BIRTHPLACE AND YIELD OF NIPPLE ASPIRATE FLUID IN CHINESE WOMEN

The different rates of breast cancer found between Chinese women in As ia compared with Chinese-born women in the United States suggest that dietary and environmental factors may be of etiological significance. We evaluated the proportion of 480 premenopausal Chinese women who yie lded nipple aspirate fluid (NAF) by birthplace in Asia versus the Unit ed States and by reproductive and other risk factors. Birthplace was u sed as a surrogate for presumed differences in exposures during gestat ion, childhood, and adolescence that might influence yield of NAF in p remenopausal women. In United States-born Chinese women compared with Asia-born Chinese women, the proportion yielding NAF was 44 of 95 (46. 3%) versus 120 of 385 (31.2%), respectively. The relative risk of yiel d of NAF in United States-born women compared with Asia-born women was odds ratio = 2.37 (95% confidence interval, 1.26-4.47). Independent p ositive associations of NAF yield were also found with history of pari ty and breast feeding, cerumen phenotype, and a negative association w ith ever use of oral contraceptives. These findings support the hypoth esis that early environmental exposures may have long-lasting physiolo gical effects discernible in the breast glands of adult women.