TISSUE STORES OF INDIVIDUAL MONOUNSATURATED FATTY-ACIDS AND BREAST-CANCER - THE EURAMIC STUDY

The strongest evidence that monunsaturated fat may influence breast ca ncer risk comes from studies of southern European populations, in whom intake of oleic acid sources, particularly olive oil, appears protect ive. No previous study has examined the relation of adipose tissue fat ty acid content to breast cancer in such a population. We used adipose biopsies with diverse fat intake patterns gathered in 5 European cent ers, including southern Europe (Malaga, Spain), to test the hypothesis that stores of oleic acid or other monounsaturates are inversely asso ciated with breast cancer. Gluteal fat aspirates were obtained from 29 1 postmenopausal incident breast cancer patients and 351 control subje cts, frequency-matched for age and catchment area. Logistic regression was used to model breast cancer by monounsaturates, with established risk factors controlled for. Oleic acid showed a strong inverse associ ation with breast cancer in the Spanish center. The odds ratio for the difference between 75th and 25th percentiles was 0.40 (95% CI: 0.28, 0.58) in Malaga and 1.27 (0.88, 1.85) in all other centers pooled, wit h a peak at 2.36 (1.01, 5.50) for Zeist. Palmitoleic and myristoleic a cids showed evidence of an inverse association outside Spain, and cis- vaccenic acid showed a positive association in 3 centers. These data d o not support the hypothesis that increasing tissue stores of oleic ac id are protective against breast cancer in non-Spanish populations, Th is finding implies that the strong protective associations reported fo r olive oil intake in dietary studies may be due to some other protect ive components of the oil and not to the direct effect of oleic acid u ptake. Alternatively, high olive oil intake may indicate some other pr otective aspect of the lifestyle of these women.