Cardiometabolic risk among rural Native American adults in a large multilevel multicomponent intervention trial.

This cross-sectional analysis of the baseline evaluation sample of the Obesity Prevention and Evaluation of InterVention Effectiveness in Native Americans 2 (OPREVENT2) study included 601 Native American adults ages 18-75 living in rural reservation communities in the Midwest and Southwest United States. Participants completed a self-report questionnaire for individual and family history of hypertension, heart disease, diabetes and obestiy. Body mass index (BMI), percent body fat, and blood pressure were measured by trained research staff. About 60% of respondents had a BMI >30 kg/m2. Approximately 80% had a waist-to-hip ratio and percent body fat classified as high risk, and nearly 64% had a high-risk blood pressure measurement. Although a large proportion of participants reported a family history of chronic disease and had measurements that indicated elevated risk, relatively few had a self-reported diagnosis of any chronic disease. Future studies should examine potential connections between healthcare access and discordance in self-reported versus measured disease risks and diagnoses.

Knowledge, attitudes, and behaviors with mask use and vaccines for COVID-19 prevention at 13 colleges and universities, April 2021.

Objectives: To understand college and university student knowledge, attitudes, and behaviors (KAB) regarding COVID-19 prevention strategies. Methods: Thirteen colleges and universities volunteered to conduct an anonymous electronic survey in April 2021 to assess students' KAB about mask use and vaccination to prevent COVID-19. Results: Three-quarters of students indicated they "Always" wore a mask correctly when in public indoor places. Of those not yet vaccinated, 55% expressed concern about unknown side effects. Over half of students were unsure or believe they do not need to continue wearing masks after vaccination and older students more likely to be vaccinated. There was a significant inverse correlation between intention of getting vaccinated and intention to attend a large indoor party without a mask. Conclusions: Colleges and universities are important to community efforts to slow the COVID-19 pandemic. The KAB findings can inform approaches to increase overall mask use and vaccination uptake among young students.

Exposure to a Multilevel, Multicomponent Obesity Prevention Intervention (OPREVENT2) in Rural Native American Communities: Variability and Association with Change in Diet Quality.

The OPREVENT2 obesity prevention trial was a multilevel multicomponent (MLMC) intervention implemented in rural Native American communities in the Midwest and Southwest U.S. Intervention components were delivered through local food stores, worksites, schools, community action coalitions, and by social and community media. Due to the complex nature of MLMC intervention trials, it is useful to assess participants' exposure to each component of the intervention in order to assess impact. In this paper, we present a detailed methodology for evaluating participant exposure to MLMC intervention, and we explore how exposure to the OPREVENT2 trial impacted participant diet quality. There were no significant differences in total exposure score by age group, sex, or geographic region, but exposure to sub-components of the intervention differed significantly by age group, sex, and geographical region. Participants with the highest overall exposure scores showed significantly more improvement in diet quality from baseline to follow up compared to those who were least exposed to the intervention. Improved diet quality was also significantly positively associated with several exposure sub-components. While evaluating exposure to an entire MLMC intervention is complex and imperfect, it can provide useful insight into an intervention's impact on key outcome measures, and it can help identify which components of the intervention were most effective.

Validating accelerometry as a measure of physical activity and energy expenditure in chronic stroke.

BACKGROUND: Accelerometers can objectively measure steps taken per day in individuals without gait deficits, but accelerometers also have the ability to estimate frequency, intensity, and duration of physical activity. However, thresholds to distinguish varying levels of activity intensity using the Actical brand accelerometer are standardized only for the general population and may underestimate intensity in stroke. OBJECTIVE: To derive Actical activity count thresholds specific to stroke disability for use in more accurately gauging time spent at differing activity levels. METHODS: Men (n = 18) and women (n = 10) with chronic hemiparetic gait (4 ± 2 years latency, 43% Caucasian, 56% African-American, ages of 47-83 years, BMI 19-48 kg/m2) participated in the study. Actical accelerometers were placed on the non-paretic hip to obtain accelerometry counts during eight activities of varying intensity: (1) watching TV; (2) seated stretching; (3) standing stretching; (4) floor sweeping; (5) stepping in place; (6) over-ground walking; (7) lower speed treadmill walking (1.0 mph at 4% incline); and (8) higher speed treadmill walking (2.0 mph at 4% incline). Simultaneous portable monitoring (Cosmed K4b2) enabled quantification of energy cost for each activity in metabolic equivalents (METs, or oxygen consumption in multiples of resting level). Measurements were obtained for 10 min of standard rest and 5 min during each of the eight activities. RESULTS: Regression analysis yielded the following new stroke-specific Actical minimum thresholds: 125 counts per minute (cpm) for sedentary/light activity, 667 cpm for light/moderate activity, and 1546 cpm for moderate/vigorous activity. CONCLUSION: Our revised cut points better reflect activity levels after stroke and suggest significantly lower thresholds relative to those observed for the general population of healthy individuals. We conclude that the standard, commonly applied Actical thresholds are inappropriate for this unique population.

