Dietary Fat, Cooking Fat, and Breast Cancer Risk in a Multiethnic Population

Abstract

Our objective was to examine the association between dietary fat intake, cooking fat usage, and breast cancer risk in a population-based, multiethnic, case-control study conducted in the San Francisco Bay area. Intake of total fat and types of fat were assessed with a food frequency questionnaire among 1,703 breast cancer cases diagnosed between 1995 and 1999 and 2,045 controls. In addition, preferred use of fat for cooking was assessed. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). High fat intake was associated with increased risk of breast cancer (highest vs. lowest quartile, adjusted OR = 1.35, 95% CI = 1.10–1.65, P _trend < 0.01). A positive association was found for oleic acid (OR = 1.55, 95% CI = 1.14–2.10, P _trend < 0.01) but not for linoleic acid or saturated fat. Risk was increased for women cooking with hydrogenated fats (OR = 1.58, 95% CI = 1.20–2.10) or vegetable/corn oil (rich in linoleic acid; OR = 1.30, 95% CI = 1.06–1.58) compared to women using olive/canola oil (rich in oleic acid). Our results suggest that a low-fat diet may play a role in breast cancer prevention. We speculate that monounsaturated trans fats may have driven the discrepant associations between types of fat and breast cancer.

ACKNOWLEDGMENTS

This research was supported by Grants R01 CA63446 (to E. M. John) and R01 CA77305 (to E. M. John) from the National Cancer Institute, DAMD17–96–6071 (to E. M. John) from the United States Army Medical Research Program, and IRB0125 (to P. L. Horn-Ross) and 7WB-0110 (to S. A. Ingles) from the California Breast Cancer Research Program.

Notes

^a Subjects for some variables may not add up to 3,748 due to missing data. Abbreviations are as follows: OR, odds ratio; CI, confidence interval; HRT, hormone replacement therapy; BMI, body mass index.

^b n = 1,703.

^c n = 2,045.

^d OR and 95% CI adjusted for age and race/ethnicity.

^e In first-degree relatives.

^f Number of full-term pregnancies.

^a Abbreviations are as follows: OR, odds ratio; CI, confidence interval.

^b Adjusted for age, race/ethnicity, menopausal status, country of birth, education, family history of breast cancer, history of benign breast disease, age at menarche, parity, breast feeding, BMI, height, and alcohol intake.

^c Model 1: Adjusted for covariates in footnote b and total energy intake.

^d Model 2: Adjusted for covariates in Model 1 and saturated fat, linoleic acid, and oleic acid in a single model.

^a Abbreviations are as follows: OR, odds ratio; CI, confidence interval.

^b Adjusted for covariates in Model 1 of Table 3, with exclusion of race/ethnicity.

^c Adjusted for covariates in Model 2 of Table 3, with exclusion of race/ethnicity.

^a Abbreviations are as follows: OR, odds ratio; CI, confidence interval, ER, estrogen receptor; PR, progesterone receptor.

^b Adjusted for covariates in Model 1 of Table 3, with exclusion of stratified variables.

^c Adjusted for covariates in Model 1 of Table 3 and simultaneously adjusted for saturated fat, linoleic acid, and oleic acid intake as continuous variables (5% of energy).

^d In first-degree relatives.

^e P _int < 0.01.

^f P _int = 0.04.

^g P _int = 0.05.

^a A total of 12 cases and 12 controls had missing data on cooking fat. Abbreviations are as follows: OR, odds ratio; CI, confidence interval.

^b Adjusted for the same covariates as Model 1 in Table 3, with exclusion of race/ethnicity in race/ethnicity specific analysis.

^c Hydrogenated fat included margarine, low-fat margarine, and vegetable oil shortening.

^d Includes subjects choosing vegetable or corn oil only, vegetable or corn oil and olive or canola oil, and vegetable or corn oil and butter or lard.

^e Includes subjects choosing hydrogenated fat only, hydrogenated fat and olive or canola oil, hydrogenated fat and vegetable or corn oil, and hydrogenated fat and butter or lard.

^f Includes subjects choosing Pam or no oil, butter or lard only, and butter or lard and olive or canola oil.