Accelerometry cut points for physical activity in underserved African Americans

Background: Despite their increased use, no studies have examined the validity of Actical accelerometry cut points for moderate physical activity (PA) in underserved (low-income, high-crime), minority populations. The high rates of chronic disease and physical inactivity in these populations likely impact the measurement of PA. There is growing concern that traditionally defined cut points may be too high for older or inactive adults. The present study aimed to determine the self-selected pace associated with instructions to walk for exercise and the corresponding accelerometry estimates (e.g. Actical counts/minute) for underserved, African American adults. Method: Fifty one participants (61% women) had a mean age of 60.1 (SD=9.9) and a mean body mass index of 30.5 kg/m2 (SD=60). They performed one seated task, on standing task, and three walking tasks: strolling ; walking for exercise ; and walking in an emergency. Results: The average pace for strolling, walking for exercise, and walking in an emergency were 1.62 miles per hour (mph; SD=.51), 2.51 mph (SD=.53), and 2.86 mph (SD=.58), respectively. Regression analyses showed that the predicted counts/minute for a pace of 2.0 mph (which is used as the criterion for moderate exercise in this study) was 1075 counts/minute (SEM=73). Conclusions: The cut point associated with subjectively determined moderate PA is similar to those previously published for older adults and extends to the use of adjusted cut points to African American populations. These results indicate that accurate cut points can be obtained using this innovative methodology

Validity of the WHO cutoffs for biologically implausible values of weight, height, and BMI in children and adolescents in NHANES from 1999 through 2012

The WHO cutoffs to classify biologically implausible values (BIVs) for weight, height, and weight-for-height in children and adolescents are widely used in data cleaning

Results of the Active by Choice Today (ACT) Randomized Trial for Increasing Physical Activity in Low-Income and Minority Adolescents

Objective - This study reports the results of the Active by Choice Today (ACT) trial for increasing moderate-to-vigorous physical activity (MVPA) in low-income and minority adolescents. Design - The ACT program was a randomized controlled school-based trial testing the efficacy of a motivational plus behavioral skills intervention on increasing MVPA in underserved adolescents. Twenty-four middle schools were matched on school size, percentage minorities, percentage free or reduced lunch, and urban or rural setting before randomization. A total of 1,563 6th grade students (mean age, 11.3 years, 73% African American, 71% free or reduced lunch, 55% female) participated in either a 17-week (over one academic year) intervention or comparison after-school program. Main Outcome Measure - The primary outcome measure was MVPA based on 7-day accelerometry estimates at 2-weeks postintervention and an intermediate outcome was MVPA at midintervention. Results - At midintervention students in the intervention condition engaged in 4.87 greater minutes of MVPA per day (95% CI: 1.18 to 8.57) than control students. Students in intervention schools engaged in 9.11 min (95% CI: 5.73 to 12.48) more of MVPA per day than those in control schools during the program time periods; indicating a 27 min per week increase in MVPA. No significant effect of the ACT intervention was found outside of school times or for MVPA at 2-weeks postintervention. Conclusions - Motivational and behavioral skills programs are effective at increasing MVPA in low-income and minority adolescents during program hours, but further research is needed to address home barriers to youth MVPA

Relations Among Risk For Metabolic Syndrome, Social Ecological Factors, Nutrition, and Physical Activity In Underserved Youth

