Rosenberg Lynn, Boggs Deborah A, Adams-Campbell Lucile L, Palmer Julie R
Slone Epidemiology Center at Boston University, Boston, Massachusetts 02215, USA.
Cancer Epidemiol Biomarkers Prev. 2007 May;16(5):1035-7. doi: 10.1158/1055-9965.EPI-06-0946.
Hair relaxers (straighteners) have been used by millions of African American women, often for many years. Relaxer ingredients can enter the body through scalp lesions and burns. Because manufacturers are not required to list all ingredients, these products may contain unknown harmful substances. We assessed hair relaxer use in relation to breast cancer incidence in the Black Women's Health Study, a nationwide follow-up study of African American women. Information on hair relaxer use was collected in 1997; 48,167 women were followed subsequently through 2003 for incident breast cancer. Incidence rate ratios of breast cancer were estimated with Cox regression. During 266,298 person-years of follow-up, 574 incident cases of breast cancer were ascertained. There were no increases in breast cancer risk associated with any categories of duration of hair relaxer use, frequency of use, age at first use, number of burns experienced during use, or type of relaxer used. The incidence rate ratio for use at least seven times a year for 20 or more years relative to use for less than a year was 0.98 (95% confidence interval, 0.78-1.39). These results suggest that hair relaxer use does not increase the incidence of breast cancer in African American women.
数百万非裔美国女性使用直发剂（拉直器），而且常常使用多年。直发剂成分可通过头皮损伤和灼伤进入人体。由于制造商无需列出所有成分，这些产品可能含有未知的有害物质。在针对非裔美国女性的全国性随访研究“黑人女性健康研究”中，我们评估了直发剂使用与乳腺癌发病率之间的关系。1997年收集了有关直发剂使用的信息；随后对48167名女性进行随访，直至2003年，以确定乳腺癌发病情况。用Cox回归估计乳腺癌的发病率比。在266298人年的随访期间，确诊了574例乳腺癌发病病例。使用直发剂的任何时长类别、使用频率、首次使用年龄、使用期间经历的灼伤次数或使用的直发剂类型，均未增加乳腺癌风险。相对于使用时间不足一年的情况，每年至少使用7次、持续20年或更长时间的发病率比为0.98（95%置信区间，0.78 - 1.39）。这些结果表明，使用直发剂不会增加非裔美国女性患乳腺癌的发病率。
