Anthropometry and clinical features of Kashin-Beck disease in central Tibet.

We compared two different populations living in central Tibet with the purpose of establishing standard values for different anthropometric parameters in a rural population. Later on, these values were used as references for a similar study on a KBD population. One group (KBD) (n=1,246) came from the endemic areas, and the other group, serving as the control population (n=815), came from non-endemic areas. Both groups included children and adults and were of the Mongoloid type; they were farmers or semi-nomads. Height, weight, segment length, joint perimeter, joint diameter, joint movement were recorded. Also more subjective information such as general feeling of tiredness, rapid fatigue at work, work limitation, joint pain, muscle weakness, muscular atrophy, dwarfism, flatfoot, and waddling gate was also collected. Those variables were compared between the two groups.

The anatomical distribution of radiological abnormalities in Kashin-Beck disease in Tibet.

A radiological study of osteoarticular changes in Kashin-Beck Disease (KBD) was undertaken on the appendicular skeleton in 105 patients with KBD, in 31 healthy subjects living in an endemic area and in 30 healthy subjects living in a non-endemic area. The bone age was delayed in all three populations with no significant difference between the three studied Tibetan populations. Radiological changes occur in 56% of patients with KBD, and are usually bilateral. An analysis of the distribution of lesions shows a proximo-distal gradient. The changes are more common in the distal aspect of the limb and the lower limb is involved more commonly than the upper limb. The foot and ankle are involved in 89.5% of cases. The radiological changes and their distribution might be explained by the hypothesis of inhibition of angiogenesis by mycotoxins, exacerbated by chemical and physical environmental factors.

A 4-year study of the mycological aspects of Kashin-Beck disease in Tibet.

In order to clarify the association between mycotoxin-producing fungi in food and Kashin-Beck disease (KBD), we examined the occurrence and contamination levels of fungi in samples of barley grain, from KBD-affected families and from unaffected families in endemic areas. A control area without the occurrence of KBD served as reference. The first results obtained in 1995 showed that total mesophilic fungal contamination of barley grain was consistently higher in families with KBD. Trichothecium roseum (Pers) Link ex gray, Dreschlera Ito and Alternaria Nees ex Fr. were the three most common fungi significantly associated with KBD. In 1996 we again observed a significant difference between affected and non-affected families, especially with Trichothecium roseum and Ulocladium Preuss. On this basis, measures to prevent KBD were suggested and a preventive program has been set up since 1998 in 20 new villages.

The prevalence of mycotoxins in Kashin-Beck disease.

Mycotoxins are naturally occurring toxic chemical compounds produced by fungi infesting agricultural crops both during their growth and storage. Such secondary metabolites, when ingested, can produce toxic syndromes in humans. As it has been suggested that mycotoxins might be involved in the development of Kashin-Beck disease (KBD), we undertook a survey of barley grains of KBD-affected families and non-affected families in that country. We found, by thin layer chromatography, a hitherto unknown metabolite of Alternaria sp. This was especially common on the barley grains of KBD-affected families.

Kashin-Beck disease and iodine deficiency in Tibet.

We evaluated iodine and selenium status in 575 children between 5 and 15 years with Kashin-Beck disease from endemic and non-endemic areas. Of these 267 (46%) children had goiter. The proportion of subjects with goiter was higher in the villages with Kashin-Beck disease than in the control village. In the villages with Kashin-Beck disease, 105 (23%) of the subjects had a serum thyrotropin greater than 10 mU/l as compared with 3 (4%) in the control village. The percentages of low serum thyroxine values and low serum tri-iodothyronine were greater in the villages where Kashin-Beck disease was endemic than in the control village. The percentages of low urinary iodine concentration were significantly greater in the subjects with Kashin-Beck disease. The results suggest that in areas where severe selenium deficiency is endemic, iodine deficiency is a risk factor for Kashin-Beck disease.

Ethno-agricultural approach to the rural environment in the prevention of Kashin-Beck disease.

Kashin-Beck disease occurs in several villages of Tibet; however, its local importance varies greatly. The ecoclimatological as well as the phytogeographical framework of the studied area are presented. An ecological approach based upon the ethno-ecosystem concept was carried out in the vicinity of each village. This study identifies 18 vegetation units on a structural basis; they were named for the dominant plants of each unit. Half of them belonged to the aquatic milieu. The different factors controlling their distribution were also identified. Particular attention will be paid to the links between man and the environment, particularly regarding alternative food intakes and water supply access.

Kashin-Beck disease and drinking water in Central Tibet.

A cross-sectional survey was carried out in order to study the relationship between Kashin-Beck disease and drinking water. The average volume of the water containers was larger in families unaffected by the disease. Organic material was measured by ultraviolet (UV) spectroscopy. The UV absorbency was significantly lower in drinking water of unaffected families. Thus, the organic material in drinking water may play a role in the pathogenesis of Kashin-Beck disease.

Effects of physical therapy on patients with Kashin-Beck disease in Tibet.

