An informational stair climbing intervention with greater effects in overweight pedestrians.

Previous interventions have successfully increased levels of stair climbing in public-access settings (e.g. malls). This study used robust methods to establish the magnitude of intervention effects among a specific target group-the overweight. Ascending stair/escalator users (N = 20 807) were observed in a mall. A 2-week baseline was followed by a 5-week intervention in which message banners, promoting stair climbing, were attached to the stair risers. Standardized silhouettes were used to code individuals as normal/overweight. Logistic regression analyses were conducted with stair/escalator choice as the outcome variable and weight status entered as a moderator alongside condition, gender, ethnicity and 'pedestrian traffic volume'. Overall, the intervention significantly increased the rate of stair climbing [odds ratio (OR) = 1.28, 95% confidence intervals (CI) = 1.08-1.53], with the effects sustained over 5 weeks. There were differential effects between weight categories, with greater increases in overweight (OR = 1.95, CI = 1.34-2.83) versus normal weight individuals (OR = 1.29, CI = 1.09-1.53). In conclusion, message prompts produced larger effects among overweight individuals, who could benefit most from stair climbing. The public health value of these interventions may, therefore, be greater than realized. The heightened effects among the overweight were likely due to the salience of the current message, which linked stair climbing with the target of weight control.