RISK OF BREAST-CANCER IN RELATION TO BLOOD-LIPIDS - A PROSPECTIVE-STUDY OF 31,209 NORWEGIAN WOMEN

In this prospective study, the relationship between blood lipids and b reast cancer risk was examined. Between 1977 and 1983, 31,209 Norwegia n women, 20 to 54 years of age, attended a health screening carried ou t by the Norwegian National Health Screening Services. The screening c onsisted of a questionnaire, anthropometric measurements, and nonfasti ng blood drawn for analysis of total serum cholesterol (TC), triglycer ide (TG), and high density lipoprotein (HDL) cholesterol. Low density lipoprotein (LDL) cholesterol was calculated by the Friedewald's formu la. During the seven to 13 years of follow-up, 302 breast cancer cases were identified by linkage to the Norwegian Cancer Registry. After ad justment for some of the known risk factors of breast cancer, the rela tive risk of women in the highest quartile of TC compared with women i n the lowest quartile was 0.87 (95 percent confidence interval [CI] = 0.61-1.23). The corresponding relative risks and CIs were 0.82 (CI = 0 .58-1.16) for TG, 1.02 (CI = 0.73-1.42) for HDL, and 0.93 (CI = 0.67-1 .29) for LDL. No association between breast cancer risk and blood lipi ds was found in the total population, nor when the data were divided i nto those diagnosed before or after the age of 50 as a dividing line b etween pre- and postmenopausal diagnosis.