Background: Since 1968, when the Yusho poisoning incident occurred, annual physical, dermatological, dental, and ophthalmological and laboratory examinations, collectively called Yusho health checks, have been conducted for Yusho patients. The Yusho incident was a health hazard caused by intake of rice-bran oil contaminated with PCB and PeCDF; therefore, since 2001 the levels of dioxins such as PeCDF in the blood have been measured in applicants. Here, we investigated correlations among findings from various medical examinations and those between those findings and PeCDF, PCB, and PCQ.
Patients and methods: Subjects were Yusho patients who underwent Yusho annual health checks and had their levels of PeCDF measured between 2001 and 2004. The results of 4 years of health checks of those who underwent the health checks for 2 years or longer were aggregated to extract representative inspection items by principal component analysis. We also investigated the presence or absence of correlations among these items and PeCDF, PCB, and PCQ levels in blood.
Results: Using 49 variables extracted by principal component analysis as objective variables, we determined that there were correlations between the following combinations: arthralgia, A/G ratio and PeCDF level, ophthalmological symptoms such as excessive eye discharge and PCB level, and total cholesterol, inferior gingival pigmentation and PCQ level.