A clinical trial of physical therapy treatment for patients suffering from Kashin-Beck disease (KBD) has been carried out in Tibet. One-hundred and thirty-five patients with Kashin-Beck disease were allocated to either physical therapy (72 patients) or prescription of multivitamins (63 patients). The patients were followed for 4 years. This study suggested a beneficial effect of physical treatment.

Epidemiological support for a multifactorial aetiology of Kashin-Beck disease in Tibet.

We carried out a cross-sectional study in 12 rural villages in order to identify the risk factors for Kashin-Beck disease in Tibet. Children aged 5-15 years (n=575) were examined and their corresponding houses were visited. Samples were collected in order to study fungal contamination of stored grain and the organic matter content of drinking water. Multivariate analysis was performed using logistic regression and population attributable fractions were computed to estimate the impact of each factor. The following variables were independently associated with the disease: age, gender, low socio-economic status, indicators of a poorly diversified diet, iodine deficiency and small water container size (with higher organic matter levels in small containers). Selenium deficiency was severe in all study subjects. The degree of fungal contamination of barley grain was related to the highest percentage of cases (65%) in a sample of the study population. Higher urinary iodine levels were not associated with decreasing prevalence rates when Alternaria sp. was isolated. The data that we report supports the hypothesis that Kashin-Beck disease occurs as a consequence of oxidative damage to cartilage and bone cells when associated with decreased antioxidant defence. Another mechanism that may coexist is bone remodelling stimulated by thyroid hormones whose actions can be blocked by certain mycotoxins.

Kashin-Beck osteoarthropathy in rural Tibet in relation to selenium and iodine status.

BACKGROUND AND METHODS: Kashin-Beck disease is a degenerative osteoarticular disorder that is endemic to certain areas of Tibet, where selenium deficiency is also endemic. Because selenium is involved in thyroid hormone metabolism, we studied the relation among the serum selenium concentration, thyroid function, and Kashin-Beck disease in 575 subjects 5 to 15 years of age in 12 villages around Lhasa, Tibet, including 1 control village in which no subject had Kashin-Beck disease. Clinical, radiologic, and biochemical data were collected. RESULTS: Among the 575 subjects, 280 (49 percent) had Kashin-Beck disease, 267 (46 percent) had goiter, and 7 (1 percent) had cretinism. Of the 557 subjects in whom urinary iodine was measured, 66 percent had a urinary iodine concentration of less than 2 microg per deciliter (157 nmol per liter; normal, 5 to 25 microg per deciliter [394 to 1968 nmol per liter]). The mean urinary iodine concentration was lower in subjects with Kashin-Beck disease than in control subjects (1.2 vs. 1.8 microg per deciliter [94 vs. 142 nmol per liter], P<0.001) and hypothyroidism was more frequent (23 percent vs. 4 percent, P=0.01). Severe selenium deficiency was documented in all villages; 38 percent of subjects had serum concentrations of less than 5 ng per milliliter (64 nmol per liter; normal, 60 to 105 ng per milliliter [762 to 1334 nmol per liter]). When age and sex were controlled for in a multivariate analysis, low urinary iodine, high serum thyrotropin, and low serum thyroxine-binding globulin values were associated with an increased risk of Kashin-Beck disease, but a low serum selenium concentration was not. CONCLUSIONS: In areas where severe selenium deficiency is endemic, iodine deficiency is a risk factor for Kashin-Beck disease.

PIP: Selenium is involved in thyroid hormone metabolism. Kashin-Beck disease is a degenerative osteoarticular disorder endemic to certain areas of Tibet, where selenium deficiency is also endemic. Findings are reported from an investigation of the relationship among serum selenium concentration, thyroid function, and Kashin-Beck disease in 575 subjects aged 5-15 years in 12 villages around Lhasa, Tibet, including 1 control village in which no one had Kashin-Beck disease. Clinical, radiologic, and biochemical data were collected. 280 (49%) subjects had Kashin-Beck disease, 267 (46%) had goiter, and 7 (1%) had cretinism. Of the 557 subjects in whom urinary iodine was measured, 66% had a urinary iodine concentration of less than 2 mcg/dl. Mean urinary iodine concentration was lower in subjects with Kashin-Beck disease than in control subjects and hypothyroidism was more frequent. Severe selenium deficiency was documented in all villages, with 38% of subjects having serum concentrations of less than 5 ng/ml. When age and sex were controlled for in a multivariate analysis, low urinary iodine, high serum thyrotropin, and low serum thyroxine-binding globulin values were associated with an increased risk of Kashin-Beck disease, but a low serum selenium concentration was not.

Clinical manifestations of Kashin-Beck disease in Nyemo Valley, Tibet.

Clinical manifestations of Kashin-Beck disease have been studied in Central Tibet. Statistical analysis of physical signs allowed a definition of the clinical diagnosis and a scale for the functional severity for the disease to be drawn up. This classification is used for the assessment of patients who received palliative physical treatment. A group of 136 patients have been examined and their disabled joints classified according to pain, bony enlargement and restriction of movement. 57% were between 20 and 35 years of age. The patients mainly complained about their distal weightbearing joints. The clinical evolution of the disease is described from childhood to adult life.