Recent technological advances allow for field-based data collection of accelerometers in community-based studies. Mail-based administration can markedly reduce the cost and logistic challenges and burden associated with in-person data collection. It necessitates, however, other resources, such as phone calls and mailed reminder prompts, to increase protocol compliance and data recovery. Additionally, lost accelerometers can impact the study’s budget and its internal validity due to missing data. In this article, we present an applied methodological approach used to define thresholds (or cutoff points) at which pursuing unreturned accelerometers is a worthwhile versus futile pursuit. This methodological approach was designed, specifically, to maximize scalability across multiple sectors. We used data from an on-going study that administered accelerometers through the mail to illustrate and encourage investigators to replicate the approach for use in their own studies. In heterogeneous study samples, investigators might consider repeating this approach by study-relevant strata to refine thresholds and improve the return percentages of data collection instruments, minimize the potential missing data, and optimize study staff time and resources.
Gregory Knell, Deborah Salvo, Kerem Shuval, Casey Durand, Harold W. Kohl III and Kelley P. Gabriel
Anna K. Porter, Krystin J. Matthews, Deborah Salvo and Harold W. Kohl III
Most US adolescents do not meet guidelines of at least 60 daily minutes of moderate- to vigorous-intensity physical activity. In addition, sedentary behaviors among this age group are of increasing concern. This study examined the association of movement behaviors with cardiovascular fitness among US adolescents.
Data from the 2012 NHANES National Youth Fitness Survey were used to assess the association of movement behaviors (physical activity, sedentary time, screen time) with cardiovascular fitness among adolescent males and females. Multiple logistic regressions were used to test the independent and interactive effects of movement behaviors on cardiovascular fitness.
Among females, physical activity was directly associated with cardiovascular fitness; no significant association was observed between sedentary behaviors and CVF. Among males, sedentary time moderated the relationship between physical activity and cardiovascular fitness, such that a significant, direct association was only observed among those with high sedentary time (OR: 5.01; 95% CI: 1.60, 15.70).
Results from this cross-sectional analysis suggest that among female US adolescents, physical activity, but not sedentary behavior, is associated with cardiovascular fitness. Among males, the interaction between physical activity and sedentary time seems to be important for cardiovascular fitness. Longitudinal studies are warranted to confirm these findings.
Deborah Salvo, Rodrigo S. Reis, Adriano A.F. Hino, Pedro C. Hallal and Michael Pratt
There is little understanding about which sets of environmental features could simultaneously predict intensity-specific leisure-time physical activity (LTPA) among Brazilians. The objectives were to identify the environmental correlates for intensity-specific LTPA, and to build the best-fit linear models to predict intensity-specific LTPA among adults of Curitiba, Brazil.
Cross sectional study in Curitiba, Brazil (2009, n = 1461). The International Physical Activity Questionnaire and Abbreviated Neighborhood Environment Assessment Scale were used. Ninety-two perceived environment variables were categorized in 10 domains. LTPA was classified as walking for leisure (LWLK), moderate-intensity leisure-time PA (MLPA), vigorous-intensity leisure-time PA (VLPA), and moderate-to-vigorous intensity leisure-time PA (MVLPA). Best fitting linear predictive models were built.
Forty environmental variables were correlated to at least 1 LTPA outcome. The variability explained by the 4 best-fit models ranged from 17% (MLPA) to 46% (MVLPA). All models contained recreation areas and aesthetics variables; none included residential density predictors. At least 1 neighborhood satisfaction variable was present in each of the intensity-specific models, but not for overall MVLPA.
This study demonstrates the simultaneous effect of sets of perceived environmental features on intensity-specific LTPA among Brazilian adults. The differences found compared with high-income countries suggest caution in generalizing results across settings.
Alejandra Jáuregui, Catalina Medina, Deborah Salvo, Simon Barquera and Juan A. Rivera-Dommarco
Travel to school offers a convenient way to increase physical activity (PA) levels in youth. We examined the prevalence and correlates of active commuting to school (ACS) in a nationally representative sample of Mexican adolescents. A secondary objective was to explore the association between ACS and BMI status.
