Phenoxy herbicides and non-Hodgkin's lymphoma in New Zealand: frequency and duration of herbicide use.

Determinants ofchronic bronchitis and lung dysfunction in Western Australian gold miners sIR-Gantt and Lincoln (1988;45:503) of the Philip Morris Management Corporation have wrongly inferred from our study of Western Australian gold miners (1987;44:810-8) that ". . . lung damaging conditions in mineral operations can cause individuals to be exceptionally likely to find satisfaction in smoking...." What they have ignored is the fact that in table 4 of our paper current smokers were shown to have more than a fourfold increase in obstructive chronic bronchitis after adjustment for mining experience. Thus the adverse effect of smoking cigarettes on lung function was not explained by smokers having worked in a more hazardous environment. Moreoever, the prevalence of smoking in the mineral industry should not be compared with the total male population of Australia without adjustment for differences in age structure and socioeconomic status.