In the Kungsholmen (Sweden) Project,23 1301 subjects aged 75 years and older were followed up for an average of 3 years. Cognitive functions were assessed using the Mini-Mental State Examination and other psychometric tests, and Diagnostic and Statistical Manual of Mental Disorders, Third Edition,25 criteria when needed for establishing dementia (more information about these methods is available from the authors). At the end of the follow-up period, 987 subjects were still alive. In the subpopulation with an SBP higher than 160 mm Hg, a DBP higher than 95 mm Hg, or both (n = 458), 122 received diuretic therapy. Compared with untreated patients, the subjects thus treated showed an adjusted relative risk for dementia of 0.6 (95% confidence interval, 0.3-1.2). This trend was tentatively interpreted by the authors as a potential benefit from diuretic treatment. But they fully recognized the limitations of the results, in that information of drug use was only available at baseline, the duration of treatment being unknown. Moreover, the group using antihypertensive medication in this cohort differed inherently from the untreated group due to the presence of heart disease and stroke in the latter, another example of confounding by indication. Therefore, these authors, like the previous ones, admitted the need for clinical trials.