Positive Health Online

Abstract

MURFF and COLLEAGUES, Department of Medicine, Vanderbilt Epidemiology Center and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37203-1738, USA. harvey.j.murff@vanderbilt.edu  investigated the association of dietary polyunsaturated fatty acids (PUFAs) and the ratio of n-6 PUFAs to marine-derived n-3 PUFAs with breast cancer risk in the Shanghai Women's Health Study.

Background

Breast cancer is the most common cancer in women. Controversy exists regarding the role of dietary fat in breast cancer aetiology.

Methodology

The authors investigated the association of dietary polyunsaturated fatty acids (PUFAs) and the ratio of n-6 PUFAs to marine-derived n-3 PUFAs with breast cancer risk in the Shanghai Women's Health Study, a prospective cohort study including 72,571 cancer-free participants at baseline. Dietary fatty acid intake was determined using food frequency questionnaires. The authors used Cox proportional hazards analysis to estimate the relative risks (RRs) and 95% confidence intervals (CIs) for the association of breast cancer risk with dietary fatty acids consumption.

Results

In 583,998 person-years of follow-up, the authors identified 712 breast cancer cases. The authors found no association of breast cancer risk to dietary intake of linoleic acid, arachidonic acid, alpha-linolenic acid or marine-derived n-3 PUFA. The authors found a statistically significant interaction between n-6 PUFA intake, marine-derived n-3 PUFA intake and breast cancer risk (p = 0.008). Women with lower intake (the lowest tertile) of marine-derived n-3 PUFA and higher intake (the highest tertile) of n-6 PUFA had an increased risk for breast cancer (RR = 2.06; 95% CI = 1.27-3.34) compared to women with higher intake (the highest tertile) of marine-derived n-3 PUFAs and lower intake (the lowest tertile) of n-6 PUFAs after adjusting for potential confounders.

Conclusion

The relative amounts of n-6 PUFA to marine-derived n-3 PUFAs may be more important for breast cancer risk than individual dietary amounts of these fatty acids.

References

Murff HJ, Shu XO, Li H, Yang G, Wu X, Cai H, Wen W, Gao YT and Zheng W. Dietary polyunsaturated fatty acids and breast cancer risk in Chinese women: a prospective cohort study. International Journal of Cancer. 128(6): 1434-41. Mar 15 2011.

Comment

This research quantified that there was a 26% higher risk of breast cancer for the women in the Shanghai Women’s Health Study with the highest intake of n-6 and lowest intake of marine-derived n-3 polyunsaturated fatty acids (PUFAs), compared to women with the highest intake of n-3 PUFAs and lowest intake of n-6 PUFAs.