Unintentional falls in older adults: a methodological historical review

PubMed lists over 6,000 references (700 reviews) on unintentional falls in older adults. This article traces key methodological milestones in the application of epidemiologic methods since the earliest publications in the late 1940s. Within the context of advances in case definition, sampling, measurement, research design, and statistical analysis, the article reviews estimates of frequency of occurrence, risk factor associations, morbidity and mortality consequences, demonstration of the multiple risk factor theory of falls using fall prevention interventions, and the challenges of fall risk prediction models. Methodological explanations are provided for observed heterogeneities, and the case is presented for moving beyond undifferentiated lists of risk factors by focusing on balance and gait as the factors through which the mechanistic effects of distal risk factors can be understood. Moreover, the case is made to advance our statistical analyses by looking at interactions among intrinsic risk factors and between intrinsic, extrinsic, and environmental factors.