To estimate the incidence of Wernicke's encephalopathy (WE) and Korsakoffs psychosis (KP) before and after the introduction of thiamin enrichment of bread in Australia.

Inpatient records were examined in 17 major public general hospitals in greater Sydney for the 4 years 1993–96 (inclusive) with the International Classification of Diseases (ICD) 9 diagnoses 265.1 (WE), 291.1 and 294.0 (KP). Relevant clinical data were recorded on a specially designed form so that cases could be classified as confirmed or probable WE, confirmed or probable KP, confirmed or probable Wernicke–Korsakoff syndrome (WE + KP) or not WE or KP. The average number of cases of WE + KP was 38 acute (new) cases and 69 total (acute+chronic) cases per annum for all the hospitals combined.

This study used the same methods as our earlier retrospective examination of Wernicke–Korsakoff cases in essentially the same hospitals for 1978–93. Records for 1993 were thus pulled twice and, while individual cases (using hospital index number) did not always coincide, the total numbers for 1993 were 69 and 70.

For the 5 years after 1991 the number of acute cases of WE and KP in Sydney hospitals was 61% of the number for the 5 years before 1991 (P<0.01). There is, however, no continuing downward trend.

These results are consistent with a 40% reduction of the incidence of acute WE and KP since bread has been enriched with thiamin. The disease complex has, however, not been eliminated. To achieve this, further public health action would be needed, such as addition of thiamin to beer.