[The risk factors for breast cancer (a prospective controlled study)]

Preliminary results of a prospective study of known risk factors for breast cancer are discussed in the paper. The study included 42,785 females aged 40-64 years who were followed for 2-5 years (mean--3.1 years). Within this period, 146 cases of breast cancer were registered. A significant (p < 0.05) increase in the relative risk (RR) of breast cancer was established for females aged over 50 (50-59 years--RR-1.4; 95% CI--1.0-2.0 and 60-64 years-RR--2.4; 95% CI 1.6-3.7), overweight patients (RR--1.5; 95% CI--1.1-2.1), subjects who developed menopause after the age of 50 (RR--1.6; 95% CI--1.1-2.2) and those with a ten-year or longer history of liver or bile ducts pathologies (RR--1.7; 95% CI--1.1-2.7). The role of certain factors differed significantly in different age groups. At the age of 40-49 years, the RR of breast cancer rose significantly for overweight subjects (RR--2.0; 95% CI--1.2-3.4) and those with liver pathologies (RR--2.5; 95% CI--1.3-4.6), at the age of 50-59-for subjects with late (after the age of 50) menopause (RR--2.0; 95% CI--1.2-3.4) and at the age of 60-64 years-for nulligravidae (RR--2.8; 95% CI--1.1-6.8).