Toddler physical activity study: laboratory and community studies to evaluate accelerometer validity and correlates.

BACKGROUND: Toddlerhood is an important age for physical activity (PA) promotion to prevent obesity and support a physically active lifestyle throughout childhood. Accurate assessment of PA is needed to determine trends/correlates of PA, time spent in sedentary, light, or moderate-vigorous PA (MVPA), and the effectiveness of PA promotion programs. Due to the limited availability of objective measures that have been validated and evaluated for feasibility in community studies, it is unclear which subgroups of toddlers are at the highest risk for inactivity. Using Actical ankle accelerometry, the objectives of this study are to develop valid thresholds, examine feasibility, and examine demographic/ anthropometric PA correlates of MVPA among toddlers from low-income families. METHODS: Two studies were conducted with toddlers (12-36 months). Laboratory Study (n = 24)- Two Actical accelerometers were placed on the ankle. PA was observed using the Child Activity Rating Scale (CARS, prescribed activities). Analyses included device equivalence reliability (correlation: activity counts of two Acticals), criterion-related validity (correlation: activity counts and CARS ratings), and sensitivity/specificity for thresholds. Community Study (n = 277, low-income mother-toddler dyads recruited)- An Actical was worn on the ankle for > 7 days (goal >5, 24-h days). Height/weight was measured. Mothers reported demographics. Analyses included frequencies (feasibility) and stepwise multiple linear regression (sMLR). RESULTS: Laboratory Study- Acticals demonstrated reliability (r = 0.980) and validity (r = 0.75). Thresholds demonstrated sensitivity (86 %) and specificity (88 %). Community Study- 86 % wore accelerometer, 69 % had valid data (mean = 5.2 days). Primary reasons for missing/invalid data: refusal (14 %) and wear-time ≤2 days (11 %). The MVPA threshold (>2200 cpm) yielded 54 min/day. In sMLR, MVPA was associated with age (older > younger, ß = 32.8, p < 0.001), gender (boys > girls, ß = -11.21, p = 0.032), maternal MVPA (ß = 0.44, p = 0.002) and recruitment location (suburban > urban, ß = 19.6, p < 0.001), or race (non-Black > Black, ß = 18.5, p = 0.001). No association with toddler weight status. CONCLUSIONS: Ankle accelerometry is a valid, reliable, and feasible method of assessing PA in community studies of toddlers from low-income families. Sub-populations of toddlers may be at increased risk for inactivity, including toddlers that are younger, female, Black, those with less active mothers, and those living in an urban location.

Self-Reported Physical Activity Among American Indian Adults From Two Diverse Regions.

PURPOSE: Physical activity may be a protective factor against the disproportionate rates of chronic diseases faced by American Indians. Nevertheless, few studies report any cultural adoptions made to capture physical activity behaviors among this hard-to-reach population. Existing studies reporting the prevalence of physical activity among American Indians are often aggregated and tend to obscure regional, local, and tribal-level variations. This study examines the prevalence of physical activity and inactivity levels, along with associated factors, among rural dwelling American Indian adults from 2 distinct regions. METHODS: Baseline self-reported data were collected using a culturally modified version of the International Physical Activity Questionnaire (IPAQ) short form during the Obesity Research Prevention and Evaluation of Intervention Effectiveness in Native North Americans trial (OPREVENT) among rural American Indian adults (aged 18-75 years) from 5 tribal communities in Michigan and New Mexico. FINDINGS: Most participants were classified as moderately physically active (43.5%), and the majority reported access to physical activity facilities (83.5%). Michigan participants reported engaging in more moderate and total physical activity than those in New Mexico (P < .001) and reported spending less time sitting (P < .001). CONCLUSIONS: Differences in physical activity among the American Indian communities may be due to regional variations in occupations, climate, and tribal and community support and infrastructure. The unexpected high level of activity evokes uncertainty in the accuracy and appropriateness of the data collection instrument. Research is needed to understand culturally appropriate approaches to measure physical activity and inactivity among rural American Indians.

