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 ide ntify the risk factors for Kashin-Beck disease in Tibet. Children aged 5-15 years (n=575) were examined and their corresponding houses were visited. S amples were collected in order to study fungal contamination of stored grai n and the organic matter content of drinking water. Multivariate analysis w as performed using logistic regression and population attributable fraction s were computed to estimate the impact of each factor. The following variab les 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 deg ree of fungal contamination of barley grain was related to the highest perc entage of cases (65%) in a sample of the study population. Higher urinary i odine levels were not associated with decreasing prevalence rates when Alte rnaria sp. was isolated. The data that we report supports the hypothesis th at Kashin-Beck disease occurs as a consequence of oxidative damage to carti lage and bone cells when associated with decreased antioxidant defence. Ano ther mechanism that may coexist is bone remodelling stimulated by thyroid h ormones whose actions can be blocked by certain mycotoxins.