The high rate of obesity in youth contributes to the rising prevalence of metabolic syndrome and type 2 diabetes, particularly in underserved adolescents (low income, minorities) who show an increased risk for chronic disease. The present study integrated social cognitive theory and family systems theory within a bioecological framework to examine key social contextual influences on diet and physical activity (PA) in youth who are at high risk for chronic disease (diabetes, metabolic syndrome). Previous literature has supported the evaluation of social contextual variables, including parenting factors, and home and neighborhood influences, in understanding health behaviors. However, there is a dearth of literature on underserved populations, and little research examines these relations in adolescents at high risk for developing chronic diseases. The current study expanded on previous literature by examining the impact of individual factors including metabolic risk and self-efficacy, as well as family and environmental influences on diet and PA. Furthermore, the current study was novel in conducting exploratory analyses on metabolic risk for type 2 diabetes as a moderator of social contextual variables and health behaviors to better understand the onset of chronic disease. It was hypothesized that positive social contextual factors (e.g., fewer barriers, more support) would show positive relations with diet (i.e., fruit, vegetable, and reduced fat intake) and PA (light PA and moderate-to-vigorous PA) in minority and low-income adolescents. Social contextual variables included youth-reported relapse prevention self-efficacy, parent-reported parental limit-setting and monitoring, parental support, home PA resources, neighborhood supports for PA, and geographic information systems estimates of proximity to food markets and establishments. Moderation analyses with social-contextual variables and health behaviors (diet and PA) were explored with two directional hypotheses: a) that relations would be stronger in youth at higher risk such that they are more receptive to social contextual influences due to increased awareness, or b) that relations would be weaker such that further disease progression outweighs any potential social contextual benefits. Results of regression analyses showed no significant predictors of moderate-to-vigorous PA (F(9,191)=1.88, R2 = .08) but showed significant effects of parental (β = .16) and neighborhood support (β = .14) on light PA (F(9,191)=2.91, R2 = .12). Results also showed self-efficacy (β = -.27) was significantly associated with lower fat intake and limit-setting (β = .22) was significantly associated with higher fat intake. No significant effects were found for fruit and vegetable consumption (F(9,191)=2.21, R2 = .10). Exploratory results indicated that youth at higher metabolic risk showed weaker relations between positive social contextual variables and health behaviors. The current study emphasizes the importance of taking an ecological approach to understanding health behaviors in adolescents, particularly those at highest risk for developing chronic diseases including metabolic syndrome, type 2 diabetes, and cardiovascular disease later in life. Furthermore, results can be used to inform the development of more effective interventions to prevent the onset of chronic disease in underserved youth and more accurate early identification of those at greatest risk

Social Context, Intrinsic Motivation, and Physical Activity In Underserved Adolescents In the Act Trial: A Mediation Analysis

Previous research has shown that interventions to increase physical activity (PA) in adolescents, while statistically significant, have demonstrated only modest effects and have failed to identify mechanisms for change. Social Cognitive Theory (SCT) and Self-Determination Theory (SDT) identify social context and intrinsic motivation, respectively, as important factors to consider in understanding PA behavior. This study expands on previous research by examining intrinsic motivation as a mediator of the relationship between peer social support and moderate-to-vigorous PA (MVPA, measured by 7-day accelerometry) in underserved adolescents (low income, minorities). While SCT supports a relationship between peer social support and MVPA, SDT expands by suggesting the social contextual influences on behavior operate by increasing intrinsic motivation. In the current study, peer social support is hypothesized to positively effect intrinsic motivation (theoretically via positive social context) and, in turn, MVPA. Baseline data from the Active by Choice Today (ACT) Trial were analyzed using the product-as-coefficients methods of estimating a mediation relationship (n = 1421, mean age 11.3 years, 54% female, 72% African American, 71% reduced lunch). Adolescents self-reported peer social support and intrinsic motivation. Multiple imputations were used to handle missing data, and BMI and sex were covariates. Results showed steps for establishing mediation and a mediation effect (tested using the first order test; B = 1.63, se = 0.65, T (1420) = 2.53, p \u3c .05) were statistically significant. Secondary analyses examined sex differences using moderated mediation and found the mediation effect did not significantly differ for boys versus girls. Results of the current study are the first to demonstrate that intrinsic motivation mediates the relationship been peer support and MVPA in underserved adolescents. While more research is needed to better understand the social conditions that influence intrinsic motivation, results of the current study suggest that these factors may be important in future interventions in underserved populations

