Int J Epidemiol 2002 Feb;31(1):78-85

Meat and dairy food consumption and breast cancer: a pooled analysis of cohort studies.

Missmer SA, Smith-Warner SA, Spiegelman D, Yaun SS, Adami HO, Beeson WL, van den Brandt PA, Fraser GE, Freudenheim JL, Goldbohm RA, Graham S, Kushi LH, Miller AB, Potter JD, Rohan TE, Speizer FE, Toniolo P, Willett WC, Wolk A, Zeleniuch-Jacquotte A, Hunter DJ.

Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115-6096, USA. stacey.missmer~channing.harvard.edu

BACKGROUND: More than 20 studies have investigated the relation between meat and dairy food consumption and breast cancer risk with conflicting results. Our objective was to evaluate the risk of breast cancer associated with meat and dairy food consumption and to assess whether non-dietary risk factors modify the relation. METHODS: We combined the primary data from eight prospective cohort studies from North America and Western Europe with at least 200 incident breast cancer cases, assessment of usual food and nutrient intakes, and a validation study of the dietary assessment instrument. The pooled database included 351,041 women, 7379 of whom were diagnosed with invasive breast cancer during up to 15 years of follow-up. RESULTS: We found no significant association between intakes of total meat, red meat, white meat, total dairy fluids, or total dairy solids and breast cancer risk. Categorical analyses suggested a J-shaped association for egg consumption where, compared to women who did not eat eggs, breast cancer risk was slightly decreased among women who consumed < 2 eggs per week but slightly increased among women who consumed > or = 1 egg per day. CONCLUSIONS: We found no significant associations between intake of meat or dairy products and risk of breast cancer. An inconsistent relation between egg consumption and risk of breast cancer merits further investigation.

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Am J Epidemiol 2002 Jul 1;156(1):22-31

Dietary fat intake and ovarian cancer in a cohort of US women.

Bertone ER, Rosner BA, Hunter DJ, Stampfer MJ, Speizer FE, Colditz GA, Willett WC, Hankinson SE.

Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA. eberstone~schoolph.umass.edu

Several studies have suggested that high intake of fats and fat-rich foods may increase the risk of ovarian cancer. The authors examined these relations in the Nurses' Health Study cohort. Dietary intake was assessed in 1980, 1984, 1986, and 1990 by using a self-administered food frequency questionnaire. Food data were used to calculate intake of various fats and fatty acids. For best reflection of long-term intake, an updated, cumulative, averaged measure of fat intake was used to predict incidence of ovarian cancer. Between 1980 and 1996, 301 incident cases of invasive epithelial ovarian cancer were confirmed among the 80,258 participants who completed the baseline food frequency questionnaire. There was no evidence of a positive association between intake of any type of fat and ovarian cancer risk, even after adjustment of fat subtypes for one another. Women in the highest quintile of total fat intake were not at increased risk compared with those in the lowest quintile (multivariate relative risk = 1.03, 95 percent confidence interval: 0.72, 1.45, p for trend = 0.97). Intakes of fat-rich foods were also not appreciably associated with ovarian cancer risk, although an increase in risk with frequent intake of eggs was observed. Overall, results suggest no association between intake of any type of fat and ovarian cancer.