31 March 2010
Dyeing your hair and smoking linked to liver disease
Hair dye and smoking both increase the risk of a type of liver disease, suggests research published in the journal Gut.
Researchers in Manchester and Newcastle studied around 5,000 people aged between 36 and 90. The study was population-based and case-controlled. This is where a group of people with a certain disease is compared with a control group of people who don't have the disease. The two groups of people are matched to try to get similar people in each group.
The aim of this study was to look at the effects of environmental factors such as smoking, drinking and use of hair products to find out if they were linked to an increased risk of primary biliary cirrhosis (PBC), a type of liver disease.
The researchers looked at 318 people who had been diagnosed with liver disease between 1997 and 2003, and 2,258 members of the United Kingdom PBC Foundation, a national support group for people with the condition. Finally, 2,438 people randomly selected from the electoral roll, and matched for age and sex, were used as a control group.
All three groups were asked questions about their medical history, lifestyle and potential environmental and genetic risk factors associated with PBC.
The researchers reported that compared to the control group, people with PBC were more likely to have smoked, and to have started smoking before their diagnosis. The researchers also found women with PBC used hair dye slightly more frequently than women without the condition.
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Dr Annabel Bentley, Assistant Medical Director, Bupa |
There is not enough evidence from this single study to suggest people stop using hair dye. 
But, the women weren't asked how often they dyed their hair, and it is unclear which part of the hair dye may be responsible for the effect, the researchers said. However, previous studies have shown a link between cirrhosis and a chemical found in cosmetics called octynoic acid, which is used in hair dye and nail polish.
Previous bouts of urinary infection, psoriasis and shingles increased the risk more than hair dye as did autoimmune diseases such as rheumatoid arthritis, thyroid and coeliac diseases.
The researchers concluded that smoking, hair dye use and family history of autoimmune disease as well as urinary infections are associated with the increased risk of liver disease. They suggest that obstetric cholestasis, a certain liver complication in pregnancy, may also be a risk factor but this requires further study.
Alison Rogers, Chief Executive of the British Liver Trust, however, cautions against reading too much into this research and said: "The biggest risk factor for PBC for example is not dyeing your hair but being female - women outnumber men with the disease 10 to one."
Commenting on the research, Dr Annabel Bentley, Assistant Medical Director for Bupa, said: "This research is a case-control study which cannot prove cause and effect. The links to liver disease in this study were greater for other autoimmune conditions and smoking than hair dye. Not enough is known about whether hair dye is a significant factor in the development of primary biliary cirrhosis. There is not enough evidence from this single study to suggest people stop using hair dye."
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Read the study
Prince MI, Ducker SJ, James O FW. Case-control studies of risk factors for primary biliary cirrhosis in two United Kingdom populations. Gut 2010; 59:508-12. doi: 10.1136/gut.2009.184218
