Hair dye increases the risk of lymphoma (a type of cancer)

Posted: July 2006

Beautiful artificial hair colour comes at a cost. A number of previous studies showed linkage between hair dye and lymphoma, bladder cancer, arthritis and damage to unborn children.

A recent European study published on July 1, 2006 in the American Journal of Epidemiology supported the view that using hair dye may increase the risk of lymphoma, a type of cancer. This study was conducted by researchers in the Catalan Institute of Oncology in Barcelona, Spain.

In studying a total of 4,719 people from 6 European countries, researchers found that there was an overall 19% increased risk of lymphoma among those who coloured their hair. For those who dyed their hair 12 times or more a year, the increased risk of lymphoma was 26%.

Based on the findings, it was estimated that roughly 10% of lymphomas in women could be due to the use of hair dye.

The Type of Hair Dye Counts

The ingredients of hair dyes before 1980 were more potent in causing lymphoma. It was found in the above study that people who started dyeing their hair before 1980 had a 37% increase in lymphoma risk. For those who had only dyed their hair before 1980, but not afterwards, showed a 62% increased risk.

From 1978 to 1982, the ingredients of certain hair dyes were changed to eliminate some potentially cancer-causing agents. However, more research is required to determine whether the newer dyes are risk-free.

Hair Dyes with Darker Shades are more harmful

All permanent hair colours use the same basic ingredients, but darker shades have about 100 times more chemicals than the lightest blonde shade. Hence, the darker hair dyes are potentially more carcinogenic than the lighter ones.

Chemicals in hair dye can damage the body's genetic materials

Scientists are particularly worried about two chemical ingredients in hair dye, namely para-phenylenediamine and tetrahydro-6-nitroquinoxaline. These chemicals have been shown to damage the body's genetic materials, and to cause cancer in animals.

In May 2006, a woman in Hong Kong who dyed her hair regularly once every 3 months in the past 15 years was diagnosed with lymphoma. The doctors suspected the carcinogenic chemicals in hair dyes entered her body through the hair follicles and accumulated in the lymph nodes. After prolonged exposure to carcinogens, the cells in the lymph node developed abnormal cancerous growth.

It is advisable for consumers to avoid using hair dyes. If it is unavoidable, it is better to use the dyes for a shorter duration, use lighter shades, or reduce skin contact with the dye.