Estrogen fractions and breast cancer risk in Canadian Inuit and whites.

Based on a noted lesser incidence of breast cancer among the Inuit population vs. white women in Canada and given the previous findings among other population (e.g. Japanese women) that estriol levels in urinary fractions of these populations are more favorable in addition to the apparent racial similarities (Inuits stock may be Mongoloid) first morning urine specimens of Inuit women in a small community in the High Arctic were assayed for estrogens. These values were compared with a matched white population of Canadian women. No significant differences in estrogen profiles were detected (estriol in Inuit population 12.54 mcg/liter and in the white population it was 20.63 mcg/liter). The estriol proportion was also not significantly different between the 2 study populations (.393 and .427 for Inuit and whites respectively. The hypothesis that the Inuit womans low risk of breast cancer results from a more favorable estriol proportion is not proven by this study. (Summary in FRE)