Risk factors for sporadic Creutzfeldt-Jakob disease

Objective: Although surgical transmission of Creutzfeldt-Jakob disease (CJD) has been demonstrated, these iatrogenic cases account for only a small proportion of all CJD cases. The majority are sporadic CJD (sCJD) cases of unknown cause. This study investigated whether some cases classified as sCJD might have an unrecognized iatrogenic basis through surgical or other medical procedures. Methods: This study compared medical risk factors from 431 sCJD cases referred 1998 to 2006 with 454 population control subjects. Possible geographic and temporal links between neurological and gynecological operations in 857 sCJD cases referred from 1990 to 2006 were investigated. Results: A reported history of ever having undergone surgery was associated with increased risk for sCJD (odds ratio, 2.0; 95% confidence interval, 1.3-2.1; p = 0.003). Increased risk was not associated with surgical categories chosen a priori but was confined to the residual category other surgery, in which the increase in risk appeared most marked for three subcategories: skin stitches, nose/throat operations, and removal of growths/cysts/moles. No convincing evidence was found of links (same hospital, within 2 years) between cases undergoing neurosurgery or gynecological surgery. Interpretation: It is unlikely that a high proportion of UK sCJD cases are the result of transmission during surgery, but we cannot exclude the possibility that such transmission occurs occasionally. A study based on accurate surgical histories obtained from medical records is required to determine whether the increased risk associated with reported surgical history reflects a causal association or recall bias