AbstractBackgroundMost preschool centers provide two 30-min sessions of gross-motor/outdoor playtime per preschool day. Within this time frame, children accumulate most of their activity within the first 10 min. This paper describes the design and baseline participant characteristics of the Short bouTs of Exercise for Preschoolers (STEP) study. The STEP study is a cluster randomized controlled study designed to examine the effects of short bouts of structured physical activity (SBS-PA) implemented within the classroom setting as part of designated gross-motor playtime on during-school physical activity (PA) in preschoolers.Methods/DesignTen preschool centers serving low-income families were randomized into SBS-PA versus unstructured PA (UPA). SBS-PA schools were asked to implement age-appropriate 10 min structured PA routines within the classroom setting, twice daily, followed by 20 min of usual unstructured playtime. UPA intervention consisted of 30 min of supervised unstructured free playtime twice daily. Interventions were implemented during the morning and afternoon designated gross-motor playtime for 30 min/session, five days/week for six months. Outcome measures were between group difference in during-preschool PA (accelerometers and direct observation) over six-months. Ten preschool centers, representing 34 classrooms and 315 children, enrolled in the study. The average age and BMI percentile for the participants was 4.1 ± 0.8 years and 69th percentile, respectively. Participants spent 74% and 6% of their preschool day engaged in sedentary and MVPA, respectively.DiscussionResults from the STEP intervention could provide evidence that a PA policy that exposes preschoolers to shorter bouts of structured PA throughout the preschool day could potentially increase preschoolers’ PA levels.Trial registrationClinicaltrials.gov, NCT01588392

Objective

Both coronary artery calcification (CAC) and the ankle brachial index (ABI) are measures of subclinical atherosclerotic disease. The influence of physical activity on the longitudinal change in these measures remains unclear. To assess this relation we examined the association between these measures and self-reported physical activity in the Multi-Ethnic Study of Atherosclerosis (MESA).

Methods

At baseline, the MESA participants were free of clinically evident cardiovascular disease. We included all participants with an ABI between 0.90 and 1.40 (n = 5656). Predictor variables were based on self-reported measures with physical activity being assessed using the Typical Week Physical Activity Survey from which metabolic equivalent-minutes/week of activity were calculated. We focused on physical activity intensity, intentional exercise, sedentary behavior, and conditioning. Incident peripheral artery disease (PAD) was defined as the progression of ABI to values below 0.90 (given the baseline range of 0.90-1.40). Incident CAC was defined as a CAC score >0 Agatston units upon follow up with a baseline score of 0 Agatston units.

Results

Mean age of participants was 61 years, 53% were female, and mean body mass index was 28 kg/m(2). After adjusting for traditional cardiovascular risk factors and socioeconomic factors, intentional exercise was protective for incident peripheral artery disease (Relative Risk (RR) = 0.85, 95% Confidence Interval (CI): 0.74-0.98). After adjusting for traditional cardiovascular risk factors and socioeconomic factors, there was a significant association between vigorous PA and incident CAC (RR = 0.97, 95% CI: 0.94-1.00). There was also a significant association between sedentary behavior and increased amount of CAC among participants with CAC at baseline (Δlog (Agatston Units + 25) = 0.027, 95% CI 0.002, 0.052).

Conclusions

These data suggest that there is an association between physical activity/sedentary behavior and the progression of two different measures of subclinical atherosclerotic disease.

Objective

While behavioral change is necessary to reverse the obesity epidemic, it can be difficult to achieve and sustain in unsupportive residential environments. This study hypothesized that environmental resources supporting walking and a healthy diet are associated with reduced obesity incidence.

Design and methods

Data came from 4,008 adults aged 45-84 at baseline who participated in a neighborhood ancillary study of the Multi-Ethnic Study of Atherosclerosis. Participants were enrolled at six study sites at baseline (2000-2002) and neighborhood scales were derived from a supplementary survey that asked community residents to rate availability of healthy foods and walking environments for a 1-mile buffer area. Obesity was defined as BMI ≥ 30 kg/m(2) . Associations between incident obesity and neighborhood exposure were examined using proportional hazards and generalized linear regression.

Results

Among 4,008 nonobese participants, 406 new obesity cases occurred during 5 years of follow-up. Neighborhood healthy food environment was associated with 10% lower obesity incidence per s.d. increase in neighborhood score. The association persisted after adjustment for baseline BMI and individual-level covariates (hazard ratio (HR) 0.88, 95% confidence interval (CI): 0.79, 0.97), and for correlated features of the walking environment but CIs widened to include the null (HR 0.89, 95% CI: 0.77, 1.03). Associations between neighborhood walking environment and lower obesity were weaker and did not persist after adjustment for correlated neighborhood healthy eating amenities (HR 0.98, 95% CI: 0.84, 1.15).

Conclusions

Altering the residential environment so that healthier behaviors and lifestyles can be easily chosen may be a precondition for sustaining existing healthy behaviors and for adopting new healthy behaviors.