Individual subject random assignment is the preferred means of evaluating behavioral lifestyle modification

Abstract

Of the three most important approaches to evaluating lifestyle and health outcomes--observational studies, individual subject random assignment clinical trials, and community random assignment clinical trials--individual subject random assignment clinical trials provide the most useful information and the most certain inferences. Observational studies are limited by the collection of information on association of lifestyle instead of change in lifestyle with health outcomes, as well as by individual lifestyle selection that may be associated with particular outcomes. Community randomized trials may be the best way to decide such public health policy issues as whether or not to add fluoride to a water supply or to use a community-wide anti-smoking program. The limited amount of individual-specific data collected in community randomized trials, difficulties in accounting for missing data, and problems in data analysis because people move into or out of communities that are under study limit the value of community randomized trials for advising individuals whether or not to embark on a lifestyle modification program. Clinical trials of pharmacologic agents have successfully addressed challenges to individual subject random assignment clinical trials of lifestyle modification, such as long duration of study, access to study intervention(s) by individuals not assigned them, and cost.