FATTY-ACID COMPOSITION OF THE SUBCUTANEOUS ADIPOSE-TISSUE AND RISK OFPROLIFERATIVE BENIGN BREAST DISEASE AND BREAST-CANCER

Background. Studies in animals and geographic correlations across popu lations suggest that fatty acid intake may have a positive relationshi p with breast cancer risk, but analytic epidemiologic studies of fat i ntake have been less supportive. Adipose tissue analysis provides a mo re objective assessment of intakes of fatty acids that are not endogen ously synthesized than do the questionnaire survey methods used in man y epidemiologic studies. Purpose: This case-control study of postmenop ausal women was designed to examine the relationship between fatty aci d composition of subcutaneous adipose tissue and risk of breast cancer and proliferative benign breast disease. In addition, we examined spe cific hypotheses that breast cancer risk is negatively associated with long-chain N-3 fatty acid intake, positively associated with trans fa tty acid intake, and positively associated with increased intake of po lyunsaturated fat together with low intake of antioxidants. Methods: A spirates of subcutaneous fat from the buttocks were obtained from 380 women with newly diagnosed stage I or II breast cancer and 176 with pr oliferative benign breast disease. A total of 397 women who were evalu ated for breast abnormalities at the same institutions but did not req uire breast biopsy or whose biopsy revealed nonproliferative benign br east disease served as the control group. We examined associations bet ween saturated, monounsaturated, polyunsaturated, trans, or long-chain N-3 fatty acids and breast cancer, atypical hyperplasia, or prolifera tive benign breast disease without atypia. Results: We observed no con sistent patterns of association between breast cancer risk and any of the categories of fatty acids or the individual constituent fatty acid s in the adipose tissue. Saturated fatty acids were inversely associat ed with risk of proliferative benign breast disease without atypia but not with atypical hyperplasia or breast cancer. This association was not observed, however, when total fat intake was taken into account. W omen with high levels of polyunsaturated fatty acids in adipose tissue and low serum or dietary levels of antioxidants were not observed to be at higher risk of breast cancer. Conclusions: Using an objective me asure of intake, we observed no major associations between polyunsatur ated fatty acids, including long-chain N-3 fatty acids and trans fatty acids, and risk of breast cancer or proliferative benign breast disea se. Implications: These data do not support the hypothesis that intake of specific fatty acids, particularly polyunsaturated and trans fatty acids, is an important risk factor for malignant or benign breast dis ease.