Temperament Moderates Cognitive Function at 15 Months

It is becoming increasingly clear that infants’ and toddlers’ temperament may play a central role in their cognitive and linguistic functioning. Research has found, for example, that at 21 months of age, children’s “attentional focus” moderates the extent that environmental distractions prevent them from learning novel words or solving nonlinguistic problems. The purpose of the present investigation was to explore the extent that dimensions of temperament moderate the performance of 15-month-olds on two typical nonlinguistic problemsolving tasks in the presence of environmental distractions. Forty-two 15-month olds visited the lab and were presented two tasks: “feed bear” and “make a rattle.” Infants were familiarized with the two sets of props initially, and then were presented models of desired action sequences. Half the children experienced a distraction during the feed bear task, the remaining were distracted during make a rattle. For each task, four dependent variables were scored: number of target actions performed, variety of target actions performed, longest chain of target actions performed, and number of pairs of actions performed in order. Temperament was measured via maternal report using the Early Child Behavior Questionnaire. Multivariate analyses revealed that children’s performance varied as a function of task [F(5, 24) = 5.42, p = .001]. The distractions also attenuated the effects of the model for both feed bear [univariate Fs(1, 40) = 4.21 to 9.22, ps = .047 to .018] and make a rattle [univariate Fs (1, 40) = 4.08 to 6.08, ps = .050 to .018]. Interactions of these effects with temperament were many, but complex. For example, low intensity pleasure moderated distracter effects, but only for feed bear [Fs(1, 27) = 5.19 to 9.73, ps = .031 to .004]. In other analyses, toddlers low in perceptual sensitivity benefited more from the model than did children high on that dimension [F’s(1, 28) = 3.71 to 6.67, p’s = .064 to .015)]. A number of additional temperament related findings also obtained. There is considerable reason to continue explorations into potential roles that temperament may play in infants’ cognitive and language development. Results from the present study extend previous findings to the 15-month age period, which, to our knowledge, has not been investigated in previous research. The present results also suggest that roles played by temperament may be exceptionally complex, and highlight the multifaceted internal and external experiences through which children must navigate to become competent thinkers and communicators in an adult world

Temperament Moderates Novel Word Learning at 15 Months

Researchers have been reporting temperament-language correlations in infants for 10 years. However, in order to identify directions of effects between temperament and language, methodologies besides correlations need to be developed. The “competition attention paradigm” is an effort to sidestep some of the direction-of-effect issues by asking infants to learn novel words in the context of environmental distractions designed to tap into children’s temperaments. The purpose of the present study was to explore whether environmental distracters would differentially impact 15-month-olds’ novel wordlearning as a function of children’s temperamental profiles. Twenty-eight 15-month-olds were asked to learn 4 novel words. Novel word learning consisted of initially familiarizing children with two novel objects, and then mapping a novel label to only one of the novel objects five times. Novel word comprehension was tested by asking children to select the newly-labeled object from the pair of novel objects across 4 test trials. A remotely-controlled mechanical spider competed for children’s attention during object familiarization on two of the words. Half the children were distracted on the first two words, half were distracted on the last two. Temperament was assessed via parental reporting using the Early Child Behavior Questionnaire. The environmental distractions did not impact children’s word-learning directly. However, order of distraction presentation did [F(1, 23) = 7.16, p = .014], such that children who were distracted on the first two words performed higher overall than children who were distracted on the last two. Results involving temperament were complex, yielding many significant interaction effects with factors impacting children’s word-learning. For example, children high in fear demonstrated better word-learning in the absence of the spider than in its presence, whereas the spider had no effect on low-fear children, but only when learning the first word in the pair [F(1, 23) = 5.20, p = .032]. Other temperament factors found to impact novel word-learning included attentional focus, cuddliness, impulsivity, frustration, and high intensity pleasure. The results of the present investigation contribute to a growing body of research linking temperament to word learning. The competition attention paradigm suggest ways through which word learning may be impacted by dimensions of temperament. Although not presentable here due to space limitations, the pattern of results also points to attentional focus as playing a central moderating role over other dimensions of temperament. Finally, the present results are the first to link temperament to language acquisition at 15 months