[Dynamic observation on the relationship between the Keshan disease incidence and some element in internal and external environment in Shanxi Province].

Objective: To observe the dynamic changes of condition in Keshan Disease (KSD) and trace element in internal and external environment.

Methods: Based on the standard of KSD surveillance and diagnosis, surveillances site of KSD was set up in Huangling country and all local residents were listed as surveillance subjects. Dynamic changes of condition in KSD were observe. Meanwhile, the hair samples of children and cereals in surveillances sites were selected, and the content of Se, Cu, Ze, Fe and Mn in above samples were determined by atomic absorption spectrometry and fluorospectrophotometry respectively.

Results: (1) There were 447 cases of Latent KSD were diagnosed during 15 years. The incidence rates of KSD among people mainly monitored were 3.6%-10.9%. (The average incidence rate was 6.14%). The incidence rates of KSD were risen slowly and were reached steadily. The numbers of new diagnosed cases of latent KSD were 25. The new incidence rates were 0-55.6/ten thousand. The average incidence rate was 34.34/ten thousand, which was decreased slowly. (2) The Se level of wheat in endemic area was significantly lower than that in non-endemic, the hair Se level of children in endemic area was risen yearly and could already reach and steadily stabilize with non-endemic since 1995. Hair Fe level of children in endemic area was significantly higher than that in non-endemic.

Conclusion: The decline and stabilization of KSD could be associated with increase of Se level in inside environment among the residents in endemic area. However, even if the Se level in inside environment of residents in endemic area could reach the level in non-endemic area, new cases of latent KSD patients were still found in these areas, which suggested that Se could be an important factor that can cause KSD rather than the only factor.