Increased Energy Cost of Mobility in Chronic Stroke.

The purpose of this study was to compare the energy cost of completing mobility-related activities in chronic stroke to the estimated energy cost found in the compendium of physical activities, a resource that estimates and classifies energy cost of various human physical activities. Men (n=18) and women (n=10) with chronic hemiparetic gait (stroke latency: 4 ± 2 years, age: 60.4 ± 1.6 years, BMI: 31.5 ± 1.1 kg/m2) participated in the study. Portable energy cost monitoring (COSMED K4b2) was performed during five mobility activities of varying intensity to determine metabolic equivalents (METs, or oxygen consumption in multiples of resting level) for each activity. The METs achieved during the five activities were compared to the following compendium MET values for: 1) floor sweeping; 2) stepping in place; 3) over-ground walking; 4) lower speed treadmill walking (1.0 mph at 4% incline); and 5) higher speed treadmill walking (2.0 mph at 4% incline). Measurements were obtained for 10 min at rest and 5 minutes during each of the five activities. The energy cost of rest was only 85% of Compendium METS, while mobility-related activities were ~1.25-1.50 fold greater when measured in stroke vs. Compendium METS for all measures (P's<0.05), except floor sweeping, which was similar between groups. These data indicate that MET levels provided in the compendium are not applicable to chronic stroke survivors as they overestimate energy expenditure at rest and underestimate energy expenditure during physical activity, indicating poor efficiency in movement, thus elevating the oxygen cost of completing general daily activities.

Ankle Accelerometry for Assessing Physical Activity Among Adolescent Girls: Threshold Determination, Validity, Reliability, and Feasibility.

PURPOSE: Ankle accelerometry allows for 24-hr data collection and improves data volume/integrity versus hip accelerometry. Using Actical ankle accelerometry, the purpose of this study was to (a) develop sensitive/specific thresholds, (b) examine validity/reliability, (c) compare new thresholds with those of the manufacturer, and (d) examine feasibility in a community sample (low-income, urban adolescent girls). METHOD: Two studies were conducted with 6th- through 7th-grade girls (aged 10-14 years old): First was a laboratory study (n = 24), in which 2 Actical accelerometers were placed on the ankle and worn while measuring energy expenditure (Cosmed K4b2, metabolic equivalents [METs]) during 10 prescribed activities. Analyses included device equivalence reliability (intraclass correlation coefficient [ICC], activity counts of 2 Acticals), criterion-related validity (correlation, activity counts and METs), and calculations of sensitivity, specificity, kappa, and receiver-operating characteristic curves for thresholds. The second was a free-living study (n = 459), in which an Actical was worn for more than 7 days on the ankle (full 24-hr days retained). Analyses included feasibility (frequencies, missing data) and paired t tests (new thresholds vs. those of the manufacturer). RESULTS: In the laboratory study, the Actical demonstrated reliability (ICC = .92) and validity (r = .81). Thresholds demonstrated sensitivity (91%), specificity (84%), kappa = .73 (p = .043), area under curve range = .81-.97. In the free-living study, 99.6% of participants wore the accelerometer; 84.1% had complete/valid data (mean = 5.7 days). Primary reasons for missing/invalid data included: improper programming/documentation (5.2%), failure to return device (5.0%), and wear-time ≤ 2 days (2.8%). The moderate-to-vigorous physical activity threshold (> 3,200 counts/minute) yielded 37.2 min/day, 2 to 4.5 times lower than that of the manufacturer's software (effect size = 0.74-4.05). CONCLUSIONS: Validity, reliability, and feasibility evidences support Actical ankle accelerometry to assess physical activity in community studies of adolescent girls. When comparing manufacturers' software versus new thresholds, a major difference was observed.

Multilevel correlates of physical activity for early, mid, and late adolescent girls.

