Health Disparities

2002 and Earlier

EGRP grantees continue to improve the understanding of the basis of differences in cancer incidence and mortality. Some examples of their research and recent findings are described below:

• Researchers analyzed differences in breast cancer rates for Japanese-American, native Hawaiian, Latina, and non-Hispanic white women in Hawaii and Los Angeles, after taking into account established risk factors for the disease. The incidence rate for breast cancer for Japanese-American women equaled the rate for non-Hispanic white women, and the rate for native Hawaiians was 65% greater than the rate for non-Hispanic whites after adjusting for seven risk factors. The rate for migrant Latinas was 16% lower than that for non-Hispanic whites. Based on the distribution of risk factors, the researchers had expected breast cancer rates to be lower than they were for Japanese-American and native Hawaiian women. The finding for Japanese-American women is in sharp contrast to the historically low rates that have been observed in "traditional" Japanese women and in early Japanese migrants, and will need to be confirmed in other research. The researchers now are focusing on exploring reasons for the high rates among native Hawaiians.

  Pike MC, Kolonel LN, Henderson BE, Wilkens LR, Hankin JH, Feigelson HS, Wan PC, Stram DO, Nomura AM. Breast cancer in a multiethnic cohort in Hawaii and Los Angeles: Risk factor-adjusted Incidence in Japanese equals and in Hawaiians exceeds that in whites. Cancer Epidemiol Biomarkers Prev. 2002 Sep;11(9):795-800.
  

• A cohort of 64,524 African-American women was followed since 1995. The 704 women who reported breast cancer were compared to 1,408 age- and menopausal status-matched controls. The investigators found that strenuous physical activity (greater than or equal to 7 hours per week) at ages 21, 30, and 40 were associated with statistically significantly reduced breast cancer risks.

  Adams-Campbell LL, Rosenberg L, Rao RS, Palmer JR. Strenuous physical activity and breast cancer risk in African-American women. J Natl Med Assoc 2001;93:267-275.

• Interactions among genetic, race/ethnic, and other factors may jointly contribute to cancer risk. Polymorphisms in the gene encoding for microsomal epoxide hydroxylase (mEPHX), which are thought to affect metabolism of some tobacco-related carcinogens, were examined in Mexican-American and African-American lung cancer cases and Mexican-American and African-American controls in one recent study. Of two mEPHX polymorphisms studied, one of them (in exon 4) was associated with an increased risk of lung cancer in Mexican Americans only, especially younger Mexican Americans.

  Wu X, Gwyn K, Amos CI, Makan N, Hong WK, Spitz MR. The association of microsomal epoxide hydroxylase polymorphisms and lung cancer risk in African-Americans and Mexican-Americans. Carcinogenesis 2001;22:923-938.

• Women in Singapore experience much lower breast cancer risk than women in the United States do. Investigators at the University of Southern California hypothesized that these differences in risk might be a consequence of differences in the production of endogenous estrogens and in estrogen pathways. They compared healthy, non-estrogen-using, Singapore-Chinese women sampled from an ongoing cancer epidemiology study with U.S. women sampled from a large multiethnic cohort study. They found that urinary estrone, estradiol, and estriol reflect the differences in breast cancer risk between Chinese women in Singapore and U.S. women to a stronger degree than other estrogen metabolites.

  Ursin G, Wilson M, Henderson BE, Kolonel LN, Monroe K, Lee HP, Seow A, Yu MC, Stanczyk FZ, Gentzchein E. Do urinary estrogen metabolites reflect the differences in breast cancer risk between Singapore Chinese and United States African-American and white women? Cancer Res 2001;61:3326-3329.

• A total of 1,619 cases of prostate cancer in cancer registries in Hawaii, San Francisco, Los Angeles, British Columbia, and Ontario were compared to 1,618 male controls. Based on in-person interviews using a structured questionnaire, the investigators found that legumes and yellow-orange and cruciferous vegetables appeared to reduce the risk of prostate cancer. These findings were consistent among the African American, white, Japanese American, Canadian, Chinese American, or Canadian ethnic groups.

  Kolonel LN, Hankin JH, Whittemore AS, Wu AH, Gallagher RP, Wilkens LR, John EM, Howe GR, Dreon DM, West DW, Paffenbarger RS Jr. Vegetables, fruits, legumes and prostate cancer: A multi-ethnic case-control study. Cancer Epidemiol Biomarkers Prev 2000(8):795-804.