Risk factors for ovarian cancer: Is there a missing link? S. Sadetzki, F. Modugno, B. Oberman, A. Chetrit, F. Lubin, R. Ness; Chaim Sheba Medical Center, Gertner Institute, Ramat-Gan, Israel; University of Pittsburgh Cancer Institute, Pittsburgh, PA; University of Pittsburgh -School of Public Health, Pittsburgh, PA Abstract: Background: Despite the higher prevalence of BRCA1/2 mutations among Ashkenazi women, ovarian cancer (OvC) incidence among European-American Israeli women is similar to that of Caucasians in the US. Three hypotheses may explain this observation: either Israeli women practice more protective behaviors or Americans are more exposed to risk factors. Alternatively, due to gene-gene or gene-environment interactions, risk factors might affect each population differently. Finally, unidentified risk factors may differ between these populations. Methods: We compared the magnitude and effects of OvC risk factors between Israeli-Jewish and US Pennsylvania women using data from two population-based case-control studies conducted in the 1990s. The Israeli study included 998 cases and 1528 controls individually matched by age and ethnicity. The American group comprised 767 cases frequency matched by age and race to 1367 controls. Both studies used personal interviews to obtain risk factor data. Odds ratios (ORs) adjusted for age, education and race/origin were calculated using logistic regression and compared by Walds Test. Results:Significant differences in the distribution of most study variables were found between the two groups. Israeli women reported more positive family history of OvC, a later age at menarche and menopause, less nulliparity, more livebirths and longer duration of breastfeeding. Oral contraceptive (OC) use and tubal ligation, were significantly more prevalent among US women. Both studies showed consistent results regarding the role of most factors on OvC risk. However, the protective role of OC use and parity was more pronounced in the US (OC use 5+ years vs. never OR= 0.84 and 0.6, p=0.14; livebirth 3+ vs 0 OR= 0.52 & 0.27, p=0.02, Israeli and American groups, respectively). Conclusions: Considering the higher prevalence of genetic risk factors in the Israeli population together with the increased protection for OC use and parity among US women, a modification effect of BRCA1/2 mutations on these factors might exist. Otherwise, these findings might indicate the presence of other unidentified environmental and/or genetic factors that provide increased protection to Israeli women. Abstract No: 5012 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.