Dietary Fat, Fat Subtypes, and Breast Cancer in Postmenopausal Women: a Prospective Cohort Study

Reviewers: Li Liu, MD
Source: Journal of the National Cancer Institute, volume 92, 833-839 (May) 2000

Introduction

High intake of total dietary fat has been postulated to increase breast cancer risk on the basis of animal studies, international comparisons, and some other case-control studies. However, some prospective cohort studies have shown different results. In this study, the researchers investigated the association between total dietary fat and fat subtype intake and breast cancer risk in a large, prospective cohort study of postmenopausal women.

Materials and Methods

Completed surveys on dietary habits were collected from 40,022 postmenopausal women who enrolled in a study of screening mammography between 1987 and 1989.

Results

With an average follow-up of 5.3 years:

• 996 women developed breast cancer.
• Little association was found between intake of total fat or any fat subtype and breast cancer risk in the cohort as a whole.
• In nearly 14,000 women with no prior history of benign breast disease, the risk of developing breast cancer in women in the highest quintile for percentage of energy from total fat was 2.2 fold higher compared with those in the lowest quintile.

Discussion

In this study, no link was found between fat intake and development of breast cancer in postmenopausal women. This finding suggests that reductions in total fat intake during adulthood are unlikely to reduce the risk of breast cancer. A woman's decision about fat intake should be guided primarily by risk of heart disease, which is strongly influenced by the type but not total amount of fat.