Can Inexpensive Signs Encourage the Use of Stairs? Results from a Community Intervention

The American Heart Association recently added a sedentary lifestyle to its list of modifiable risk factors [1]. Reports suggest that only 22% of the U.S. adult population are active enough to derive health benefits from their physical activity and that one in four Americans are completely sedentary [2]. This finding may parallel the sharp increase in the prevalence of overweight persons over the past 12 years, from 25% in the National Health and Nutrition Examination Survey (NHANES II) in 1976-1980 to 33% in phase I of NHANES III in 1988-1991 [3]. The Centers for Disease Control and Prevention and the American College of Sports Medicine recently revised their recommendation regarding exercise to suggest that all Americans should accumulate 30 minutes or more of moderate-intensity physical activity on most or all days of the week [4]. Inactive people who increase their levels of physical activity are less likely to die of all causes and of cardiovascular disease than those who remain sedentary [5, 6]. Walking and taking the stairs instead of escalators or elevators may be two easy ways for seemingly healthy sedentary adults to become more moderately active [7-10]. In 1980, Brownell and associates [11] examined the effects of placing a sign that encouraged stair use for health benefits at the base of an escalator that was adjacent to a flight of stairs in a mall, train station, and bus terminal in Philadelphia. They reported that the sign resulted in statistically significant increases in stair use among 45 694 commuters. They also noted that overweight persons did not use the stairs as often as leaner persons before or after the sign was erected. Blamey and colleagues [12] recently examined the effects of encouraging stair use for health benefits in a Scottish train station and also found that a low-cost sign could result in statistically significantly increases in stair use by adults. We examined the trends among shoppers of different ages, ethnicities, sexes, and body weights in a shopping mall in which escalators and stairs were adjacent. We also observed the differential effects of adding signs at the base of the escalator that promoted stair use for health benefits or weight control. Methods Participants We observed 17 901 adult patrons of a mall located in a Baltimore suburb while they used the stairs or escalators. Because of the potential for artifactual influence on the decision process, persons carrying items larger than a briefcase were excluded. We also excluded persons carrying a baby or child and those judged to be younger than 18 years of age. Participants were unaware that they were part of a study investigating physical activity patterns. Design This observational study involved an initial baseline phase and two subsequent intervention phases that incorporated motivational signs displayed at the base of the escalator and stairs. Each of the three phases lasted 1 month. During the baseline phase, the frequency of stair use compared with use of the adjacent escalator was recorded. During the first interventional phase (health benefits), a 22 28 sign was placed on an easel beside the escalator and stairs. The sign featured a caricature of a heart at the top of a flight of stairs and the statement, Your heart needs exercise, use the stairs. During the second interventional phase (weight control), a similar-sized sign was placed on an easel. The sign featured a caricature of a woman at the top of a flight of stairs; she had a thin waistline and was wearing pants with a waist that was too large. The caption on the sign read, Improve your waistline, use the stairs. Setting In this suburban Baltimore mall, participants could use the escalator or the stairs to get to the second floor. A stairway was adjacent to ascending and descending escalators. The stairway consisted of 10 stairs, a 6-foot landing, and 10 more stairs. Observations were made during June, July, and August between 10:30 a.m. and 9:00 p.m. on all days of the week. Procedures Observations were made by one of the authors. A previous physical activity study [11] used many observers to ensure valid observation of all persons. However, the volume of mall traffic was never so heavy that more than one observer was needed to code the characteristics and choice of each person. Before the study began, the observer and the senior author spent one full day in the mall classifying shoppers by age and weight status to be sure that observations were as accurate as possible. The observer sat in an inconspicuous spot at the foot of the steps that allowed for clear observation. Frequency of stair use was recorded in the same way during each of the three phases. Each person's sex and ethnicity (black, white, or other) was recorded. In addition, persons were judged to be 40 years of age or older or younger than 40 years of age. Finally, the observer noted whether the person appeared overweight. Statistical