Françoise Begaux

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.

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

Summary. 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.Résumé. Les signes cliniques de la maladie de Kashin-Beck (KBD) sont étudiés dans le Tibet central. L’analyse statistique des symptômes a permis aux auteurs de mieux définir le diagnostic clinique évoqué dans la littérature et de proposer une classification fonctionnelle de l’évolution de la maladie. Cette classification sera utilisée ultérieurement pour l’évaluation des patients KBD qui recevront un traitement de kinésithérapie. La distribution des cas est étudiée en fonction de l’âge, du sexe et de la gravité. Les articulations atteintes sont classées en fonction des principales manifestations cliniques: la douleur, l’élargissement des articulations et la limitation de l’amplitude articulaire. Cinquante-sept pour cent des cas étudiés sont de jeunes adultes (20 à 35 ans). Les symptômes principaux sont très constants. Les plaintes dominantes des patients ont pour origines les articulations distales des membres inférieurs. L’évolution clinique est décrite depuis l’enfance jusqu’à l’âge adulte.

Fungal contamination in barley and Kashin-Beck disease in Tibet

5First results showed that mesophilic fungal contaminations were significantly higher on barley grains stored in families with KBD (median 66% of grains infected) than in healthy families (median 43% of grains infected) (Kruskal-Wallis p<0·01). The risk of KBD associated with the presence of fungal taxa on barley grains was expressed in odds ratios (ORs), adjusted for age and sex and calculated with logistic regression. Three common fungal taxa in grains were significantly associated with KBD. Trichothecium roseum (Pers) Link ex Gray (OR16·37, p<0·001), Dreschlera Ito (OR8·75, p<0·001) and Alternaria Nees ex Fr (OR2·96, p<0·001). ORs adjusted for the presence of other fungi concerned showed an independent effect of each of these three taxa. However the effect of Dreschlera was significantly higher in presence of a fourth taxon. Cladosporium Link ex Fr, indicating an interaction (p<0·05). Compared with the absence of fungi, the cumulative effect of different fungal associations can be estimated (figure). On the basis of these results, we conclude that, in Tibet, there are two critical periods for fungal grain contamination related to KBD. First, during the growing season, from contaminated seeds (Dreschlera) or from contaminated debris of the preceding harvest (Alternaria, Cladosporium). Second, just after harvest, during the drying period in the field, especially when the daily difference of temperature is high (dewy grains) and consequently, at the beginning of the storage, when too moist grains are placed in bags or other containers (Trichothecium roseum and also Alternaria and Cladosporium). As measures to prevent KBD in Tibet, we suggest disinfection of barley seeds, destruction of crop residues, and efficient grain drying before storage.

Mycotoxins in Stored Barley (Hordeum vulgare) in Tibet Autonomous Region (People's Republic of China)

Abstract Mycotoxins are naturally occurring toxic chemical compounds produced by fungi infesting agricultural crops both during crop growth and storage. Such secondary metabolites, when ingested, can produce toxic syndromes in humans. This study is the first survey that documents the occurrence of mycotoxins in stored barley in Tibet Autonomous Region [P.R. China]. Twenty-five samples of barley collected from Tibet were analyzed for the presence of aflatoxins, fumonisins, ochratoxins, zearalenone, deoxynivalenol, and T-2 toxin using an easy, sensitive, competitive direct enzyme-linked immunosorbent assay. Ninety-six percent of the samples were contaminated with zearalenone at concentrations ranging from 25 to 270 µg/kg. Seventy-six percent of the samples were contaminated with T-2 toxin at concentrations ranging from 1 to 163 µg/kg. In contrast, deoxynivalenol was observed in only 12% of the samples, with toxin concentrations ranging from 25 to 270 µg/kg. Aflatoxin was observed in only 4% of the contaminated samples.