Overview
Ovarian cancer is the deadliest gynecologic cancer and the eighth-most common cancer among both white and African-American women and the fifth most common cause of cancer death in the United States. Although African-American women have lower incidence rates than white women (10.1 cases per 100,000 women compared to 14.1 cases per 100,000 women), they have lower 5-year survival, probably due to an advanced stage at diagnosis. And, there has been relatively little research in this population of women. It turns out that the risk factors for ovarian cancer are similar in both groups, such as a lower risk with increased parity and oral contraceptive use.
Risk Factors
African-American women have a tendency for a greater number of pregnancies, a higher rate of tubal ligation, a lower prevalence of endometriosis, and less use of menopausal hormones, all of which are linked to a lower incidence of ovarian cancer. They also tend to have an earlier age at menarche, are more likely to be obese, and are less likely to breastfeed, which could contribute to a higher risk of ovarian cancer.
This study conducted by Moorman et al., in 2009 aimed to determine the risk factors for developing invasive ovarian cancer in the two populations by conducting nurse interviews on affected and case-control unaffected women. In African American women, there were 143 cases, while whites had 943 cases. The information obtained was a 90-minute questionnaire, blood samples, and measurement of height, weight, and waist and hip circumferences. Questions asked were those often associated with ovarian cancer risk. These included:
· Family history of cancer;
· Menstrual history such as age at menarche and cycle length;
· Age for each pregnancy, pregnancy duration and outcome,
· Duration of breastfeeding;
· Type, timing, and duration of hormone and contraceptive use;
· Lifestyle characteristics such as smoking history, alcohol consumption during the five years before the interview, and level of physical activity.
Results of Study
The results revealed that in age-adjusted analyses, the major reproductive factors that have been associated with an increased rate of ovarian cancer among white women were similar to the risk among African-American women. Those at a reduced rate of ovarian cancer were women who were parous, were older for their last pregnancy, had used oral contraceptives for one year or more, or had had a tubal ligation.
In this study, the prevalences for Africa American compared to whites were 29% and 18% for age at menarche less than 12 years, 6% and 10% for nulligravidity, 51% and 33% for tubal ligation, and 51% and 26% for BMI ≥30
However, there was not a positive effect on the number of pregnancies in African-American women, and a history of infertility or endometriosis was associated with a slightly increased risk for African American women, but it did not reach statistical significance like it did in white women.
A family history of breast or ovarian cancer in a first-degree relative was associated with increased risk in both racial groups, but with a stronger association among African Americans. Unlike for African American women, later age at menarche and history of ever breastfeeding were associated with reduced risk in white women. Taller height and BMI>35 may be associated with increased risk among African-American women but not among white women. “The overall lower rate of ovarian cancer in African American women may be due to the higher rates of tubal ligations,” according to Patricia Moorman, the principal investigator in the study.
Because there is a higher prevalence of obesity among African-American women at a young age, they opine that African-American women may be at higher risk for ovarian cancer diagnosed at a younger age. This is consistent with the higher proportion of premenopausal ovarian cancer cases in African Americans as compared to whites (34% vs. 26%) and the younger mean age at diagnosis (54.8 years vs. 57.4 years)
Conclusion
The results of this study must be viewed with caution due to the small number of African American Women studied. A more comprehensive study was funded by the National Cancer Institute of the National Institute of Health and conducted by Theresa Dolecek, PhD, and found that those who had healthier diets lived longer. Yellow and cruciferous vegetables like broccoli, cauliflower, and kale were most beneficial. Those who ate red meat, processed or cured meat four or more times a week had a three times higher death rate than those who avoided red meats. Likewise, African American women who had a calcium-rich and low-lactose diet had a reduced risk for developing ovarian cancer. Longer sun exposure in the summer was also protective of the disease, which correlates with higher vitamin D levels, according to research published in the British Journal of Cancer. Future studies need to focus on risk factors, both lifestyle and genetic, along with prognostic indicators that point to types of treatment and access to care specific to African American women.
References
1. Moorman, P. G., Palmieri, R. T., Akushevich, L., Berchuck, A., & Schildkraut, J. M. (2009). Ovarian cancer risk factors in African-American and white women. American journal of epidemiology, 170(5), 598–606. https://doi.org/10.1093/aje/kwp176
2. Ries LA, Melbert D, Krapcho M, et al., editors. SEER Cancer Statistics Review, 1975–2005. Bethesda, MD: National Cancer Institute; 2008. ( http://seer.cancer.gov/csr/1975_2005/). (Accessed February 1, 2009) [Google Scholar]
3. Jemal A, Siegel R, Ward E, et al. Cancer statistics, 2008. CA Cancer J Clin. 2008;58(2):71–96. [PubMed] [Google Scholar]
4. Bernstein L, Teal CR, Joslyn S, et al. Ethnicity-related variation in breast cancer risk factors. Cancer. 2003;97(suppl 1):222–229. [PubMed] [Google Scholar]
5. Godecker AL, Thomson E, Bumpass LL. Union status, marital history and female contraceptive sterilization in the United States. Fam Plann Perspect. 2001;33(1):35–41. [PubMed] [Google Scholar]
6. Martin JA, Hamilton BE, Sutton PD, et al. Births: final data for 2005. Natl Vital Stat Rep. 2007;56(6):1–103. [PubMed] [Google Scholar]
7. Missmer SA, Hankinson SE, Spiegelman D, et al. Incidence of laparoscopically confirmed endometriosis by demographic, anthropometric, and lifestyle factors. Am J Epidemiol. 2004;160(8):784–796. [PubMed] [Google Scholar]
8. Marsh JV, Brett KM, Miller LC. Racial differences in hormone replacement therapy prescriptions. Obstet Gynecol. 1999;93(6):999–1003. [PubMed] [Google Scholar]
9. McDowell MA, Brody DJ, Hughes JP. Has age at menarche changed? Results from the National Health and Nutrition Examination Survey (NHANES) 1999–2004. J Adolesc Health. 2007;40(3):227–231. [PubMed] [Google Scholar]
10. Ogden CL, Carroll MD, Curtin LR, et al. Prevalence of overweight and obesity in the United States, 1999–2004. JAMA. 2006;295(13):1549–1555.