disease caused by?

Current research findings are not yet unified, but it is generally believed that selenium deficiency is one of the important factors contributing to Kashin-Beck disease.

Numerous studies have shown that in areas where Kashin-Beck disease is prevalent, environmental selenium levels are significantly lower compared to other regions. Additionally, targeted selenium supplementation for children in high-risk areas can effectively improve joint and cartilage lesions and reduce the incidence of the disease.

However, some studies have found that certain low-selenium areas have not experienced outbreaks of Kashin-Beck disease, and in some low-selenium regions without selenium supplementation interventions, the prevalence has significantly declined in recent years.

Is Kashin-Beck disease related to eating moldy grains?

Yes.

Current research indicates that grains in Kashin-Beck disease-endemic areas are prone to contamination by Fusarium fungi during processes such as harvesting, handling, and storage before consumption.

Fusarium can produce toxins harmful to the body, leading to the development of Kashin-Beck disease. Among grains, wheat and corn are susceptible to Fusarium contamination, while rice is generally unaffected.

Therefore, in endemic areas, reducing the intake of wheat and corn and switching to rice as a staple food can help prevent Kashin-Beck disease.

Is Kashin-Beck disease related to drinking water pollution?

Possibly.

Studies have found that drinking water in Kashin-Beck disease-endemic areas contains high levels of organic pollutants, primarily derived from soil humus or natural decomposition of plant matter.

Animal experiments have shown that these organic pollutants cause significant damage to bone and cartilage in rats.

As a result, many researchers propose the hypothesis of organic water poisoning, suggesting that organic pollutants from plant decomposition or soil humus may contaminate drinking water, leading to chronic poisoning and the onset of Kashin-Beck disease.

Is Kashin-Beck disease related to genetics?

Yes.

Kashin-Beck disease exhibits familial clustering. Prolonged exposure to high-risk environments in endemic areas may influence genetic polymorphisms, potentially leading to the transmission of the disease across generations.

DIAGNOSIS

What tests are needed for Kashin-Beck disease?

X-ray examination (multiple symmetric X-ray changes in the distal phalanges are characteristic signs of Kashin-Beck disease), combined with age and affected areas for differential diagnosis.

Does osteoarthritis mean Kashin-Beck disease?

No, it could also be other diseases.

Degenerative joint disease: Mainly manifests as joint pain, stiffness, and swelling. However, it predominantly occurs in people over 40, and joint involvement is asymmetric.

Rheumatoid arthritis: Mainly manifests as morning stiffness (joint inflexibility upon waking) and polyarticular, symmetric joint inflammation. It mostly occurs between ages 40–60 and may lead to joint deformities.

Kashin-Beck disease primarily affects bones and joints, rarely involving other organs, whereas rheumatoid arthritis can affect other organs and cause systemic symptoms.

Gout: Often involves multiple joints, causing swelling and pain, but it is asymmetric and presents with acute inflammatory symptoms like redness, swelling, heat, and pain in the joints.

TREATMENT

How to treat Kashin-Beck disease?

The treatment outcome of Kashin-Beck disease depends on how early it is detected. Early detection, diagnosis, and treatment are crucial. If joint deformation has already occurred, the condition cannot be cured. Therefore, if related symptoms are noticed, it is advisable to seek medical attention promptly.

Doctors will provide appropriate treatment recommendations based on the condition.

• Patients with mild clinical symptoms (joint pain, swelling, but recoverable with rest):

  Reducing workload and increasing rest time are effective approaches for such patients.

  If the pain is severe and unbearable, painkillers may be taken as needed.

  Additionally, cartilage-nourishing medications such as glucosamine and chondroitin sulfate can promote cartilage matrix synthesis and alleviate joint cartilage damage.

• Patients with moderate clinical symptoms, such as mobility difficulties, limited movement, or significant impact on daily life:

  Intra-articular sodium hyaluronate injections or arthroscopic joint debridement can be considered. These methods help suppress inflammation, relieve pain, and reduce joint damage. A thorough examination and removal of loose bodies or fragmented cartilage can effectively improve joint function^[2].

• Patients with severe clinical symptoms (loss of labor capacity or basic daily living abilities):

  Joint replacement surgery may be performed to effectively restore joint function, correct deformities, and alleviate pain.

How effective is drug treatment for Kashin-Beck disease?

• Nonsteroidal anti-inflammatory drugs (NSAIDs) can effectively reduce inflammation and relieve pain.

  However, they may cause gastrointestinal side effects such as upper abdominal discomfort, nausea, vomiting, loss of appetite, or gastric ulcers. They may also increase the risk of cardiovascular diseases, including heart attacks and strokes, so elderly patients should use them with caution.

• Cartilage-nourishing medications can repair joint cartilage, protect surrounding soft tissues, improve cartilage function, and reduce pain.

DIET & LIFESTYLE

What should patients with Kashin-Beck disease pay attention to in daily life and diet?

In daily life, pay attention to getting more rest and avoid excessive fatigue;

In terms of diet, focus on calcium supplementation by appropriately consuming more dairy products, soy products, vegetables, fish, and seafood. Vitamin D can be appropriately supplemented to promote calcium absorption;

Quit smoking and drinking, and reduce the intake of spicy and greasy foods.

PREVENTION

How to Prevent Kashin-Beck Disease?

• Avoid Exposure to Harmful Factors

  For grains, strictly control every step of harvesting and storage to reduce contamination risks and prevent mold growth. Moldy grains must not be consumed.

  In endemic areas, switching from dry fields to paddy fields, reducing the intake of wheat and corn, and replacing staple foods with rice can minimize exposure to Fusarium-contaminated grains, thereby preventing Kashin-Beck disease.

  Since organic contamination of drinking water is also considered a potential cause, protecting water source environments, using purified tap water, and avoiding untreated unclean water can help prevent exposure to polluted sources.

• Increase Selenium Intake

  Selenium supplementation is effective in preventing Kashin-Beck disease.

  Consume more foods rich in organic selenium, such as fish, shrimp, eggs, garlic, and corn, or opt for selenium-fortified products.

  Increase intake of foods containing vitamins A, C, and E, such as animal liver, fruits, and vegetables, to enhance selenium absorption.

  However, moderation is key—excessive selenium intake can be harmful, so avoid over-supplementation.

• Strengthen Physical Fitness

  Engage in regular exercise, balance work and rest, and maintain a robust physique to ensure normal bodily functions. Diversify your diet to avoid nutritional deficiencies, ensuring comprehensive nutrient intake and boosting immunity.