[100 years of lead poisoning studies from a reading of articles published in La Medicina del Lavoro].
In preparing this paper we considered the articles published in La Medicina del Lavoro from 1901, its first year of publication. This scientific journal was founded in Milan, when an animated debate arose in Italy on the necessity of treating and, above all, preventing occupational diseases. In the same city, the "Clinica del Lavoro" (i.e. Institute of Occupational Medicine) was inaugurated in 1910. Its founder, Professor Luigi Devoto, had to overcome numerous obstacles caused by the hostility of the Rector of the University of Pavia--the future Nobel prize winner Camillo Golgi--and the clinicians of the main hospital of Milan, founded by Francesco Sforza in the XV century. From reading a century of articles which appeared in La Medicina del Lavoro, it is clear that for occupational physicians lead is an exemplary topic by which to evaluate the evolution of research in the field of occupational diseases. The numerous pathological features of lead poisoning, the successive therapeutic responses of physicians, and the gradual development of preventive techniques constitute a paradigm that has subsequently been applied to all other fields of industrial toxicology. Reading the papers of 100 years gives a clear picture of the evolution of clinical syndromes over the decades. The pathological picture of lead poisoning gradually became less serious and progressively changed into aspecific, subclinical manifestations. The categories of workers in which lead poisoning had a high incidence changed over the years: painters, printers and munition makers had the highest incidence in the first three decades of this century; afterwards, those engaged in lead smelting, alloy production, painters, and in the last few decades those employed in battery, ceramic and PVC production. Prevention consisted mainly of early diagnosis of lead poisoning and instruction in proper hygiene measures. Later, in 1929, insurance of occupational diseases was made compulsory in Italy, and among the few risk factors covered by law were lead and its compounds. This law was a great advance not only in the diagnostic and insurance fields but also for prevention. Two aspects of occupational lead poisoning are particularly instructive: treatment on the one hand and the use of laboratory analysis on the other. In treatment, the initial approach was mainly empirical and physicians insisted on evacuation of the bowel. Laboratory analysis started in the 20's with analysis of erythrocytes with basophilic stippling and continued with the study of urinary porphyrins. This was followed by the determination of lead in blood and urine. These tests were used initially as diagnostic tools, and only since the 60's they have been used for biological monitoring of workers for preventive purposes. The identification of indicators of dose, of critical/subcritical effect, and of critical organ started with studies on lead poisoning. Since then, following this model, biological monitoring has been applied to numerous other metals, solvents, and pesticides. The evaluation of the Italian scientific literature on lead over one hundred years in La Medicina del Lavoro has been a very exciting experience. It suggests that knowledge of the evaluation of lead poisoning and lead exposure should be taught to medical students and young physicians, thereby stimulating them to put into practice the maxim that was engraved on the foundation stone of the Clinica del Lavoro: in aliis vivimus, movemur et sumus.