ArticlesSurgical treatment and risk of sporadic Creutzfeldt-Jakob disease: a case-control study
Introduction
By contrast with iatrogenic and familial cases of Creutzfeldt-Jakob disease (CJD), the aetiology of the most common form, sporadic CJD, which constitutes 85–90% of all cases,1, 2 is unknown. One hypothesis is that sporadic disease is caused by a rare (one in a million) spontaneous somatic mutation within the cerebral neuronal pool of the prion protein (PrP).3 An alternative is low-level contamination events.4 The excess of homozygosity at codon 129 in iatrogenic disease5 has also been found in sporadic CJD, and may increase the chance of normal PrP (PrPC) converting to the abnormal, disease-associated isoform (PrPSC) when the normal and abnormal conformers interact, as could occur after a contamination event.
Previous case-control studies have investigated possible causes or risk factors for sporadic CJD, without identifying any consistent or major influences.7, 8, 9, 10, 11, 12, 13, 14 In our case-control study of risk factors for sporadic CJD, we used the Australian National Creutzfeldt-Jakob Disease Registry to ascertain cases. Controls were recruited from the general community by random telephone survey, unlike most previous studies that used hospital-based controls.9, 10, 11, 12, 13, 14
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Cases
The Australian National Creutzfeldt-Jakob Disease Registry 15 collected cases retrospectively to Jan 1, 1970, and prospectively from Oct 1, 1993. 241 patients with sporadic CJD (122 men, mean age 63·1 years, 119 women, mean age 66·6 years; combined age range 25–84 years) represented all Australian cases of sporadic CJD that occurred up to Oct 31, 1997. The diagnostic subclassifications of this cohort were 151 definite (neuropathologically confirmed) and 90 probable (clinically likely) cases of
Results
784 controls completed the telephone interview. 12 387 telephone calls were made, 2577 (21%) of which were number unobtainable, engaged, or no reply, and in 22 (0·2%) calls an appointment was made to ring back. In 1308 (11%) of the calls, permission for the interview was refused, and in 7349 (60%), the relevant age, sex, and urban or rural residence quota was full. Of the 1131 calls in which interviews began, 347 calls were halted—the respondent did not want to continue in 63 (6%), there were
Discussion
In this case-control study, we found a range of surgical treatments were associated with an increased risk of sporadic CJD. Two previous case-control studies, also with community controls, found the risk of CJD was associated with hospital-related therapy,8, 9 but this significance was lost when the data were pooled as part of a meta-analysis.13 The absence of this finding in a third study12 may reflect methodological differences, since the controls were selected only from hospital populations
References (19)
- et al.
Genetic predisposition to iatrogenic Creutzfeldt-Jakob disease
Lancet
(1991) - et al.
Case-control study of risk factors of Creutzfeldt-Jakob disease in Europe during 1993–95
Lancet
(1998) - et al.
“Friendly fire” in medicine: hormones, homografts, and Creutzfeldt-Jakob disease
Lancet
(1992) - et al.
Transmission of Creutzfeldt-Jakob disease by blood transfusion
Lancet
(1993) - et al.
Creutzfeldt-Jakob disease: patterns of worldwide occurrence and the significance of familial and sporadic clustering
Ann Neurol
(1979) - et al.
Human spongiform encephalopathy: the National Institutes of Health series of 300 cases of experimentally transmitted disease
Ann Neurol
(1994) Prion diseases and the BSE crisis
Science
(1997)- et al.
Transmissions to mice indicate that ‘new variant’ CJD is caused by the BSE agent
Nature
(1997) - et al.
Creutzfeldt-Jakob disease: a case-control study
Am J Epidemiol
(1973)