Margaret A.WinkerMD, Deputy EditorIndividualAuthorPhil B.FontanarosaMD, Interim CoeditorIndividualAuthor
To the Editor: Two studies in JAMA1,2 purport to demonstrate that "lifestyle"
and "structured interventions" are equally successful in increasing physical
activity and improving cardiovascular risk factor profiles. One article, for
example, concluded that ". . . both the lifestyle and the structured interventions
produced significant and comparable beneficial changes in physical activity,
cardiorespiratory fitness, blood pressure, and percentage of body fat at 24
months compared with baseline measures."1
This conclusion gains apparent strength from the fact that the studies in
question are randomized controlled trials. However, in neither study is there
a true control group and the conclusion is based on similar before and after
changes in groups randomized to lifestyle or structured interventions.
Smith GD, Ebrahim S. Lifestyle and Structured Interventions to Increase Physical Activity. JAMA. 1999;282(16):1515-1517. doi:10-1001/pubs.JAMA-ISSN-0098-7484-282-16-jbk1027