about current health issues. Participants who were living in long-term-care institutions were given a clinical examination. Those living in the community were interviewed in their homes and then screened for dementia. A community interview was held to discuss general health issues, disability, and the presence of chronic ailments. Screening tests for cognitive impairment were administered, including the Modified Mini-Mental State Examination. A person who screened positive for impairment was asked to participate in a clinical examination; independent diagnoses were also made by a physician and a neuropsychologist.
The clinical examination included neuropsychologic tests and medical assessment to permit a preliminary diagnosis of dementia. The diagnoses were the basis of the incidence and prevalence rates and were used in followup studies to identify risk factors. Followup studies included the same diagnostic criteria; cases were reassessed to be diagnosed according to new criteria based on the DSM-IV.
In CSHA-1, 10,263 participants were identified; 9,008 lived in the community, and 1,255 lived in institutions. Participants who were included were interviewed about health issues and limitations in performing basic daily-life activities as assessed by the Older Americans’ Resources and Services Activities of Daily Living Scale (Lindsay et al., 2002).
A case–control study was conducted to assess risk factors associated with Alzheimer disease or other dementias (CSHA, 1994). The participants were given a questionnaire that included questions about family and medical history, behavior, occupational and environmental exposures, and lifestyle. To avoid recall bias, questionnaires for participants with dementia were given to persons who knew them well. The study included 258 patients with probable Alzheimer disease, 129 with vascular dementia, and 535 normal controls. All participants who did not have cognitive impairment during this first phase were asked to complete a risk-factor questionnaire; these included 6,628 participants without cognitive impairment. A case–control study based on data from CSHA-1 (CSHA, 1994) found that age, family history of dementia, educational level, arthritis, and use of nonsteroidal anti-inflammatory drugs were significantly related to Alzheimer disease.
In 1996–1997, the subjects who had agreed to participate in CSHA-2 were interviewed to determine changes in health status during the prior 5 years and underwent a process similar to that in CSHA-1. During CSHA-2, investigators conducted a nested case–control study of 194 participants who had recently diagnosed Alzheimer disease and 3,894 controls. For vascular dementia, 105 newly diagnosed cases were compared with controls (Lindsay et al., 2002). The authors found that increasing age, fewer years of education, and the apolipoprotein e4 (APOE 4) allele were significantly associated with increased risk of Alzheimer disease. However, they found no statistically significant association between Alzheimer disease and family history of dementia, history of depression, sex, estrogen-replacement therapy, head trauma, antiperspirant or antacid use, smoking, high blood pressure, heart disease, or stroke.
The Traumatic Brain Injury Model Systems (TBIMS) program was established in 1987 by the National Institute on Disability and Rehabilitation Research of the US Department of Education. It consists of 16 nationwide centers, which provide acute hospital and rehabilitation care. Inclusion criteria for the TBIMS database, from which numerous prospective and retrospective conditional studies have been derived, are as follows: moderate to severe TBI