BACKGROUND: We examined associations among multilevel variables and girls' physical activity to determine whether they vary at different adolescent ages. METHODS: All field sites of the Trial of Activity for Adolescent Girls contributed participants from 6th (n = 1576) and 8th grades (n = 3085). The Maryland site contributed an 11th grade sample (n = 589). Questionnaires were used to obtain demographic and psychosocial information (individual- and social-level variables); height, weight, and triceps skinfold to assess body composition; interviews and surveys for school-level data; and geographical information systems and self-report for neighborhood-level variables. Moderate to vigorous physical activity minutes (MVPA) were assessed from accelerometers. Mixed models (13 individual, 5 social, 15 school, 12 neighborhood variables) were used to determine multilevel associations. RESULTS: Variables at individual, social, school, and neighborhood levels were associated with MVPA, but differed across grades. Lower percent body fat, higher social support from friends, and lower school math scores were associated with higher MVPA at 6th and 8th grade. Higher physical activity self-efficacy was associated with higher MVPA at 11th grade. Only lower physical activity barriers were associated with higher MVPA at all grades. CONCLUSION: MVPA is a complex behavior with fluid, multilevel correlates that differ among girls across middle and high school.

Comparison of BMI and physical activity between old order Amish children and non-Amish children.

OBJECTIVE: The Old Order Amish (OOA) is a conservative Christian sect of European origin living in Pennsylvania. Diabetes is rare in adult OOA despite a mean BMI rivaling that in the general U.S. non-Hispanic white population. The current study examines childhood factors that may contribute to the low prevalence of diabetes in the OOA by comparing OOA children aged 8-19 years with National Health and Nutrition Examination Survey (NHANES) data and children from Maryland's Eastern Shore (ES), a nearby, non-Amish, rural community. We hypothesized that pediatric overweight is less common in OOA children, that physical activity (PA) and BMI are inversely correlated, and that OOA children are more physically active than ES children. RESEARCH DESIGN AND METHODS: We obtained anthropometric data in 270 OOA children and 229 ES children (166 non-Hispanic white, 60 non-Hispanic black, 3 Hispanic). PA was measured by hip-worn accelerometers in all ES children and in 198 OOA children. Instrumentation in 43 OOA children was identical to ES children. RESULTS: OOA children were approximately 3.3 times less likely than non-Hispanic white ES children and NHANES estimates to be overweight (BMI ≥85th percentile, Centers for Disease Control and Prevention). Time spent in moderate/vigorous PA (MVPA) was inversely correlated to BMI z-score (r = -0.24, P = 0.0006). PA levels did not differ by ethnicity within the ES group, but OOA children spent an additional 34 min/day in light activity (442 ± 56 vs. 408 ± 75, P = 0.005) and, impressively, an additional 53 min/day in MVPA (106 ± 54 vs. 53 ± 32, P < 0.0001) compared with ES children. In both groups, boys were more active than girls but OOA girls were easily more active than ES boys. CONCLUSIONS: We confirmed all three hypotheses. Together with our previous data, the study implies that the OOA tend to gain their excess weight relatively late in life and that OOA children are very physically active, both of which may provide some long-term protection against diabetes.

A cross-sectional and longitudinal study of travel by walking before and after school among eighth-grade girls.

PURPOSE: To examine "travel by walking" (TBW) before and after school among eighth-grade girls. METHODS: Participants attended 36 middle schools from Arizona, Maryland, Minnesota, Louisiana, California, and South Carolina participating in the Trial of Activity for Adolescent Girls. The cross-sectional sample consisted of 3,076 eighth-grade girls, and the longitudinal sample included 1,017 girls who participated in both sixth and eighth grades. Before- or after-school TBW status was determined from the 3-Day Physical Activity Recall. The main outcomes were body mass index and physical activity, which was measured by accelerometry, estimated for total physical activity (light, moderate, vigorous) and moderate-to-vigorous physical activity (MVPA). RESULTS: Eighth-grade girls who reported TBW had 4 more minutes (95% confidence interval = 2.1-6.1) of MVPA before and after school than nonwalkers, and 2 more minutes of MVPA (95% confidence interval = 1.1-3.1) on an average weekday. In the longitudinal sample, girls who reported TBW before and after school in both sixth and eighth grades (consistent walkers) accumulated more minutes of MVPA for an average weekday than inconsistent walkers in both sixth (27 ± 2.2 vs. 25 ± 1.9 minutes; p = .03) and eighth (28 ± 2.6 vs. 25 ± 2.3 minutes; p = .003) grades. There were no differences in body mass index by walking status. CONCLUSIONS: Adolescent girls who reported TBW before and after school accumulated more minutes of MVPA than nonwalkers. Efforts to prevent the decline in walking to school in middle school girls could contribute to their overall physical activity.

