ABU DHABI // Emirati women are almost twice as likely as men to develop leukaemia, and synthetic forms of henna dye could be the cause, scientists believe. A study by UAE University published in the journal Leukaemia and Lymphoma found the rate of acute myeloid leukaemia - an often-fatal cancer of the blood and bone marrow - was 93 per cent higher among Emirati women than men. Emirati women were also 63 per cent more likely to be affected than expatriate women.
The study looked at 263 cases of acute myeloid leukaemia (AML) and acute lymphoblastic leukaemia (ALL) over a seven-year period from January 2000 to December 2006. It found that the rate of AML among UAE nationals was 78 per cent higher than in expatriates. The rate of ALL was 25 per cent higher in Emiratis. Emirati women were also almost twice as likely as Emirati men to develop acute myeloid leukaemia.
Risk factors linked to leukaemia include age, exposure to radiation, smoking and genetic disorders. However, it remains very rare. Even among Emirati women - the group most at risk - the disease affects fewer than three in 100,000. Dr Inaam Hassan, an associate professor at the UAE University in Al Ain, said chemicals in henna dye, which is used to decorate the body, as well as a lack of sunlight could be behind the increased incidence.
"I could not understand the results because men and women live in the same environment; they eat the same foods and breathe the same air," she said. "The only difference was the use of henna." Decorative henna is used on many occasions, including a child's first day at school, weddings or Eid celebrations, she said. Henna is a small plant and the dye extracted from it is traditionally used to decorate skin, nails, hair and fabrics. Many modern henna dyes, however, use synthetic chemicals such as benzene to produce a deeper colour, and it is these chemicals experts are worried about.
Benzene is also found in petrol and tobacco smoke. It is known to be carcinogenic and can affect the liver, lungs, heart and kidneys. The US Food and Drug Administration does not allow henna plant dye to be used on the skin. "The henna used here is often made with benzene, [which] is a well documented factor causing this specific type of leukaemia," Dr Hassan said. "Women here use henna on all occasions, and children also use it. They don't only put it on their hands, they put it on their whole arms."
Abu Dhabi Municipality routinely inspects beauty salons and sends henna samples to the health authority for testing. Khalifa al Romaithi, of the municipality's public health department, said pre-mixed henna was often found to contain harmful chemicals such as benzene. "If we find pre-mixed henna, we will test it," he said. "Salons should be using the pure henna powder and mixing it with a little water. When we find henna stored in the freezer, it is suspicious and we will test it.
"They might have added something they shouldn't have." Salons found to be mixing henna powder with chemicals face fines of up to Dh10,000 (US$2,700). Referring to a previous findings, Dr Hassan said another factor could be a lack of vitamin D. Because the body needs sunlight to make the vitamin, "traditional, conservative outdoors clothing" can mean some people here - especially women - are deficient.
Dr Wesam Kadhum, a dermatologist at the Gulf Medical University Hospital in Ajman, said chemicals regularly applied to the skin could have a dangerous cumulative effect, depending on the size of the molecule. "If the molecule is small enough it can enter the body through the skin," he said. "Chemicals such as benzene, lead and mercury can all have a cumulative effect if they are used many times. "They affect the neurosystem and the blood, but these trace elements are not easily measured."
He said the effect of benzene in henna warranted further study, especially in light of the UAE University findings. As well as the internal dangers, chemicals in henna could also harm the skin, according to Dr Hussein Abdel Dayem, chief dermatologist at Mafraq Hospital in Abu Dhabi. Benzene, in particular, could cause blisters and sores if used in large quantities. "If it is bad enough, someone may even need to see a doctor," he said. "This is not uncommon when the henna is mixed with chemicals."
Josy Zaraa, the general manager of Eva Beauty Salon in the capital, said many young women now opted for temporary tattooing instead of traditional henna paste. "They are more educated," she said. "Many salons mix it with chemicals to darken the colour, but younger women know this." Despite the increasing popularity of temporary tattoos, she said, henna as a cultural tradition would remain. "It will always be used, but it needs to be used properly."
munderwood@thenational.ae