Lifestyle-determined gender and hierarchical differences in the lead contamination of bones from a feudal town of the Edo period.

We analyzed lead concentrations in bones from both genders of Japanese merchants (including rohnin; masterless samurai) and farmer classes, and compared the findings with those of the samurai class in the Edo period (1603-1867) to clarify gender and hierarchical (or occupational) differences in lead exposure during the Japanese feudal age. Merchant class females had significantly higher lead exposure (90.8 microg Pb/g dry bone; n=20) than males of the same class (39.9 microg Pb/g dry bone; n=31) (p<0.01), indicating a remarkable gender difference in the urban population. In contrast to these high concentrations, males and females of the farmer class living in agricultural (or semi-rural) areas had significantly lower exposure (total mean value; 9.2 mug Pb/g dry bone; n=4) than both genders of the merchant class (p<0.001), and the gender difference was not significant in this class.