Epidemiology of primary central nervous system neoplasms. II. Case-control study.

Choi, N. W . (Dept. Social and Preventive Medicine, Univ. of Manitoba, Winnipeg 3, Manitoba, Canada), L M. Schuman and W . H. Gullen. Epidemiology of primary central nervous system neoplasms. II. Case-control study. Amer. J. Epid., 1970, 97: 467-485.—This retrospective study was designed to elucidate selected epidemiologic variables possibly related to central nervous system (CNS) neoplasms. One hundred and fifty seven pairs of cases and matched controls, from four hospitals in the Minneapolis-St. Paul Metropolitan area, were analyzed. The following results and interpretation are presented: 1) A familial aggregation of "brain tumors" was observed among relatives of the study subjects. No specific association was found among the groupings of tumor types and ABO blood type and Rh positivity. On the basis of the observed familial aggregation, the possible role of a genetic factor in the genesis of central nervous system neoplasms cannot -' be rejected. 2) The possible importance of the extrinsic factors in the genesis of the neoplasms, especially for gliomas of young children, was hypothecated on the grounds that considerably higher proportions with abnormal delivery history, i.e., forceps delivery and cesarean section, etc., among the study subjects were reported. A significant association between the occurrence of gliomas and a history of previous abortion occurring to the mothers of the study subjects was also noted. 3) A relationship between primary CNS neoplasms and past medical history with regard to various illnesses and brain trauma was not, for the most part, substantiated in this study, except for a significant association of the neoplasms with certain symptoms noted prior to diagnosis of such neoplasms, e.g., between gliomas and "convulsions", "trouble with the central nervous system", "eye troubles" and "enlarged glands", etc. The possibility that such clinical phenomena in some cases were the results of tumor development was not ruled out. 4) Analyses of history of cigarette and alcohol consumption resulted in a negative association with the neoplasms, while no association between the neoplasms and pipe or cigar smoking was noted. According to the evidence described above, it appears to the authors that both genetic and environmental factors may share a role in the genesis of certain CNS neoplasms, especially gliomas.