[The temporal change rate of 2,3,4,7,8-PCDF level among examinees of annual health checkups of Yusho].

BACKGROUND Yusho is an incidence of food poisoning caused by rice bran oil in 1968. Its main causal agent is considered as 2,3,4,7,8-penta-chlorodibenzofuran (PeCDF). The patients have been suffered by the various symptoms, and their blood concentration of PeCDF is still higher than the general population. OBJECTIVES The purpose of this study is to estimate the change rate of PeCDF concentration among the examinees of annual health examination of Yusho patients. RESULTS AND CONCLUSIONS PeCDF concentration of 118 men and 140 women who received the health examination four times or more from 2001 to 2008 was statistically analyzed. The estimated annual change rate of the PeCDF concentration was low; 1.43% reduction and 1.03% increase were observed, respectively, for men and women who have low PeCDF concentration, and 3.6% and 3.7% reductions, respectively, for men and women who have high concentration of PeCDF. The reduction rate was associated with age and smoking habit in men, and drinking habit in women.