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.
Few data exist on the extent to which the differences in breast cancer risk between "racial-ethnic" groups in the United States (US) are "explained" by differences in their distribution of risk factors. We have determined this for African-American (AA), native Hawaiian (NH), Japanese-American (JA), Latina-US-born (L-US), Latina-non-US-born (L-NUS), and white (W) women using prospective incidence data on 88,712 postmenopausal women recruited in 1993-1996. We identified 1,757 incident breast cancer cases through 1999 among these women (1,116 cases after excluding women with a simple hysterectomy or missing risk factor data). Data were available on seven "known" risk factors: ages at menarche and first birth; parity; age at and type of menopause; weight; hormone replacement therapy use; and alcohol consumption. The relative risks (RRs) of breast cancer (with the RR in Ws set to 1.0) for the groups were as follows: W = 1.0; AA = 0.78; NH = 1.33; JA = 0.99; L-US = 0.77; and L-NUS = 0.60. After adjustment for the risk factors, the RRs were as follows: W = 1.0; AA = 0.98; NH = 1.65; JA = 1.11; L-US = 0.95; and L-NUSB = 0.84. The slightly greater risk of the JAs compared with the Ws is in sharp contrast to the very low breast cancer rates that were observed in "traditional" Japanese women and in early Japanese migrants. The adjusted RR of NHs is 65% greater than that of Ws, and that of migrant Latinas is 16% lower than that of Ws. Elucidating the causes of the high rates in NHs is now a major focus of our efforts.
Pike
Malcolm C
MC
Department of Preventive Medicine, University of Southern California/Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA. mcpike@usc.edu
Kolonel
Laurence N
LN
Henderson
Brian E
BE
Wilkens
Lynne R
LR
Hankin
Jean H
JH
Feigelson
Heather Spencer
HS
Wan
Peggy C
PC
Stram
Daniel O
DO
Nomura
Abraham M Y
AM
D000368:Aged; D001213:Asian / Q000706:statistics & numerical data*; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000208:ethnology*; D015331:Cohort Studies; D005260:Female; D006254:Hawaii / Q000453:epidemiology; D006630:Hispanic or Latino / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D015141:Los Angeles / Q000453:epidemiology; D008875:Middle Aged; D017698:Postmenopause; D012307:Risk Factors; D044465:White People / Q000706:statistics & numerical data*