[The reproductive function and the risk of developing cancer of the breast in different ethnic groups]

The study was concerned with the relationship between certain characteristics of reproductive case history and risk for breast cancer development in three different ethnic groups of females living in the Moldavian SSR: Moldavians, Ukrainians and Russians. Risk of cancer was found to be higher in all groups in cases of premenstrual syndrome, late onset of sexual life (greater than or equal to 26 years), suspension of sexual life for more than 12 months, late first pregnancy and delivery, low productivity (0-1 birth in case history), agalactia, and menstrual cycle resumption 1-2 months after childbirth. However, certain ethnic differences in relationships between such factors as age of menopause onset, no pregnancies, late pregnancy (greater than or equal to 40 years) and type of contraceptives used and risk of cancer are rather due to the difference in prevalence of said factors in the groups under study. The results of the investigation suggest a common pattern of influence of reproductive case history factors on risk for breast cancer in different ethnic groups.