I hear there's new research on the hair color/cancer issue. Has a connection been established?

The latest word on this continuing concern comes from the International Agency for Research on Cancer (IARC), which has concluded that working regularly with hair dyes in hair salons¹ and barbershops probably increases the risk of cancer and that long term employment in these establishments is "probably carcinogenic to humans."

However, the IARC, a World Health Organization panel, reported that there is not enough evidence to conclude that occasional personal use of hair coloring raises the risk of cancer.

This new report, published in the April, 2008, issue of Lancet Oncology, is the first scientific word on the subject since 2005, when Spanish researchers reported that their review of 79 studies from 11 countries yielded no strong evidence of a link between hair dye and cancer risk. The only connection the Spanish team observed was the possibility of a slight increase in the risks of leukemia and multiple myeloma, but they concluded that the causal effect was too weak to be a major concern.

Earlier, researchers at Yale University found that long-term use of dark hair dye by women who began coloring their hair before 1980 may increase the risk of non-Hodgkin's lymphoma. No such risk was seen among women who began dyeing their hair after 1980. Here, the difference may be due to the elimination² of coal-tar-derived ingredients used in the older products that are known carcinogens. The Yale study was published in the Jan. 15, 2004, issue of the American Journal of Epidemiology.

In general, I discourage use of hair dyes containing artificial coloring agents, which to my mind are as suspect in cosmetic³ products as they are in food. Hair dyes applied⁴ to the head are absorbed through the scalp, where there's a very rich blood supply that may carry them throughout the body. I'm sure that the new IARC report won't be the last word on this subject. I'll keep you posted on developments.

我听说了关于染发致癌的新研究。这两者间有关系吗？

人们对于染发致癌持续关注，最新的说法来源于国际癌症研究机构，机构推断在理发沙龙和理发店工作、定期接触染发剂，将会增加得癌症的几率，在这些地方长期受雇会对人体产生致癌物质。

然而，国家癌症研究机构，作为世界卫生组织的代表，报道说并没有足够的证据说明偶然使用染发剂会有致癌风险。

此最新报道出版于08年4月的《柳叶刀—肿瘤学》。这是自2005年来，西班牙研究者重新研究了11个国家的79项调查并得出没有足够的证据支持染发剂和致癌风险的关系之后，第一次有科学上的报道。

早些年的时候，耶鲁大学的研究者发现，在1980年前开始使用染发剂的女性长期使用黑色染发剂，也许会增加得非霍金奇淋巴瘤的几率。在1980年后染发的 女性中没有看到如此症状。也许原因归于旧时产品中的衍生的煤焦油元素，它是一种致癌物质。耶鲁大学的研究发表于2004年1月15日的《美国流行病学杂 志》。

总体来说，我不赞成使用带有人工色素染剂的染发剂，对于我来说，对化妆用品的不可信就像对食物中一样。用于头部的染发 剂被头皮吸收，头皮处有非常丰富的血液供给组织，也许将会把他们传送到全身上下。我确信国家癌症研究机构的最新报道不会是对这一问题的最终说法。我会为你 们提供这方面的最新消息。