Written by Chrystal Moulton, Staff Writer. This study shows that consumption of high fat dairy had a higher occurrence of death due to breast cancer and overall higher rate of mortality.
Studies suggest that there may be a relationship between consumption of dairy products and breast cancer (1-3). However, few studies examine the affect of high fat dairy consumption and recurrence or death from breast cancer. In this particular study (4), researchers wanted to determine whether high fat dairy consumption affects breast cancer post-diagnosis. Researchers examined the association between dairy fat consumption and cancer in 1893 women with invasive breast cancer who were a part of the Life After Cancer Epidemiology (LACE) study.
In the Life After Cancer Epidemiology (LACE) study, 2264 women with early-stage invasive breast cancer were recruited in California and Utah from 1997-2000. Their ages ranged from 18-70 years old. Volunteers were eligible if they were diagnosed with stage I, with tumor size greater than 1cm, II, or IIA. They had to enroll 11-39 months after diagnosis, complete breast cancer treatment with no hormonal therapy, have no history of other cancers in the last 5 years, and have no evidence of breast cancer recurrence. At baseline, women were to complete a comprehensive questionnaire on their diet and again at follow up, 6 years after enrollment. Clinical status of volunteers was acquired through the Kaiser Permanente Northern California (KNPC) Registry for the participants affiliated with the registry or through medical records for participants not associated with the registry. Questionnaires were mailed to participants after April 2005 to determine breast cancer recurrence and medical records were used to verify participant report. Participant deaths were retrieved through KNPC registry or communication with family members. Cause of death was determined by death certificate or physician reviewer when necessary.
In the assessment of dairy consumption both at baseline and 6 year follow-up, women were asked how often they consumed dairy foods in the previous year and how much. They were provided with a medium serving portion size and asked if they consumed a small, medium, or large serving. Dairy products included milk, cheese, dairy desserts, and yogurt. Servings per day of dairy was determined as the sum of each food item multiplied by a factor related to serving size (0.5 small, 1.0 medium, 1.5 large). Additionally, servings per day of low-fat dairy were calculated as the sum of servings of low-fat (1-2%) and nonfat items. Servings per day of high fat dairy were the sum of servings of high fat items reported by each participant. Total servings were computed as the sum of servings of all dairy.
Of the 2264 women, 1893 completed the baseline questionnaire and of them 1513 completed the questionnaire at 6-year follow-up. Of 1893 women, 349 had a recurrence of breast cancer and 372 women died. Of the participants who died, 189 women died of breast cancer (50.8%). They found that low-fat dairy consumption overall was inversely related to death by any or all causes (all-cause mortality); but after accounting for other variables such as BMI, menopausal status, disease severity, treatment, behavior, and other related factors, they found no relationship between low-fat dairy consumption and all-cause mortality, recurrence of breast cancer, or death by breast cancer. On the other hand, high-fat dairy intake was related to all-cause mortality. Those consuming 0.5-1.0 servings/day and >1.0 serving/day of high-fat dairy had higher occurrences of death due to breast cancer (P=.05) and overall higher all-cause mortality (P<0.001).
Source: Kroenke, Candyce H., et al. “High-and low-fat dairy intake, recurrence, and mortality after breast cancer diagnosis.” Journal of the National Cancer Institute (2013): djt027.
© The Author 2013. Published by Oxford University Press. All rights reserved.
Posted August 1, 2013.
Chrystal Moulton BA, PMP, is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Indianapolis, IN.
References:
- Dairy products, calcium intake, and breast cancer risk: a case-control study in China. Zhang CX, Ho SC, Fu JH, et al. Nutr Cancer. 2011;63(1):12-20. doi: 10.1080/01635581.2010.516478.
- Dairy consumption and calcium intake and risk of breast cancer in a prospective cohort: the Norwegian Women and Cancer study. Hjartåker A, Thoresen M, Engeset D, Lund E. Cancer Causes Control. 2010 Nov;21(11):1875-85. doi: 10.1007/s10552-010-9615-5. Epub 2010 Jul 25.
- Dairy consumption and risk of breast cancer: a meta-analysis of prospective cohort studies. Dong JY, Zhang L, He K, Qin LQ. Breast Cancer Res Treat. 2011 May;127(1):23-31. doi: 10.1007/s10549-011-1467-5. Epub 2011 Mar 27.
- High- and low-fat dairy intake, recurrence, and mortality after breast cancer diagnosis. Kroenke CH, Kwan ML, Sweeney C, et al. J Natl Cancer Inst. 2013 May 1;105(9):616-23. doi: 10.1093/jnci/djt027. Epub 2013 Mar 14.
