NEW YORK (Reuters) -- Using hair dye may increase the risk of a type of cancer known as lymphoma, a European study shows.
"Our data suggest that personal use of hair coloring is associated with a small increase in lymphoma risk, particularly among women who started using hair coloring products before 1980," Dr. Silvia de Sanjose of the Catalan Institute of Oncology in Barcelona, Spain, and colleagues write in the July 1 issue of the American Journal of Epidemiology.
Past research has suggested a link between coloring one's hair and lymphoma risk, de Sanjose and her team note. They sought to investigate the association by analyzing results from a large study of lymphoma patients and matched healthy controls, including a total of 4,719 people from six European countries. About three-quarters of women reported using hair dye, while 7 percent of men did.
The researchers found an overall 19 percent increased risk of lymphoma among people who reported coloring their hair. The increased risk was 26 percent among those who used hair dye 12 or more times a year.
People who began coloring their hair before 1980 showed a 37 percent increased lymphoma risk, while those who had only dyed their hair before 1980, but not afterwards, showed a 62 percent increased risk.
Based on the findings, de Sanjose and her team calculate that roughly 10 percent of lymphomas in women could be due to the use of hair dye.
From 1978 to 1982, the researchers note, the ingredients of certain types of dyes were changed to eliminate some potentially cancer-causing agents. But it is not clear whether the newer dyes are risk-free. Clearly, more research is needed, they conclude.