Essential fatty acids and breast cancer: a case-control study in Uruguay.

The relationship between frequency of intake of different types of fat and breast cancer was investigated in a case-control study conducted in Montevideo, Uruguay, during the time period 1994-1996. Our study comprised 365 cases and 397 controls. A moderate and non-significant increase in risk of breast cancer, associated with total fat intake, was found. Saturated and monounsaturated fat intake were not associated to an increased risk of this malignancy, whereas polyunsaturated fat and linoleic acid were associated with a significantly reduced risk (OR 0.26, 95% CI 0.13-0.53). On the contrary, both alpha-linolenic acid and cholesterol intakes were associated with an increased risk of breast cancer (OR for the upper quartile of intake of alpha-linolenic acid 3.79, 95% CI 1.53-9.40). When alpha-linolenic was examined at different levels of intake, the OR's were significantly higher at low levels of linoleic acid intake (OR 7.5, 95% CI 1.9-28.8).