Objective: Yusho is a 1968 mass food poisoning event caused by the ingestion of rice oil contaminated with dioxins and related organochlorines that induce oxidative stress. Many patients continue to suffer from symptoms. Oxidative stress has been reported to be the pathogenesis for static blood (SB), and we have found many Yusho patients with palmar erythema (PE) and dilatation of the sublingual vein (SV), both signs of SB. Livid tongue is also a sign of SB, and we developed a tongue image analyzing system (TIAS) for the objective recording of tongue color (TC).With TIAS, we previously reported a correlation between the severity of SB and TC(4a*). However, the association between SB and the TC of Yusho patients is unclear. This study was done to clarify the prevalences of PE and dilatation of the SV and used TIAS to determine the relation between PE and dilatation of the SV with the severity of the SB of Yusho patients.

Methods: The data of 132 certified Yusho patients who attended our medical screening was available for analysis. TC was classified by the device-independent international commission on Illumination 976L*a*b* color space standards at four points. PE was classified into three groups: (A) none, (B) partial, and (C) positive and dilatation of the SV into four, (A) none, (B) slightly, (C) moderate, and (D) markedly.

Results: PE and dilatation of the SV were observed in 63.6% (A,19; B,29; C,84) and 100%(B,61;C,63;D,8), respectively. Adjusted for confounding factors, TC (3b*) was significantly associated with PE (positive) and TC (4a*) with dilatation of the SV (moderate and markedly).

Conclusion: Along with our previous finding of an association the severity of SB and TC, observation of dilatation of the SV could be useful in the development of new strategies for targeting the SB of Yusho patients.