ATLANTA -- A healthy diet may reduce the risk of ovarian cancer in African-American women, according to data presented at the Eighth American Association for Cancer Research (AACR) Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held Nov. 13-16.
"Because there is currently no reliable screening available for ovarian cancer, most cases are diagnosed at advanced stages," said the study's author, Bo (Bonnie) Qin, PhD, a postdoctoral associate at Rutgers Cancer Institute of New Jersey. "That highlights a critical need for identifying modifiable lifestyle factors, including dietary interventions."
Ovarian cancer is the fifth leading cause of cancer death among women in the United States. African-American women are less likely than white women to be diagnosed with the disease, but more likely to die from it. In order to assess whether an improved diet could reduce the risk of ovarian cancer in African-American women, Qin analyzed the diets of 415 women with ovarian cancer and 629 control patients, using data from the African-American Cancer Epidemiology Study, a population-based case-control study of ovarian cancer in African-American women in 11 sites in the United States.
Qin; her mentor Elisa V. Bandera, MD, PhD, professor of epidemiology at Rutgers Cancer Institute of New Jersey; and fellow researchers evaluated the impact of three index-based dietary patterns: the 2005 Healthy Eating Index (HEI-2005), which was based on the federal Dietary Guidelines for Americans; the 2010 Healthy Eating Index (HEI-2010), which reflects the most recent dietary guidelines and has an increased emphasis on quality; and the Alternate Healthy Eating Index-2010 (AHEI-2010), which is based on a different nutrition guide, the Healthy Eating Pyramid.
Women answered questions about their diet in the year leading up to a diagnosis (for patients) or to the time of an interview (for controls). They received scores based on numerous components of the three diets.
Qin said that among all African-American women in the study, those with the highest adherence to an AHEI-2010 diet were 34 percent less likely to be diagnosed with ovarian cancer than women with the lowest AHEI-2010 adherence.
Among postmenopausal women, the women with the highest quartile of HEI-2010 scores were 43 percent less likely to be diagnosed with ovarian cancer, and the women with the highest quartile AHEI-2010 scores were 51 percent less likely to be diagnosed with ovarian cancer than the women in the lowest quartile.
Qin said the benefits of HEI-2010 come from higher intake of total vegetables, greens, beans, seafood, and plant proteins, combined with lower intake of empty calories, such as those from solid fats, alcohol, and added sugars. Similarly, the benefits of AHEI-2010 derive from higher vegetable intake and lower intake of sugar-sweetened beverages and fruit juice.
The diets have many common elements, but AHEI-2010 has more specific recommendations for protein and fat sources, including nuts, legumes, and omega-3 fatty acids EPA and DHA. HEI-2010 uses an energy density approach, which recommends optimal intake of nutrients relative to a person's daily diet.
Qin said further research is necessary to determine whether all aspects of the healthier diets contributed to reduced risk, or whether specific nutrients conferred the benefits.
"As a high quality diet is likely to have benefits for many chronic conditions, it is probably a safe bet for better health in general," she said.
Qin said the main limitation of this study is that it required women to recall their diet up to one year before the study, which introduces the possibility of recall bias and inaccurate reporting.
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To interview Bo Qin, contact Julia Gunther at julia.gunther@aacr.org or 215-446-6896.
The study was funded by the National Cancer Institute. Qin and Bandera declare no conflicts of interest.
