Studies in Occupational Morbidity (1)

The influence of occupation on health has been recognized throughout the centuries. More than two hundred years ago Ramazzini, the father of industrial medicine, advised that in the examination of a patient it was of the utmost importance to ascertain the nature of his work. It is clear from his descriptions that he made himself intimately acquainted with the working conditions obtaining in a wide variety of employments. To-day it is recog nized that an efficient industrial medical officer, in order to complete his contributions to the prevention and treatment of sickness and injury and to factory hygiene, should, ideally, acquaint himself with the precise nature of every occupation upon which members of his working population may be engaged, and as far as possible with the previous health and occupational histories of all employees brought under his observation. Although an increasing interest has been taken since Ramazzini's time in the possible correlations between occupation and sickness, accurate infor mation remained for a long time fragmentary. It was not until Farr initiated in this country the collection of figures bearing on occupational mor tality that any degree of precision in our knowledge was attained. His researches in this field, like his other investigations, have been regarded as classic studies, and the policy which he originally formulated governed the compilation of data up to 1920. In the Occupational Mortality Supplement of the Registrar-General for 1921-3, an attempt was made to collect the statistics on an occupational rather than, as previously, a purely industrial basis. The differentiation is important because under the industrial allocation the mortality of some trades was heavily diluted by the inclusion of figures for other workers industrially related but not exposed to the same occupational risk. This was particularly true of workers engaged in occupations involving risk of silicosis. This alteration was, then, the first improvement in our more precise knowledge of occupational influence. In the succeeding Supplement, based on the statistics for the years 1930-2, a still more important addition was made, for not only was the mortality of the male workers recorded, but also that of the wives of workers engaged in corresponding occu pations. This information enabled a comparison to be made between direct and indirect occupational influence, because, if the excess mortality in an occupation was observable amongst males only, then the implication would be that the cause was purely occupational. If, on the other hand, both men and women experienced abnormal rates of mortality, then the high incidence could more legitimately be ascribed to the effects of a bad social environment. This idea of comparing the mor tality of men and wives was not a new conception. Hay, who was interested in the relative influence of ' seed and soil ' in tuberculosis, analysed similar statistics in Aberdeen many years ago. Neverthe less, the Registrar-General has considerably en riched our knowledge of medical statistics by his publication of the national data. From the infor mation which he has compiled in this extremely valuable report, we learn that the seven occupations with the highest standardized mortality ratios (registered deaths expressed as a percentage of the calculated or expected number of deaths in the particular occupation) amongst males aged 20-65 were: