Dyeing your hair appears to increase your risk of developing a type of cancer called lymphoma, Reuters reports of a study conducted at the Catalan Institute of Oncology in Barcelona, Spain that confirms similar findings from earlier research studies.

The study: Led by Dr. Silvia de Sanjose, the team analyzed results from another study of 4,719 people from six European countries, half of whom had lymphoma and half of whom were matched healthy controls. In this study, 75 percent of the women reported using hair dye, while 7 percent of the men did.

The results: Among those who used hair dye, there was a 19 percent increased risk of lymphoma, but that risk jumped to 26 percent among those who used it 12 or more times during the year. Those who started dyeing their hair prior to 1980 had a 37 percent increased risk of developing lymphoma, while those who only dyed their hair before 1980 had a 62 percent increased risk. Based on this, the team concluded that about 10 percent of lymphoma cases in women are caused by using hair dye.

Why 1980? It was between 1978 and 1982 that formulas were changed for certain types of hair dyes that contained potentially cancer-causing agents. Still, de Sanjose notes that it is not certain new dyes are totally risk-free. "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," de Sanjose wrote in the American Journal of Epidemiology. She emphasized that more research is needed.