Geographical distribution of variant Creutzfeldt-Jakob disease in Great Britain, 1994-2000

Background Geographical variation in the distribution of variant Creutzfefd t-Jakob disease (vCJD) might indicate the transmission route of the infecti ous agent to man. We investigated whether regional incidences of vCJD were correlated with regional dietary data. Methods The National CJD Surveillance Unit prospectively identified 84 peop le with vCJD up to Nov 10, 2000, in Great Britain. Their lifetime residenti al histories were obtained by interviews with a close relative. Cumulative incidences of vCJD by standard region were calculated. Grid references for places of residence in 1991 were identified and evidence of geographical cl usters were sought. Data on diet in the 1980s were analysed for regional co rrelations with vCJD incidence. The socioeconomic status of the places of r esidence of people with vCJD was compared with that of the general populati on. Findings vCJD incidence was higher in the north of Great Britain than the s outh. The rate ratio (north vs south) was 1.94 (95% CI 1.27-2.98). The mean Carstairs' deprivation score for areas of residence of people with vCJD wa s -0.09 (-0.73 to 0.55), which is close to the national average of zero. Re gional rates of vCJD were correlated with consumption of other meat or meat products as classified and recorded by the Household Food Consumption and Expenditure Survey (r=0.72), but not with data from the Dietary and Nutriti onal Survey of British Adults. Five people with vCJD in Leicestershire form ed a cluster (p=0.004). Interpretation Regional differences in vCJD incidence are unlikely to be du e to ascertainment bias. We had difficulty determining whether regional var iations in diet might cause these differences, since the results of dietary analyses were inconsistent.