Journal of Environmental and Public Health Table 4: The results of logistic regression analysis regarding the sex diﬀerence of the forms of ﬁsh consumed. Men Women OR (95% CI)∗1 Raw ﬁsh Fish-paste products Dry ﬁsh Weekly ﬁsh consumption −1 2+ −1 2+ −1 2+ N 4 96 76 24 54 46 N 14 169 144 39 46 65 1 (reference) 2.0 (0.6–6.0) 1 (reference) 1.1 (0.6–2.0) 1 (reference) 1.5 (0.9–2.5) 5 P = 0.230 P = 0.756 P = 0.092 ∗1 : When calculating P values, age was always included in the models as a covariate. consumption of ﬁsh or ﬁsh products, which contain only a small portion of inorganic mercury. Since inorganic mercury is poorly absorbed through digestive tracts, most of mercury in red blood cells is methyl mercury [5]. Another reason for measuring total mercury is its smaller measurement errors when compared to the measurements of methyl mercury and inorganic mercury. 6. Limitation The mercury levels and n3-PUFA levels are diﬀerent in dif- ferent ﬁsh species. Our question did not include the details of the ﬁsh. Our study area is a small community where ﬁshery is one of the major industries. Inhabitants, particularly, the families of ﬁshermen and those working in ﬁshing industry tend to eat locally caught small-sized ﬁsh (and its products), which tend to be placed low in the food chain and therefore has relatively low mercury concentrations [30]. On the other hand, as for the rest of inhabitants, they have more oppor- tunity to take mercury-rich ﬁsh, such as tunas, because these ﬁsh are supplied anywhere and all the year around (Japanese Ministry of Agriculture, Forestry and Fisheries white paper 2003). We asked ﬁsh frequency. He et al. [31] reported that the ﬁsh intake frequency increased the n3-PUFA intake from ﬁsh [31]. In other words, it is expected that the ﬁsh frequency reﬂects the amount of ﬁsh. We did not use same question- naire of He. However, it is possible to expect that our ﬁsh frequency reﬂects ﬁsh amount to some extent. Both methyl mercury and persistent organic pollutants (POPs) are a group of persistent environmental chemicals. They are found in every level of the food chain. Particularly, these chemicals accumulate in humans mostly through ﬁsh and shellﬁsh. From the nutritional viewpoint, ﬁsh is recom- mended because it is rich is n3-PUFA. Therefore, from the perspective of risk assessment, the above health hazard issues are particularly important in ﬁsh-eating populations [32, 33]. In the present study, we discussed only methyl mercury. It was desirable to have measured POPs. 7. Conclusion The present study showed that ﬁsh consumption is not always related to blood mercury levels and EPA. Those ﬁnd- ings suggest that the health beneﬁt of ﬁsh consumption can be maximized by the careful selection of ﬁsh species consu- med. References [1] Y. Yamori, Y. Nara, S. Mizushima, M. Sawamura, and R. Horie, “Nutritional factors for stroke and major cardiovascular dise- ases: international epidemiological comparison of dietary pre- vention,” Health Reports, vol. 6, no. 1, pp. 22–27, 1994. [2] H. Iso, K. M. Rexrode, M. J. Stampfer et al., “Intake of ﬁsh and omega-3 fatty acids and risk of stroke in women,” Journal of the American Medical Association, vol. 285, no. 3, pp. 304–312, 2001. [3] D. Mozaﬀarian, A. Ascherio, F. B. Hu et al., “Interplay between diﬀerent polyunsaturated fatty acids and risk of coronary heart disease in men,” Circulation, vol. 111, no. 2, pp. 157–164, 2005. [4] S. Akiba, J. Wakamiya, T. Ando, M. Yamamoto, T. Shiraishi, and Y. Kinjo, “Glove-and-stocking type sensory disturbances in a general population—a preliminary report of a study in Amami islands,” Japan: Environmental Sciences, vol. 6, pp. 93– 97, 1998. [5] T. W. Clarkson, “The three modern faces of mercury,” Envi- ronmental Health Perspectives, vol. 110, no. 1, pp. 11–23, 2002. [6] M. M. Storelli, R. Giacominelli-Stuﬄer, A. Storelli, and G. O. Marcotrigiano, “Accumulation of mercury, cadmium, lead and arsenic in swordﬁsh and blueﬁn tuna from the Mediterranean Sea: a comparative study,” Marine Pollution Bulletin, vol. 50, no. 9, pp. 1004–1007, 2005. [7] H. D. A. Kehrig, T. G. Seixas, E. A. Palermo et al., “The rela- tionships between mercury and selenium in plankton and ﬁsh from a tropical food web,” Environmental Science and Pollution Research, vol. 16, no. 1, pp. 10–24, 2009. [8] M. Kainz, K. Telmer, and A. Mazumder, “Bioaccumulation patterns of methyl mercury and essential fatty acids in lacus- trine planktonic food webs and ﬁsh,” Science of the Total Envi- ronment, vol. 368, no. 1, pp. 271–282, 2006.