Bravarta et al. (2000) pedometer review
Discussion Questions
- What is a meta-analysis? How were the results from multiple studies combined and analyzed in this study?
A meta-analysis is a statistical technique for combining the findings from independent studies. 4 categories of variables from each of the included studies were extracted. For each of the included studies, we calculated 2 effect sizes for each of the outcomes of interest: the mean difference and the standardized mean differences. Using meta-regression weighted by the sample size, calculations of the summary effect of the physical activity and participant characteristic variables on the outcome variables were performed. Researchers removed each study individually to evaluate the study’s effect on the summary estimates. In the end, 26 studies met the inclusion criteria after being assessed for bias, relapsing data, validity, and reliability. These studies were included in the meta-analysis.
- How many studies were considered RCT’s and how many were classified as observational studies? What distinguished RCT’s from observational studies?
Fourteen of the included studies were randomized controlled trials, and twelve studies were single-group observational studies. For randomized controlled trials, calculations for the difference in the pre-intervention and the post-intervention changes in outcomes between the intervention and control participants were included. Differences were noted considering RCT participants randomly assigned to pedometer use and the group assigned as control participants. The summary increase in physical activity among the intervention participants was 2491 steps per day more than the control participants. Among the observational studies, the pedometer users significantly increased their physical activity by 2183 steps per day over baseline. That is calculated out to be a 26.9% increase in physical activity over baseline on average. Despite differences amongst the RCT’s and the observational studies, the pedometer itself was associated with greater physical activity.
- On average, what is the effect of pedometer use on physical activity levels? Is it significant from a public health perspective? Explain your answer.
Generally, younger pedometer users and those with less baseline activity had the greatest increase in physical activity. Sex, BMI, and ethnicity/race were not significant predictors of increased activity. Having a step goal or step diary significantly improved physical activity. Another predictor of increased physical activity was having the intervention in a setting other than the workplace. Limitations include that majority of participants are female, and the minority of the participants were over the age of 60. The effect of pedometer use on physical activity levels is significant from a public health perspective. Physical activity is linked to associated health benefits and pedometer use is linked to increased physical activity. It’s a cheap, and easy alternative to other expensive fitness equipment. It keeps users accountable by showing a goal step count and counting the steps out. These are all important to achieving fitness levels. Using the pedometer increased physical activity and that is the first major step towards a healthier life.
- What was the impact of pedometer-based activity interventions on health outcomes? Were the changes significant from a public health perspective?
Pedometer use was related to favorable health outcomes for both the observational and RCT intervention group. Intervention participants significantly decreased BMI, their systolic blood pressure by 3.8 mm Hg, and their diastolic blood pressure by 0.3 mm Hg. Other benefits included changes in low-density lipoprotein levels and some participants experienced changes in their serum glucose concentrations. However, many participants in the intervention group had normal baseline values for their serum glucose concentrations and therefore didn’t experience a significant difference post-test. These inexpensive, small devices are associated with significant increases in physical activity and some key health outcomes, at least in the short term. As seen in the results, subject characteristics such as blood pressure, BMI, and other health benefits improved. In fact, BMI decreased in subjects despite noticeable activity increases detected by the pedometer. This means that either subjects participated in activities not measurable by the pedometer, subjects decreased their total caloric intake, or both.
- What are the gaps in the scientific knowledge base regarding the use of pedometers to increase physical activity?
Studies were relatively small and interventions were of relatively short duration and heterogeneous in their design. Few studies evaluated more than one of the outcomes of interest or provided detailed information about their participants. Also, because many interventions included the use of 2 or more components, the independent contribution of any one of these components is difficult to establish. Pedometers are used in these studies both as an intervention to motivate physical activity and as a tool to measure steps per day and participants may have increased their physical activity just by virtue of knowing that they are being monitored. Since no long-term follow-up was conducted, the increased physical activity due to being monitored can’t be ruled out. Only 15% of the participants were men, and only five studies involved participants with a mean age older than 60 years. Therefore, the generalizability of the results to older and male populations is limited.
Due to these limitations large, randomized controlled trials of men and women over a range of ages in the outpatient setting should be conducted to discover the full potential benefits of pedometers. These trials should make the following comparisons: pedometer use in which participants can see their daily step counts vs. pedometer use in which they are blinded to their daily step counts. Pedometer use with versus pedometer use without a step goal must be compared. Pedometer use with or without physical activity counseling and feedback. Lastly, pedometer use with versus without the use of step diaries. After all of these are compared, a longer intervention a long with a follow-up study should be done. This will identify whether physical activity and related health benefits are solidified long-term or only a possible outcome of the monitoring of the intervention.
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