Using data of adolescents (10–14 years old) from the 2012 Mexican National Health and Nutrition Survey (n = 2952) we ran multivariate regression models to explore the correlates of ACS and to test the association between ACS and BMI z-score or overweight/obesity. Models were adjusted for potential confounders and design effect.
70.8% of adolescents engaged in ACS (walking: 68.8%, bicycling: 2.0%). ACS was negatively associated with travel time, age, mother’s education level, household motor vehicle ownership, family socioeconomic status, and living in urban areas or the North region of the country (P < .05). Time in ACS was negatively associated with overweight/obesity: Each additional minute of ACS was associated with a 1% decrease in the odds for being overweight or obese (P < .05).
Potential correlates of ACS that may result in benefits for Mexican adolescents are identified. More studies on this relationship are needed to develop interventions aimed at increasing PA through ACS in Mexico.
Gregory Knell, Henry S. Brown, Kelley P. Gabriel, Casey P. Durand, Kerem Shuval, Deborah Salvo and Harold W. Kohl III
Background: Improving sidewalks may encourage physical activity by providing safe, defined, and connected walking spaces. However, it is unknown if reduced health care expenditures assumed by increased physical activity offset the investment for sidewalk improvements. Methods: This cost-effectiveness analysis of sidewalk improvements in Houston, TX, was among adults enrolled in the Houston Travel-Related Activity in Neighborhoods Study, 2013–2017 . The 1-year change in physical activity was measured using self-report (n = 430) and accelerometry (n = 228) and expressed in metabolic equivalent (MET) hours per year (MET·h·y−1). Cost-effectiveness ratios were calculated by comparing annualized sidewalk improvement costs (per person) with 1-year changes in physical activity. Results: The estimated cost-effectiveness ratio were $0.01 and −$0.46 per MET·h·y−1 for self-reported and accelerometer-derived physical activity, respectively. The cost-effectiveness benchmark was $0.18 (95% confidence interval, $0.06–$0.43) per MET·h·y−1 gained based on the volume of physical activity necessary to avoid health care costs. Conclusions: Improving sidewalks was cost-effective based on self-reported physical activity, but not cost-effective based on accelerometry. Study findings suggest that improving sidewalks may not be a sufficient catalyst for changing total physical activity; however, other benefits of making sidewalks more walkable should be considered when deciding to invest in sidewalk improvements.
Jacqueline Kerr, James F. Sallis, Neville Owen, Ilse De Bourdeaudhuij, Ester Cerin, Takemi Sugiyama, Rodrigo Reis, Olga Sarmiento, Karel Frömel, Josef Mitáš, Jens Troelsen, Lars Breum Christiansen, Duncan Macfarlane, Deborah Salvo, Grant Schofield, Hannah Badland, Francisco Guillen-Grima, Ines Aguinaga-Ontoso, Rachel Davey, Adrian Bauman, Brian Saelens, Chris Riddoch, Barbara Ainsworth, Michael Pratt, Tom Schmidt, Lawrence Frank, Marc Adams, Terry Conway, Kelli Cain, Delfien Van Dyck and Nicole Bracy
National and international strategies to increase physical activity emphasize environmental and policy changes that can have widespread and long-lasting impact. Evidence from multiple countries using comparable methods is required to strengthen the evidence base for such initiatives. Because some environment and policy changes could have generalizable effects and others may depend on each country’s context, only international studies using comparable methods can identify the relevant differences.
Currently 12 countries are participating in the International Physical Activity and the Environment Network (IPEN) study. The IPEN Adult study design involves recruiting adult participants from neighborhoods with wide variations in environmental walkability attributes and socioeconomic status (SES).
Eleven of twelve countries are providing accelerometer data and 11 are providing GIS data. Current projections indicate that 14,119 participants will provide survey data on built environments and physical activity and 7145 are likely to provide objective data on both the independent and dependent variables. Though studies are highly comparable, some adaptations are required based on the local context.
This study was designed to inform evidence-based international and country-specific physical activity policies and interventions to help prevent obesity and other chronic diseases that are high in developed countries and growing rapidly in developing countries.