Breast cancer risk in relation to serum cholesterol, serum beta-lipoprotein, height, weight, and blood pressure.

The relation between breast cancer risk and serum levels of cholesterol and beta-lipoprotein (BLP), height, weight, Quetelet's index and blood pressure was studied in a cohort of 46,570 Swedish women less than 75 years of age. The cohort was examined between 1963 and 1965 and followed up in the Swedish Cancer Registry until 1983. During this period 1,182 cases of breast cancer were reported. Of those, 196 were reported among women less than 50 years of age. Statistically significant positive associations were observed between height, weight, and systolic blood pressure and breast cancer risk. No clear trend in cancer risk related to serum cholesterol or BLP was seen in the total material. In a stepwise Cox multiple regression analysis only the associations with height and blood pressure remained significant. Among women, having their cancer diagnosed before the age of 50, higher Quetelet's index was associated with a lower cancer risk, whereas a positive correlation was seen among women greater than or equal to 50 years. In the group of younger women a high BLP level was associated with an increased risk of breast cancer. This relation became even stronger when studied in a multivariate analysis, which also showed a negative correlation between serum cholesterol and cancer risk.