Epithelial ovarian carcinoma and European birthplace of grandparents

Objective. The aim of this study was to determine whether the risk of ovari an carcinoma was related to latitude or to genetically based patterns of Eu ropean geographic origin. Patients and methods. We studied the countries of origin of European-born g randparents of 168 newly diagnosed patients in two hospitals in New York Ci ty, compared with 159 controls from similar neighborhoods. We measured the risk of this cancer associated with having one or more white, non-Jewish gr andparents born in North Europe versus none or in South Europe versus none. We also classified geographic origins in other ways to reflect the two mai n trends in genetic variations between Europeans mapped by Cavalli-Sforza e t al. (The History and Geography of Human Genes, Princeton University Press , Princeton, 1994). Unconditional logistic regression was used to control f or age, parity, years of use of oral contraception, age at menarche, educat ion, Catholic religion, and area of residence and for numbers of Jewish gra ndparents, siblings, and first-degree relatives with breast or ovarian canc er. Results. Approximately half of the subjects had least one white, non-Jewish grandparent born in Europe. There was no significant effect of ancestral l atitude: among women born in the United States the odds ratio (OR) and 95% confidence limits associated with North European ancestry were 0.87 (0.47-1 .63) compared with a reference group of women with no such ancestry. The co rresponding OR for South Europe was 0.73 (0.39-1.74). Using the genetically based classifications of countries of origin, however, we found significan t differences between cases and controls; ancestries from North West Europe and those from countries concentrically near Spain showed lower risks of o varian carcinoma. Conclusions. The results support the hypothesis that the previously observe d effects of latitude must act through environmental effects or through gen e-environment interactions. Other variations in risk related to geographic origins are consistent with known patterns of genetic differences, but requ ire confirmation in larger, population-based studies. (C) 2001 Academic Pre ss.