Challenge! Health promotion/obesity prevention mentorship model among urban, black adolescents.

OBJECTIVES: The objective of this study was to evaluate a 12-session home/community-based health promotion/obesity prevention program (Challenge!) on changes in BMI status, body composition, physical activity, and diet. METHODS: A total of 235 black adolescents (aged 11-16 years; 38% overweight/obese) were recruited from low-income urban communities. Baseline measures included weight, height, body composition, physical activity (PA), and diet. PA was measured by 7-day play-equivalent physical activity (> or =1800 activity counts per minute). Participants were randomly assigned to health promotion/obesity prevention that is anchored in social cognitive theory and motivational interviewing and was delivered by college-aged black mentors or to control. Postintervention (11 months) and delayed follow-up (24 months) evaluations were conducted. Longitudinal analyses used multilevel models with random intercepts and generalized estimating equations, controlling for baseline age/gender. Stratified analyses examined baseline BMI category. RESULTS: Retention was 76% over 2 years; overweight/obese status declined 5% among intervention adolescents and increased 11% among control adolescents. Among overweight/obese youth, the intervention reduced total percentage of body fat and fat mass and increased fat-free mass at delayed follow-up and increased play-equivalent physical activity at postintervention but not at delayed follow-up. Intervention adolescents declined significantly more in snack/dessert consumption than control adolescents at both follow-up evaluations. CONCLUSIONS: At postintervention, there were intervention effects on diet and PA but not BMI category or body composition. At delayed follow-up, dietary changes were sustained and the intervention prevented an increase in BMI category. Body composition was improved for overweight/obese youth. Changes in body composition follow changes in diet and PA and may not be detected immediately after intervention.

Associations between patterns of objectively measured physical activity and risk factors for the metabolic syndrome.

PURPOSE: To determine whether certain patterns of objectively measured physical activity (PA) are associated with the risk factors for or the diagnosis of the metabolic syndrome (MS). DESIGN: Latent class analysis, including assessment of the associations between latent PA classes and risk factors for the MS. SETTING: Random sample from throughout the United States using data from the 2003-2004 National Health and Nutrition Examination Survey. SUBJECTS: A total of 3458 civilian adult noninstitutionalized U.S. citizens. MEASURES: Daily minutes of moderate-to-vigorous PA across a 7-day week based on accelerometer measurements, as well as high blood pressure, blood glucose levels, triglyceride levels, and body mass index, along with low levels of high density lipoproteins, using clinical cut points. RESULTS: Membership in the more active PA classes was consistently associated with lower odds of all risk factors for the MS. However, when participants were categorized into quartiles of the coefficients of variation of PA across 7 days, few differences were seen in any of the risk factors. CONCLUSIONS: Accumulating the total weekly recommended amount of PA is consistently associated with positive health profiles, and more PA than the recommended amounts may be even better. However, the manner in which this activity is accumulated, either spread over most days of the week or compressed into just a couple of days, may have similar associations with the risk factors for the MS.

Progressive adaptive physical activity in stroke improves balance, gait, and fitness: preliminary results.

PURPOSE: We conducted a non-controlled pilot intervention study in stroke survivors to examine the efficacy of low-intensity adaptive physical activity to increase balance, improve walking function, and increase cardiovascular fitness and to determine whether improvements were carried over into activity profiles in home and community. METHOD: Adaptive physical activity sessions were conducted 3 times/week for 6 months. The main outcomes were Berg Balance Scale, Dynamic Gait Index, 6-Minute Walk Test, cardiovascular fitness (VO2 peak), Falls Efficacy Scale, and 5-day Step Activity Monitoring. RESULTS: Seven men and women with chronic ischemic stroke completed the 6-month intervention. The mean Berg Balance baseline score increased from 33.9+/-8.5 to 46+/-6.7 at 6 months (mean+/-SD; p=.006). Dynamic Gait Index increased from 13.7+/-3.0 to 19.0+/-3.5 (p=.01). Six-minute walk distance increased from 840+/-110 feet to 935+/-101 feet (p=0.02). VO2 peak increased from 15.3+/-4.1 mL/kg/min to 17.5+/-4.7 mL/kg/min (p=.03). There were no significant changes in falls efficacy or free-living ambulatory activity. CONCLUSION: A structured adaptive physical activity produces improvements in balance, gait, fitness, and ambulatory performance but not in falls efficacy or free-living daily step activity. Randomized studies are needed to determine the cardiovascular health and functional benefits of structured group physical activity programs and to develop behavioral interventions that promote increased free-living physical activity patterns.