Analysis The change in proportions of persons using the stairs from the baseline to the intervention phases of the study was analyzed by using the chi-square test and by computing 95% CIs around the differences in proportions between the comparison groups. The same procedure was used to examine intergroup differences (normal weight or overweight) within a given phase of the study. We also computed the number needed to treat (NNT), the number of shoppers who needed to be exposed to the sign to get one shopper to use the stairs, as 1/RD, where RD is expressed as the difference in proportions between the two comparison groups. Results are presented as the proportion of persons who opted to use the stairs rather than the escalator; 95% CIs are presented with associated P values and the NNT. Data were analyzed by using the SPSS for Windows (version 8.0) statistical package [13]. Results A total of 17 901 observations were made. Overall, the use of stairs at baseline was 4.8%. During the intervention period when the health benefits sign was displayed, stair use increased significantly to 6.9% (difference, 2.1 percentage points [CI, 1.3 to 2.8 percentage points]; NNT, 48). Compared with the baseline value, stair use also increased significantly to 7.2% when the weight-control sign was displayed (difference, 2.4 percentage points [CI, 1.5 to 3.2 percentage points]; NNT, 42). Stair use did not differ between the health benefits (6.9%) and the weight-control (7.2%) signs (difference, 0.3 percentage points [CI, 0.5 to 1.2 percentage points]; NNT, 333). Sex Table 1 and Table 3 shows the percentage of persons who used the stairs during the study's three phases as a function of age, sex, race, and body weight. Table 2 shows the change in stair use with the two signs and the change from the health benefits sign to the weight-control sign. A similar pattern emerged among men and women: Compared with baseline levels of stair use, both the health benefits sign and the weight-control sign increased stair use from 4.9% to 7.2% and 7.4%, respectively, among women and from 4.8% to 6.4% and 7.0%, respectively, among men). No sex-related differences were found when no sign or either type of sign was present. Table 1. Stair Use before and during Placement of Two Different Motivational Signs Table 3. Table 1 Continued Table 2. Changes in Stair Use among Groups of Shoppers in Response to Signs Promoting Stair Use Age At baseline, 4.6% of persons judged to be younger than 40 years of age used the stairs. Six percent took the stairs with the display of the health benefits sign (difference, 1.4 percentage points [CI, 0.3 to 2.4 percentage points]; NNT, 71), and 6.1% took the stairs in response to the weight-control sign (difference, 1.5 percentage points [CI, 0.3 to 2.7 percentage points]; NNT, 66), significantly increasing stair use relative to the baseline value (P = 0.015). No statistically significant difference in stair use was found between the health benefits sign and weight-control sign (difference, 0.1 percentage points [CI, 3.4 to 3.6 percentage points]). A similar pattern emerged among persons judged to be 40 years of age or older. At baseline, 5.1% of persons took the stairs; when the health benefits sign was erected, 8.1% chose to climb the stairs (difference, 3.0 percentage points [CI, 1.7 to 4.3 percentage points]; NNT, 33), and the weight-control sign increased stair use to 8.7% (difference, 3.6 percentage points [CI, 2.1 to 5.1 percentage points]; NNT, 28). Stair use did not significantly differ between the two signs (difference, 0.6 percentage points [CI, 0.8 to 2.1 percentage points]). Older shoppers were more likely than younger shoppers to take the stairs in response to both the health benefits sign (difference, 2.1 percentage points [CI, 0.9 to 3.2 percentage points]) and the weight-control sign (difference, 2.6 percentage points [CI, 1.1 to 4.1 percentage points]) (Figure 1). Figure 1. Patterns of stair use among shoppers judged to be younger than 40 years of age (white bars) or 40 years of age or older (striped bars). Body Weight Persons were stratified by body weight (not overweight or overweight). At baseline, 5.4% of shoppers judged to be not overweight used the stairs. The health benefits sign increased stair use to 7.2% (difference, 1.8 percentage points [CI, 1.2 to 4.7 percentage points]; NNT, 55), and the weight-control sign increased stair use to 6.9% (difference, 1.5 percentage points [CI, 0.3 to 2.6 percentage points]; NNT, 66). The same pattern emerged among persons judged to overweight: The health benefits sign significantly increased stair use from 3.8% to 6.3% [difference, 2.5 percentage points (CI, 1.2 to 3.7 percentage points); NNT, 40], and the weight-control sign increased stair use from 3.8% to 7.7% (difference, 3.9 percentage points [CI, 1.2 to 7.0 percentage points]; NNT, 40). In persons judged not to be overweight, stair use did not differ significantly between the health benefits sign (7.2%) and the weight-control sign (6.9%) (difference