10 April 1998
Research fails to find link between beef and CJD
The largest study to date of the risks of contracting the human form of mad cow disease has found no evidence of links with eating beef, veal, lamb, cheese or dairy products of from blood transfusions.
The study of risk factors involved in Creutzfeldt-Jakob disease (CJD) from the European Collaborative Study Group has found a tendency for there to be higher levels of dementia, not caused by CJD, in the families of cases they investigated. The cases studied, which included a large group of British patients, looked at “classical” CJD.
Dr Cornelia Van Duijn, of the Erasmus University Medical School, Rotterdam, who led the study, said that while a small number of cases of new variant CJD were included, the numbers were too small for them to be considered separately. As it is new variant CJD that has been most closely associated with eating beef, the researchers say their findings must be treated cautiously until more information is available.
The researchers found a link between CJD and eating raw meat, brain and pork, with using fertilisers containing cow hoof and horn and exposure to leather including wearing it. But workers in the leather industry showed no increased risk of CJD. The research is reported in The Lancet.
Dr Duijn said they did not understand the leather findings. The higher risk among pork eaters was also a puzzle since there is no increase of spongiform encephalopathy, the animal brain disease, in pigs.
She said: “We have looked at classical CJD in a narrow time frame. But we have to wait a lot longer to get a real picture.” Even significant links could reflect a “statistical fluke” rather than a genuine cause and effect.
The researchers think that sufferers may have an inherited susceptibility to a number of conditions that include Alzheimers disease and prion protein disorders. Prions are the agents found in cases of CJD.