Topical chloramphenicol and the risk of acute leukaemia in adults

Purpose - To investigate the possible role of topical chloramphenicol in th e development of adult acute leukaemia. Methods - The design of the study was a population-based age- and sex-match ed case-control study, which collected cases of adult acute leukaemia betwe en 1991 and 1996. Caucasian cases (807) and 1593 Caucasian controls were in terviewed in person using a highly structured questionnaire. General practi tioner medical records were abstracted for previous topical chloramphenicol use. Results - 797 cases and 1570 controls were included in the analysis. No ass ociation was observed for topical chloramphenicol use and acute leukaemia ( adjusted odds ratio, I-year lag period (OR) 0.91 95% confidence interval (C I) 0.70-1.17). Similar results were observed when the analysis was repeated by diagnostic subgroup and sex. For all the data, a small, non-significant increased risk was observed (OR = 1.21, 95% CI 0.65-2.25) if chloramphenic ol had been prescribed three, or more times, but there was no statistically significant dose-response relationship (chi(2) = 1.40, two-sided p = 0.24) . Conclusions - The results, based on a robust study design, show no evidence of an increased risk of developing adult acute leukaemia after topical chl oramphenicol use. Copyright (C) 2000 John Wiley & Sons, Ltd.