In 1986 a prospective cohort study on diet and cancer was started in the Netherlands among 62,573 women ages 55–69 years. Baseline information on diet and other risk factors was collected with a questionnaire. Cancer incidence was measured by record linkage with cancer registries and a pathology register. A case-cohort approach was used, in which the accumulated person time in the cohort was estimated by follow-up of a randomly selected subcohort (n = 1812). After 3.3 years of follow-up, 471 incident breast cancer cases were available for analysis. Questionnaire data for these cases and the 1716 female subcohort members without a history of cancer other than skin cancer were analyzed. In a multivariate analysis, controlling for traditional risk factors, the relative rates for breast cancer in increasing quintiles of energy-adjusted total fat intake were 1.00, 1.00, 1.34, 1.22, 1.08 (P-trend, 0.32). For saturated fat there was some evidence for a weak positive association when quintiles were used (relative rates in quintiles 1–5, 1.00, 1.22, 1.22, 1.38, 1.39; P-trend, 0.049). The 95% confidence interval (CI) for the top quintile was 0.94–2.06, however; and when saturated fat was used as a continuous variable, the effect was no longer significant (P = 0.20). Relative rate estimates for the highest versus lowest quintiles of monounsaturated fat, polyunsaturated fat, and cholesterol intake were 0.75 (95% CI, 0.50–1.12), 0.95 (95% CI, 0.64–1.40) and 1.09 (95% CI, 0.74–1.61), respectively, with no evidence for significant trends. This prospective study does not support a major role of dietary fat in the etiology of postmenopausal breast cancer.


Supported by the Dutch Cancer Society and the Ministry of Welfare, Public Health and Cultural Affairs.

This content is only available via PDF.