The past history of diseases and symptoms among the Yusho patients, and its association with blood lipid concentration of 2,3,4,7,8-pentachlorodibenzofuran

A nation-wide questionnaire survey on the past history of diseases and symptoms was conducted in 2005. The questionnaire was administered by mail to the 1258 registered Yusho patients, inguiring about the past incidence of 15 regions of malignant neoplasm, 42 diseases, and 5 symptoms. Out of the 717 patients responded to the questionnaire, 34 patients born after the Yusho outbreak were excluded, leaving 683 patients as the study subjects. Their mean age (SD) was 62.7 (14.0) years, ranging from 39 to 97 years old. Seven percent of the patients acknowledged the past history of malignant neoplasm in one or more regions. More than 40% admitted the past history of dental diseases, pain of joints, numbness of limbs, fatigue, headache, cough and sputum. Osteoporosis and myoma of the uterus, respectively, were reported by 22.8% and 15.6% of women. 14.2% of men reported prostatic hypertrophy. Logistic regression analysis was performed to estimate the association of the past history of diseases with the blood lipid level of 2,3,4,7,8-pentachlorodibenzofuran adjusting for sex and age. In the whole study subjects, 306 patients were measured the PeCDF level once or more in the years from 2001 to 2005. We found statistically significant elevation of the proportion of the patients with the past history of prostatic hypertrophy with increasing blood lipid level of 2,3,4,7,8-PeCDF (P = 0.03). The marginally significant positive association between the proportion of the patients with the past history of hypertension and 2,3,4,7,8-PeCDF was observed (P = 0.06).