CONSUMPTION OF OLIVE OIL AND SPECIFIC FOOD GROUPS IN RELATION TO BREAST-CANCER RISK IN GREECE

Background: Experimental animal studies suggest that olive oil consump tion, as contrasted to consumption of other fat types, does not enhanc e the occurrence of chemically induced mammary tumors, but human data are sparse, Furthermore, evidence is inconclusive concerning the role of food groups, as distinct from that of major nutrients, in the etiol ogy of breast cancer in women, Purpose: This analysis was conducted to evaluate and quantify the effect of consumption of olive oil, margari ne, and a range of food groups on the risk of breast cancer, Methods: Data from a comprehensive, semiquantitative food-frequency questionnai re administered to 820 women with breast cancer and 1548 control women from the study base were used to calculate odds ratios (ORs) and X st atistics of linear trend for the consumption of olive oil, margarine, and a series of food groups classified in quintiles, Adjustment for th e effects of reproductive risk factors, energy intake, and mutual conf ounding influences was implemented through unconditional logistic regr ession modeling, Results: Vegetable consumption and fruit consumption were independently associated with statistically significant reduction s of breast cancer risk by 12% and 8%, respectively, per quintile incr ease; no significant associations were evident for the other food grou ps examined, Increased olive oil consumption was associated with signi ficantly reduced breast cancer risk (OR = 0.75 [95% confidence interva l = 0.57-0.98] for more than once a day versus once a day), whereas in creased margarine consumption was associated with significantly increa sed risk (OR = 1.05 [95% confidence interval = 1.00-1.10] for an incre ment of four times a month), The olive oil association was apparently concentrated among postmenopausal women, but the relevant interaction term was not statistically significant; there was no suggestion of int eraction with menopausal status for consumption of either vegetables, fruits, or margarine, Conclusions: Although major categories of macron utrients do not show significant associations with breast cancer risk in most studies, including the present one, vegetables and fruits are inversely, significantly, and strongly associated with this risk, Ther e also is evidence that olive oil consumption may reduce the risk of b reast cancer, whereas margarine intake appears to be associated with a n elevated risk for the disease.