PapersMortality from dementia in occupations at risk of exposure to bovine spongiform encephalopathy: analysis of death registrationsCommentary: Uncertainty over length of incubation tempers optimism
BMJ 1999; 318 doi: https://doi.org/10.1136/bmj.318.7190.1044 (Published 17 April 1999) Cite this as: BMJ 1999;318:1044Mortality from dementia in occupations at risk of exposure to bovine spongiform encephalopathy: analysis of death registrations
- Aylin Paul, senior clinical lecturer (p.aylin@ic.ac.uk)a,
- Bunting Julia, researcherb,
- Stavola Bianca De, senior lecturerc,
- Coleman MichelP, deputy chief medical statisticianb
- aDepartment of Epidemiology and Public Health,Imperial College of Medicine at St Mary's, London W2 1PG
- bHealth and Demography, Office for National Statistics,London SW1V 2QQ,
- cDepartment of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT
- Correspondence to: Dr Aylin
Since the early 1980s close contact with animals or animal products infected with bovine spongiform encephalopathy has posed a putative risk of infection with Creutzfeldt-Jakob disease.Several groups with potentially high exposure have already been identified.1
To study whether transmissible spongiform encephalopathy has had any effect on people working in animal husbandry and slaughter, we used national mortality records to examine patterns of mortality from Creutzfeldt-Jakob disease and other dementias during 1979-80 and1982-96.
Subjects, methods, and results
We studied people who died aged 20-74 years during 1979-1996 in England and Wales and for whom the occupational information recorded at death included butcher and abattoir worker,farmer and farm worker, or veterinarian. Women were selected on the basis of their own occupation, if recorded, or on the occupation of their spouse.
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The causes of death selected for study were Creutzfeldt-Jakob disease(ICD-9 046.1) and a wide range of dementias, including those most likely to be misdiagnosed as Creutzfeldt-Jakob disease.2 It was not possible to separate deaths from new variant disease. There were in any case too few deaths from new variant Creutzfeldt-Jakob disease within the study period (13 deaths during 1994-633) to include them as a separate category.
We calculated the age standardised proportional mortality ratio for …