Abstract
A single risk factor can increase the risk of developing multiple diseases, but most risk communication research has been conducted in the context of a single disease. We explored which combination of three recommended risk communication strategies is most effective in simultaneously conveying risk estimates of four diseases associated with physical inactivity: colon cancer, stroke, diabetes, and heart disease. Participants (N = 1161, 50% no college experience, 50% racial/ethnic minority) were shown hypothetical risk estimates for each of the four diseases. All four diseases were placed at varying heights on 1 of 12 vertical bar charts (i.e., "risk ladders") to indicate their respective probabilities. The risk ladders varied in a 2 (risk reduction information: present/absent) × 2 (numerical format: words/words and numbers) × 3 (social comparison information: none/somewhat higher than average/much higher than average) full factorial design. Participants were randomly assigned to view one of the risk ladders and then completed a questionnaire assessing message comprehension, message acceptance, physical activity-related risk and efficacy beliefs, and physical activity intentions. Higher message acceptance was found among (1) people who received risk reduction information versus those who did not (p = .01), and (2) people who did not receive social comparison information versus those told that they were at higher than average risk (p = .03). Further, absolute cognitive perceived risk of developing "any of the diseases shown in the picture" was higher among people who did not receive social comparison information (p = .03). No other main effects and only very few interactions with demographic variables were found. Combining recommended risk communication strategies did not improve or impair key cognitive or affective precursors of health behavior change. It might not be necessary to provide people with extensive information when communicating risk estimates of multiple diseases.