A longitudinal study of sedentary behavior and overweight in adolescent girls.

The aim of this study is to examine sedentary and light activity in relation to overweight in adolescent girls. Adolescent girls were randomly recruited from 36 schools participating in the Trial of Activity for Adolescent Girls (TAAG). Assessments included age, ethnicity, socioeconomic status, and body composition estimated from weight, height, and triceps skinfold. Sedentary and light activity was measured for 6 days using accelerometry in 6th and in 8th grade among two randomly sampled cross-sections of girls. Sedentary activity increased from the 6th to 8th grade by 51.5 min/day. In the 8th grade, a significantly higher number of hours in sedentary activity for each of the 6-days of measurement were evident with higher tertiles of percent body fat (30-35%, >35% fat) (P < 0.05), but not across all increasing tertiles of BMI (5th to 85th, 85th to 95th, and >95th percentiles). The increase in sedentary activity was observed on weekdays, but not on weekends for percent body fat tertiles. In the cohort of girls measured in both 6th and 8th grades, the mean cross-sectional coefficient estimates were significant for percent body fat, but not BMI for sedentary and light activities. Adolescent girls from the 6th to 8th grade are shifting their time from light to more sedentary activity as measured by accelerometers. In addition, the increase in sedentary activity is not associated with an adverse effect on BMI or percent body fat. The eventual impact of this shift to a more sedentary lifestyle on body composition and other outcomes needs to be evaluated further.

Food-related behavior, physical activity, and dietary intake in First Nations - a population at high risk for diabetes.

OBJECTIVE: To describe determinants of diet-related behavior and physical activity in First Nations for development of culturally appropriate diabetes prevention programs. DESIGN. Cross-sectional 24-hour dietary recalls (n=129), random household risk factor surveys of primary food preparers/shoppers (n=133), and accelerometry (n=81) were assessed in First Nations adults. SETTING: Nine Anishinaabe (Ojibwe and Oji-Cree) First Nations in northwestern Ontario, Canada. RESULTS: Descriptive statistics (mean, SD, range) were calculated for all outcomes (dietary intake, psychosocial determinants of diabetes risk factors, dietary behaviors, physical activity, and body mass index, BMI) and t-tests were performed to examine differences in means between remote and semi-remote communities. Regression models adjusting for sociodemographic factors were also fit for the outcome measures. Respondents reported high-energy intake (2676 and 2060 kcal/day for men and women, respectively) and acquired higher fat/higher sugar/lower fiber foods up to 30 times more often than healthier alternatives. Over 80% of respondents were overweight or obese (BMI >25 kg/m(2)) with no significant difference between remote and semi-remote communities. Employment and having diabetes or impaired glucose tolerance were positively associated with BMI. Food intention scores were positively associated with healthy food acquisition scores. Younger respondents in semi-remote communities were more likely to have higher knowledge scores. Food intention scores were predicted by outcome expectations; outcome expectations by self-efficacy. CONCLUSIONS: Diabetes prevention programs for First Nations should focus on improving physical activity and dietary intake by targeting specific risk group needs. Food knowledge, self-efficacy, outcome expectations, and intention are important factors in understanding those needs.

An integrated multi-institutional diabetes prevention program improves knowledge and healthy food acquisition in northwestern Ontario First Nations.

This article presents the impact results of a feasibility study in Canada for prevention of risk factors for diabetes in seven northwestern Ontario First Nations. Baseline and follow-up data were collected before and after the 9-month intervention program in schools, stores, and communities that aimed to improve diet and increase physical activity among adults. Regression analyses indicate a significant change in knowledge among respondents in intervention communities (p < .019). There was also a significant increase in frequency of healthy food acquisition among respondents in the intervention communities (p < .003). There were no significant changes in physical activity or body mass index in either intervention or comparison groups. The multi-institutional approach demonstrated promising results in modifying selected risk factors for diabetes First Nations communities.

