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This investigation is, to our knowledge, the first population-based case-control study of prenatal, perinatal, and postnatal risk factors for generalized tonic-clonic seizures (GTCS). The clinical diagnosis of GTCS was confirmed through the independent review of the complete medical history of potential cases by three neurologists. All subjects with onset of GTCS before age 30 who were residents of Rochester, Minnesota at time of diagnosis between 1935 and 1979, and who were born in this community, were included (N = 53). Two controls were matched to each patient, and for both patients and controls, the unique records-linkage system for residents of Rochester was used to obtain information about possible risk factors. A history of convulsions in the mother, febrile seizures, and head trauma were significantly more common in cases than in controls. However, factors previously suggested such as: advanced age of the mother, previous miscarriages, gestational toxemia or eclampsia, bleeding during the index pregnancy, low birth weight, asphyxia, or postmaturity were not confirmed. Based on the present and previous studies, we suggest that different types of seizures have different risk factors and should, therefore, be investigated separately.

A case-control study was conducted on 64 cases of “probable Alzheimer's disease” with late onset of illness (after age 70 years) and 64 controls matched by age (± 3 years), race, and sex. Information was obtained on birth order, lifetime medical and surgical history, personal characteristics, exposure to toxins and animals, and a family history of various illnesses. None of the variables studied, including family history of dementia, reached statistical significance. An antecedent history of head trauma with loss of consciousness, though not statistically significant, was more frequently found in cases than in controls.

The age-specific incidence pattern for tumors of the brain and cranial meninges in Connecticut over a 30-year period shows an early peak followed by a taller and sharper peak with a maximum in the 55-65 year age group. This overall curve reflects the pattern shown for glioblastoma, the tumor accounting for the majority of the histologically confirmed cases. The reported rates are probably underestimates of the actual rates. The various histologic types of brain tumors reveal sufficiently distinct epidemiologic patterns to be considered as separate diseases.