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Abstract: A67, PR05
Title: Dietary quality and ovarian cancer risk in African-American women
Authors: Bo Qin1, Patricia G. Moorman2, Anthony J. Alberg3, Jill S. Barnholtz-Sloan4, Melissa Bondy5, Michele L. Cote6, Ellen Funkhouser7, Edward S. Peters8, Ann G. Schwartz6, Paul Terry9, Joellen M. Schildkraut10, Elisa V. Bandera1. 1Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, 2Duke Cancer Institute, Durham, North Carolina, 3Medical University of South Carolina, Charleston, South Carolina, 4Case Western Reserve University School of Medicine, Cleveland, OH, 5Baylor College of Medicine, Houston, TX, 6Wayne State University School of Medicine, Detroit, MI, 7University of Alabama at Birmingham, Birmingham, AL, 8Louisiana State University Health Sciences Center School of Public Health, New Orleans, LA, 9University of Tennessee-Knoxville, Knoxville, TN, 10University of Virginia, Charlottesville, VA
Background: Ovarian cancer is the fifth leading cause of cancer death among women in the US. Considering the poor survival rates, identifying modifiable lifestyle factors including dietary interventions for ovarian cancer is needed. Compared to single foods or nutrients, examining dietary exposures as dietary patterns may allow us to accommodate the multidimensional aspects of diet and to better capture the role of diet in ovarian cancer carcinogenesis. Healthy Eating Index (HEI) is a measure of dietary quality to assess adherence to the Dietary Guidelines for Americans. Compared to HEI-2005 edition, HEI-2010 has an increased emphasis on dietary quality and reflects the most recent dietary guidelines. Alternate Healthy Eating Index-2010 (AHEI-2010), grounded in a different eating guide, the Healthy Eating Pyramid, was based on dietary predictors of chronic diseases. To our knowledge, this is the first study to evaluate the impact of dietary quality on ovarian cancer risk in African-American women.
Objective: We aimed to evaluate three index-based dietary patterns--HEI-2005, HEI-2010, AHEI-2010--in relation to ovarian cancer risk in African-American women.
Methods: Analyses were conducted among 415 cases of ovarian cancer and 629 controls using data from the African American Cancer Epidemiology Study (AACES). AACES is an ongoing population-based case-control study of ovarian cancer in African-American women in 11 sites in the US. Cases were identified through rapid case ascertainment and age- and site-matched controls were identified by random-digit-dialing. Information on risk factors related to ovarian cancer was collected by computer-assisted telephone interview. Dietary information 1 year before diagnosis (cases) or interview (controls) was obtained using a Block food frequency questionnaire (FFQ). AACES FFQ data were linked to the MyPyramid Equivalents Database 2.0 or based on published descriptions to generate equivalent intake for food groups under HEIs and AHEI-2010. Both HEIs includes 12 components, with total scores ranging from 0 to 100. AHEI-2010 includes 10 components with overall scores from 0 to 110. Higher scores indicate better adherence to a healthy diet. We used multivariate unconditional logistic regression models to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for potential socio-demographic and lifestyle risk factors.
Results: Only higher AHEI-2010 scores were associated with lower risk of ovarian cancer among all African-American women [OR comparing the highest quartile (Q4) vs. lowest (Q1) =0.66, 95% CI 0.45-0.98, p-trend =0.05]. The relationships between HEIs or AHEI and ovarian cancer risk were modified by menopausal status. Among post-menopausal women, we found lower risk of ovarian cancer with higher adherence of HEI-2010 (OR Q4 vs. Q1 =0.57, 95% CI 0.36-0.92, p-trend =0.03) and AHEI-2010 (OR Q4 vs. Q1 =0.49, 95% CI 0.31-0.78, p-trend =0.01). We observed no associations among pre-menopausal women. HEI-2005 was not associated with ovarian cancer risk among all or by menopausal status. Analyses evaluating individual score components with ovarian cancer risk suggested that in our sample of African-American women the benefits of HEI-2010 mainly come from higher intake of total vegetables, greens and beans, seafood and plant proteins and lower intake of empty calories (i.e., calories from solid fats, alcohol and added sugars). Consistently, the associations with AHEI-2010 were mainly driven by higher vegetable intake and lower intake of sugar-sweetened beverages and fruit juice.
Conclusion: Our findings suggest, for the first time, that a healthy diet is associated with lower risk of ovarian cancer in African Americans. Adherence to the current Dietary Guidelines for Americans may reduce ovarian cancer risk among post-menopausal African-American women.