Patterns of objectively measured physical activity in the United States.

PURPOSE: We used latent class analysis (LCA) to assess patterns of physical activity among adults, using the 7 d of accelerometer data from the 2003-2004 NHANES. METHODS: For each participant, we determined the daily minutes of moderate-to-vigorous physical activity (MVPA), vigorous physical activity (VPA), and minutes of MVPA that occurred in bouts of 10 min. Participants were then categorized into patterns of activity, using LCA and adjusting for sociodemographic characteristics. RESULTS: For overall MVPA, five classes of physical activity were defined, including two least active classes, which averaged less than 25 min of MVPA per day and represented 78.7% of the total study population. The most active class averaged 134 min of MVPA per day and comprised 0.9% of the population. The results for bout minutes of MVPA were similar to the patterns produced for overall MVPA, with the exception of a "weekend warrior" class with moderate levels of physical activity Monday through Friday but with a much higher level of activity on the weekend, particularly on Sunday. This class represented 1.8% of the population. Only 1.4% of all days achieved 10 min or more of VPA, and in 91.1% of all days, participants accumulated less than 1 min of VPA. The LCA analysis of VPA did not produce stable results, because of the small number of participants registering any minutes of VPA. CONCLUSION: Our results indicate that a very large portion of the U.S. population may be classified into patterns of physical activity that represent low levels of MVPA throughout the week. The LCA analysis provided a novel approach for assessing patterns of objectively measured physical activity in epidemiologic studies.

Objectively assessed associations between physical activity and body composition in middle-school girls: the Trial of Activity for Adolescent Girls.

Declining levels of physical activity probably contribute to the increasing prevalence of overweight in US youth. In this study, the authors examined cross-sectional and longitudinal associations between physical activity and body composition in sixth- and eighth-grade girls. In 2003, girls were recruited from six US states as part of the Trial of Activity for Adolescent Girls. Physical activity was measured using 6 days of accelerometry, and percentage of body fat was calculated using an age- and ethnicity-specific prediction equation. Sixth-grade girls with an average of 12.8 minutes of moderate-to-vigorous physical activity (MVPA) per day (15th percentile) were 2.3 times (95% confidence interval: 1.52, 3.44) more likely to be overweight than girls with 34.7 minutes of MVPA per day (85th percentile), and their percent body fat was 2.64 percentage points greater (95% confidence interval: 1.79, 3.50). Longitudinal analyses showed that percent body fat increased 0.28 percentage points less in girls with a 6.2-minute increase in MVPA than in girls with a 4.5-minute decrease (85th and 15th percentiles of change). Associations between MVPA in sixth grade and incidence of overweight in eighth grade were not detected. More population-based research using objective physical activity and body composition measurements is needed to make evidence-based physical activity recommendations for US youth.

Weekend and weekday patterns of physical activity in overweight and normal-weight adolescent girls.

OBJECTIVE: To describe the patterns (specifically comparing weekdays and weekends classified by intensities) of physical activity (PA) measured by accelerometry in adolescent girls. RESEARCH METHODS AND PROCEDURES: Healthy sixth grade girls (n=1603), 11 to 12 years old, were randomly recruited from 36 schools participating in the Trial of Activity in Adolescent Girls. Age, ethnicity, socioeconomic status, weight, and height were taken. PA patterns were measured for 6 days using accelerometry. RESULTS: Adolescent girls spend most of their time in sedentary (52% to 57% of the day) and light activity (40% to 45% of the day) on weekdays and weekends. In all girls, total PA comprised 44.5% of the day (41.7% light, 2.2% moderate, and 0.7% vigorous) with sedentary activity comprising 55.4%. Moderate-to-vigorous PA (MVPA) was higher (p<0.001) on weekdays than weekends in all girls, but MVPA was lower in at-risk of overweight+overweight girls (p<0.001) on both weekdays and weekends compared with normal-weight girls. DISCUSSION: Adolescent girls are more active at moderate and vigorous intensities on weekdays than on weekends, and at-risk of overweight and those overweight spend less time engaging in MVPA than normal-weight girls.