Epidemiology of aplastic anaemia in the state of Sabah, Malaysia.

Aplastic anaemia is a rare disease which is more prevalent in the Far East. In Malaysia, it appears to be unusually common in the state of Sabah. A retrospective analysis of all cases of aplastic anaemia diagnosed between January 1993 and March 1996 was undertaken. The criteria of the International Aplastic Anaemia and Agranulocytosis Study (IAAAS) was used. In this 39 month period, 31 cases were confirmed by marrow trephine biopsy to be aplastic anaemia. The male-to-female ratio was 3.4. Median age of diagnosis was 23 years. There were 24 patients (77%) who were from the Kadazan-Dusun ethnic group, which forms 18% of the population of Sabah. The incidence of aplastic anaemia in Sabah appears to be higher than that reported elsewhere in the Far East, at 4.8 per million population per year. Peak incidence is in the elderly group at 8.6 per million followed by a second peak in young people aged 15 to 24 (7.9 per million). The aplastic anaemia to total acute leukaemia ratio is 0.37. The marked male preponderance and apparent susceptibility of the Kadazan-Dusun people are also notable. A further prospective study to address the true incidence of aplastic anaemia and possible aetiologic factors accounting for these observations is necessary.