EPIDEMIOLOGY OF PRIMARY CENTRAL NERVOUS SYSTEM NEOPLASMS

Abstract

Choi, N. W. (Dept. Soda I and Preventive Medicine, Univ. of Manitoba, Winnipeg 3, Manitoba, Canada), L M. Schuman and W. H. Gullen. Epidemiology of primary central nervous system neoplasms. I. Mortality from primary nervous system neoplasms in Minnesota. Amer. J. Epid., 1970, 91: 238–259.—Little light has been shed on the tenability of any of the theories of the etiology or pathogenesis of central nervous system neoplasms. To obtain data on the pattern of occurrence in the general population in Minnesota and possibly the roles of host and environmental factors, records of all patients with primary central nervous system neoplasms who died in the five-year period 1958–1962, inclusive, were compiled and a total of 760 cases were found. The epidemiologic variables were compared with the distribution of these variables in the general population. Bimodality of age-sex specific mortality rates, differential sex selectivity by types of the tumors, and significantly higher mortality among farm residents and foreign-bom persons (especially younger age groups) were among the significant findings. These findings may imply multiple causalities or factors differing by tumor type, age, sex, etc. No geographic gradient of the rates (by county) or differential rates by occupation were noted. The high mortality of farm residents is coherent with the theory that a possible relationship exists between toxoplasmosis and certain brain tumors (Schuman, L M., Choi, N. W., and Gullen, W. H. Relationship of central nervous system neoplasms to Toxoplasma gondii infection. Amer. J. Publ. Hlth., 1967, 57: 848.) The higher mortality among the foreign-born population may imply that the origin of brain tumors among younger age groups resides in congenital factors, either innate or via the fetal environment, or via the environment in early childhood, both peculiar to the place of birth. In view of the fact that several countries of birth, including Norway, Germany, Canada and Finland, were among those foreign countries from which immigrants had excess proportions of brain tumor deaths, more extensive observations on the foreign-bom population from such countries and in such countries may be worthwhile. Implication of the present epidemiologic findings is discussed in conjunction with the prevailing theories of etiology or pathogenesis of the neoplasms.