Kashin-Beck Disease - Kashin-Beck Disease Fund asbl-vzw

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Kashin-Beck Disease

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Kashin-Beck Disease

Kashin-Beck disease (KBD), also known as ‘Big Bone Disease’ is a disabling disease of the bones and joints that leads to stunted growth and deformity of the joints. It mainly affects remote, rural populations and been Aetiology and risk factors

The aetiology of KBD remains controversial. Studies on the pathogenesis and risk factors of KBD proposed selenium deficiency, inorganic (manganese, phosphate...) and organic matter (humic acids and fulvic acids) in drinking water, fungi on self-produced storage grain (Alternaria sp., Fusarium sp.), producing trichotecene (T2) mycotoxins.

Nowadays, most authors accept that the aetiology of KBD is multifactorial, selenium deficiency being the underlying factor that predisposes the target cells (chondrocytes) to oxidative stress from free-radical carriers such as mycotoxins in storage grain and fulvic acid in drinking water.

In Tibet, epidemiological studies carried out in 1995-1996 by MSF and coll. showed that  KBD was associated with iodine deficiency and with fungal contamination of barley grains by Alternaria sp., Trichotecium sp., Cladosporium sp. and Drechslera sp (Chasseur et al., 1997). Indications existed as well with respect to the role of organic matters in drinking water.

A severe selenium deficiency was documented as well, but selenium status was not associated with the disease, suggesting that selenium deficiency alone could not explain the occurrence of KBD in the villages under study (Moreno-Reyes et al., 1998)

reported in 13 provinces and 2 autonomous regions of China as well as in Siberia and North Korea. The disease’s aetiology is not yet fully understood, but medical researchers believe it is related to micronutrient deficiencies in food and to fungal contamination of stored grains.

In 1992, Médecins Sans Frontières-Belgium collaborated with local authorities in the TAR in a research project to learn more about the disease, to test prevention strategies and to offer physiotherapy and other forms of physical rehabilitation to people who suffer from it. However, MSF Belgium later closed its programme in the TAR. The Kashin-Beck Disease Foundation asbl-vzw (KBDF) was established in Belgium in 2002 by people who had worked on the MSF project, to carry on the work that had begun in Tibet.

The foundation concentrates especially on improving the nutrition and health of children in areas where the disease is endemic. Activities include providing micronutrient supplements to children in vulnerable families, and large-scale grain decontamination efforts. KBDF also monitors the disease in China, promotes public awareness and understanding of it, and seeks to mobilise new research, prevention and remedial initiatives


Definition and clinical features

Kashin-Beck disease is a permanent and disabling osteoarticular disease involving growth and joint cartilage. Clinical manifestations appear at the age of 5 years. An increasing number of joints become affected during childhood and up to the age of 25 years. Affected individuals present with joint destruction which produces recurrent and mainly bilateral joint pain, with restriction of movement and joint enlargement. The most frequently involved joints are the ankles, knees, wrists and elbows. Severely affected cases are characterised by disproportionate stunted growth with associated joint deformity. Both for adults and children, the resulting disability causes an important human and socio-economic burden in affected villages (Mathieu et al., 1997).


Distribution on Kashin-Beck Disease


Kashin-Beck disease occurrence is limited to 13 provinces and 2 autonomous regions of China. It has also been reported in Siberia and North Korea, but incidence in these regions is reported to have decreased with socio-economic development. In China, KBD is estimated to affect some 2 to 3 million people across China, and 30 million are living in endemic areas. Life expectancy in KBD regions has been reported to be significantly decreased in relation to selenium deficiency and Keshan disease (endemic juvenile dilative cardiomyopathia).  

The prevalence of KBD in Tibet varies strongly according to valleys and villages.

Prevalence of clinical symptoms suggestive of KBD reaches 100 % in 5-15 years old children in at least one village. Prevalence rates of over 50% are not uncommon. A clinical prevalence survey carried out in Lhasa prefecture yielded a figure of 11.4% for a study population of approximately 50 000 inhabitants. As in other regions of China, farmers are by far the most affected population group.

Aetiology and risk factors


The aetiology of KBD remains controversial. Studies on the pathogenesis and risk factors of KBD proposed selenium deficiency, inorganic (manganese, phosphate...) and organic matter (humic acids and fulvic acids) in drinking water, fungi on self-produced storage grain (Alternaria sp., Fusarium sp.), producing trichotecene (T2) mycotoxins.
Nowadays, most authors accept that the aetiology of KBD is multifactorial, selenium deficiency being the underlying factor that predisposes the target cells (chondrocytes) to oxidative stress from free-radical carriers such as mycotoxins in storage grain and fulvic acid in drinking water.

In Tibet, epidemiological studies carried out in 1995-1996 by MSF and coll. showed that KBD was associated with iodine deficiency and with fungal contamination of barley grains by Alternaria sp., Trichotecium sp., Cladosporium sp. and Drechslera sp (Chasseur et al., 1997). Indications existed as well with respect to the role of organic matters in drinking water.
A severe selenium deficiency was documented as well, but selenium status was not associated with the disease, suggesting that selenium deficiency alone could not explain the occurrence of KBD in the villages under study (Moreno-Reyes et al., 1998)


Treatment


Treatment of KBD is so far palliative. Surgical corrections have been made with success by Chinese and Russian orthopaedists. By the end of 1992, Médecins Sans Frontières - Belgium started a physical therapy programme aiming at alleviating the symptoms of KBD patients with advanced joint impairment and pain (mainly adults), in Nyemo county, Lhasa prefecture. Physical therapy had significant effects on joint mobility and joint pain in KBD patients. Later on (1994 - 1996), the programme has been extended to several other counties and prefectures in Tibet.


Prevention on Kashin-Beck disease

Prevention of Kashin-Beck Disease has a long history. Intervention strategies were mostly based on one of the three major etiologic theories.

Selenium supplementation, with or without additional antioxidant therapy (Vitamin E and Vitamin C) has been reported to be successful, but in other studies no significant decrease could be shown compared to a control group. Major drawbacks of selenium supplementation are logistic difficulties (daily or weekly intake, drug supply), potential toxicity (in case of less controlled supplementation strategies), associated iodine deficiency (that should be corrected before selenium supplementation in order to prevent further deterioration of thyroid status) and low compliance. The latter was certainly the case in Tibet, where a selenium supplementation has been implemented from 1987 to 1994 in areas of high endemicity.

With the mycotoxin theory in mind, backing of grains before storage was proposed in Guanxhi province, but results are not reported in international literature. Changing from grain source has been reported to be effective in Heilongjang province and North-Korea.

With respect to the role of drinking water, changing of water sources to deep well water has been reported to decrease the X-ray metaphyseal detection rate in different settings.

In general, the effect of preventive measures however remains controversial, due to methodological problems (no randomised controlled trials), lack of documentation.

 
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