The French case–control study found a large positive association between HL and occupational exposure to urea herbicides (OR 10.8, 95 % CI 2.4–48.1) [6]. However, our study did not find any significant association with this group of herbicides. This may be because the individual urea herbicides reported by the few participants who used these were different in the two studies. However, the especially small number of individuals (5 cases and 4 controls) exposed to urea herbicides in the French case– control study increases the possibility of chance findings.