青春期染发、直发、烫发与乳腺癌风险
美发护发产品可能包含多种激素活性物质和致癌化合物，而青春期可能是乳腺组织暴露于化学物质的易感性增强时期。不过，青春期染发、直发、烫发对成年期乳腺癌发病风险的影响尚不明确。
2020年11月30日，国际抗癌联盟《国际癌症杂志》在线发表美国国家环境卫生科学研究所、北卡罗来纳大学、国家少数种族健康与健康差异研究所的姐妹研究分析报告，对青春期美发护发产品与成年期乳腺癌发病风险之间的关联进行了调查。
该大样本前瞻研究于2003～2009年从美国和波多黎各自由邦入组自己无乳腺癌史、其姐妹有乳腺癌史的年龄35～74岁女性50884例，其中47522例入组时完成关于10～13岁时染发剂、直发剂或柔顺剂和烫发的调查问卷，并随访至2018年9月23日。通过多因素比例风险回归模型，对入组年龄、初潮年龄、是否绝经、家庭教育、家庭收入、种族等其他影响因素进行校正后，推算美发护发产品不同用量的乳腺浸润癌或乳腺导管癌发病风险比和95%置信区间。
结果，平均10年随访期间，共发生3380例乳腺浸润癌或乳腺导管癌。
10～13岁时经常用直发剂与从不用直发剂的女性相比：
乳腺癌发病风险相似（风险比：1.14，95%置信区间：0.90～1.45，P=0.4）
绝经前乳腺癌发病风险高111%（风险比：2.11，95%置信区间：1.26～3.55，P=0.004）
绝经后乳腺癌发病风险相似（风险比：0.99，95%置信区间：0.76～1.30，P=0.7）
10～13岁时经常烫发与从不烫发的女性相比：
乳腺癌发病风险相似（风险比：1.14，95%置信区间：0.94～1.38，P=0.2）
绝经前乳腺癌发病风险高55%（风险比：1.55，95%置信区间：0.96～2.53，P=0.7）
绝经后乳腺癌发病风险相似（风险比：1.09，95%置信区间：0.89～1.35，P=0.1）
10～13岁时用永久染发剂（仅占3%）与从不用永久染发剂的女性相比：
乳腺癌发病风险相似（风险比：0.97，95%置信区间：0.78～1.20）
绝经前乳腺癌发病风险相似（风险比：1.00，95%置信区间：0.60～1.67）
绝经后乳腺癌发病风险相似（风险比：0.97，95%置信区间：0.77～1.23）
10～13岁时用永久染发剂与从不用永久染发剂的黑人女性相比：
乳腺癌发病风险高77%（风险比：1.77，95%置信区间：1.01～3.11，P=0.06）
虽然不同种族的烫发比例（非西班牙裔白人37%，黑人9%）和直发比例（非西班牙裔白人3%，黑人75%）显著不同，但是乳腺癌发病风险相似。
因此，该研究结果表明，青春期使用美发护发产品，尤其烫发和直发剂，可能增加成年期绝经前乳腺癌发病风险，且与种族无关。青春期使用永久染发剂对成年期乳腺癌发病风险的影响主要见于黑人女性。
相关链接
Int J Cancer. 2020 Nov 30. Online ahead of print.
Adolescent use of hair dyes, straighteners and perms in relation to breast cancer risk.
White AJ, Gregoire AM, Taylor KW, Eberle C, Gaston S, O'Brien KM, Jackson CL, Sandler DP.
National Institute of Environmental Health Sciences, Durham, North Carolina; University of North Carolina at Chapel Hill, North Carolina; National Institute on Minority Health and Health Disparities, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA.
Hair products can contain hormonally active and carcinogenic compounds. Adolescence may be a period of enhanced susceptibility of the breast tissue to exposure to chemicals. We therefore evaluated associations between adolescent hair product use and breast cancer risk. Sister Study participants (ages 35-74 years) who had completed enrollment questionnaires (2003-2009) on use of hair dyes, straighteners/relaxers, and perms at ages 10-13 years (N = 47522) were included. Cox proportional hazards regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for associations between hair products and incident breast cancer (invasive cancer or ductal carcinoma in situ), with consideration of heterogeneity by menopausal status and race/ethnicity. Over an average of 10 years of follow-up, 3380 cases were diagnosed. Frequent use of straighteners and perms was associated with a higher risk of premenopausal (HR = 2.11, 95% CI 1.26-3.55 and HR = 1.55, 95%CI: 0.96-2.53, respectively) but not postmenopausal breast cancer (HR = 0.99, 95% CI: 0.76-1.30 and HR = 1.09, 95% CI: 0.89-1.35, respectively). Permanent hair dye use during adolescence was uncommon (<3%) and not associated with breast cancer overall (HR = 0.97, 95% CI: 0.78-1.20), though any permanent dye use was associated with a higher risk among Black women (HR = 1.77, 95% CI: 1.01-3.11). Although frequency of use of perms (37% non-Hispanic white vs 9% Black) and straighteners (3% non-Hispanic white vs 75% Black) varied by race/ethnicity, associations with breast cancer did not. Use of hair products, specifically perms and straighteners, during adolescence may be associated with a higher risk of premenopausal breast cancer.
KEYWORDS: breast cancer; early life; hair dye; hair products; straighteners
PMID: 33252833
DOI: 10.1002/ijc.33413