title: Do urinary estrogen metabolites reflect the differences in breast cancer risk between Singapore Chinese and United States African-American and white women?
abstract: Breast cancer risk is substantially lower in Singapore than in women from the United STATES: Part of the risk discrepancy is probably explained by differences in the production of endogenous estrogens, but differences in the pathway by which estrogen is metabolized may also play a role. We undertook a study to determine whether the ratio of urinary 2-hydroxyestrone (2OHE(1)):16alpha-hydroxyestrone (16alpha-OHE(1)) was higher in Singapore Chinese than in a group of United States (predominantly African-American) women living in Los ANGELES: We also wanted to determine whether any difference in estrogen metabolite ratio between these two groups of women was greater than that in estrone (E(1)), estradiol (E(2)) and estriol (E(3)). The participants in this study were randomly selected healthy, non-estrogen using women participating in the Singapore Chinese Health Study (n = 67) or the Hawaii/Los Angeles Multiethnic Cohort Study (n = 58). After adjusting for age and age at menopause, mean urinary 2-OHE(1) was only 23% (P = 0.03) higher in Singapore Chinese than in United States women, and there were no statistically significant differences in 16alpha-OHE(1) levels or in the ratio of 2-OHE(1):16alpha-OHE(1) between the two groups. The adjusted mean 2-OHE(1):16alpha-OHE(1) ratio was 1.63 in Singapore Chinese and 1.48 in United States women (P = 0.41). In contrast, the adjusted mean values of E1, E2, and E3 were 162% (P < 0.0001), 152% (P < 0.0001), and 92% (P = 0.0009) higher, respectively, in United States women than in Singapore Chinese women. Our study suggests that urinary E1, E2, and E3 reflect the differences in breast cancer risk between Singapore Chinese and United States women to a stronger degree than the estrogen metabolites 2OHE(1) and 16alpha-OHE(1) or the ratio of 2OHE(1):16alpha-OHE(1.)
authors: Department of Preventive Medicine, University of Southern California/Norris Comprehensive Cancer Center, 1441 Eastlake Avenue, Suite 4407, Los Angeles, CA 90089, USA. gursin@hsc.usc.edu
authors: G
authors: G
authors: Ursin
authors: M
authors: M
authors: Wilson
authors: B E
authors: BE
authors: Henderson
authors: L N
authors: LN
authors: Kolonel
authors: K
authors: K
authors: Monroe
authors: H P
authors: HP
authors: Lee
authors: A
authors: A
authors: Seow
authors: M C
authors: MC
authors: Yu
authors: F Z
authors: FZ
authors: Stanczyk
authors: E
authors: E
authors: Gentzschein
mesh_terms: D000368:Aged; D044383:Black People; D001943:Breast Neoplasms / Q000652:urine*; D002681:China; D015331:Cohort Studies; D004958:Estradiol / Q000652:urine; D004964:Estriol / Q000652:urine; D004967:Estrogens / Q000652:urine*; D004970:Estrone / Q000652:urine; D005006:Ethnicity; D005260:Female; D006801:Humans; D008875:Middle Aged; D012307:Risk Factors; D044465:White People; D001741:Black or African American
chemical_list: D004967:Estrogens; D004970:Estrone; D004958:Estradiol; D004964:Estriol