PRELIMINARY ASSESSMENT OF THE MEDICAL AND FUNCTIONAL FACTORS ASSOCIATED WITH VEHICLE CRASHES BY OLDER ADULTS

OBJECTIVES: To examine associations between medical and functional var iables and at-fault far crashes in a cohort of older drivers. DESIGN: A case-control study. SETTING: A tertiary care medical center. PARTICI PANTS: Older drivers (ages 55-90 years) residing in Jefferson County, Alabama (n = 174). Cases were drivers who had at least one at-fault cr ash in the previous 6 years; controls were crash-free during the same period. MEASUREMENTS: Self-reported medical conditions, reported and o bserved functional measures, and urinary drug screens. The occurrence of one or more at-fault car crashes in the 6 years preceding the 1991 assessment date represented the outcome measure. RESULTS: Ninety-nine older drivers experienced between one and seven at-fault vehicle crash es during the period 1985 through 1991, whereas 75 drivers did not. Lo gistic regression models indicated that the following variables were i ndependently associated with crash involvement: A 40% or greater reduc tion in the useful field of view (OR = 6.1; 95% CI, 2.9 to 12.7; P < 0 .001), black race (OR = 6.6; 95% CI, 1.7 to 26.2; P = .007), a history of falling in the previous 2 years (OR = 2.6; CI, 1.1 to 6.1; P = .02 5), and not taking a beta-blocking drug (OR = 4.3; CI, 1.2 to 15.0; P = .023). CONCLUSIONS: Functional assessments, such as a comprehensive test of visual processing, a falls history, and a review of current me dications may be of greater relevance than specific medical conditions in the identification of older at risk drivers. If prospective studie s determine that falling and crashing share risk factors, a unified ap proach to the prevention of these mobility disorders could result. The finding of an independent association of black race with at-fault cra shing is in need of further clarification because of the low represent ation of black drivers in this sample.