Technical report: an online international weight control registry to inform precision approaches to healthy weight management.

BACKGROUND: Personalizing approaches to prevention and treatment of obesity will be a crucial aspect of precision health initiatives. However, in considering individual susceptibility to obesity, much remains to be learned about how to support healthy weight management in different population subgroups, environments and geographical locations. SUBJECTS/METHODS: The International Weight Control Registry (IWCR) has been launched to facilitate a deeper and broader understanding of the spectrum of factors contributing to success and challenges in weight loss and weight loss maintenance in individuals and across population groups. The IWCR registry aims to recruit, enroll and follow a diverse cohort of adults with varying rates of success in weight management. Data collection methods include questionnaires of demographic variables, weight history, and behavioral, cultural, economic, psychological, and environmental domains. A subset of participants will provide objective measures of physical activity, weight, and body composition along with detailed reports of dietary intake. Lastly, participants will be able to provide qualitative information in an unstructured format on additional topics they feel are relevant, and environmental data will be obtained from public sources based on participant zip code. CONCLUSIONS: The IWCR will be a resource for researchers to inform improvements in interventions for weight loss and weight loss maintenance in different countries, and to examine environmental and policy-level factors that affect weight management in different population groups. This large scale, multi-level approach aims to inform efforts to reduce the prevalence of obesity worldwide and its associated comorbidities and economic impacts. TRIAL REGISTRATION: NCT04907396 (clinicaltrials.gov) sponsor SB Roberts; Tufts University IRB #13075.

Similar weight loss and maintenance in African American and White women in the Improving Weight Loss (ImWeL) trial.

Objective: African Americans (AA) are often underrepresented and tend to lose less weight than White participants during the intensive phase of behavioral obesity treatment. Some evidence suggests that AA women experience better maintenance of lost weight than White women, however, additional research on the efficacy of extended care programs (i.e. continued contacts to support the maintenance of lost weight) is necessary to better understand these differences.Methods: The influence of race on initial weight loss, the likelihood of achieving ≥5% weight reduction (i.e. extended care eligibility), the maintenance of lost weight and extended care program efficacy was examined in 269 AA and White women (62.1% AA) participating in a 16-month group-based weight management program. Participants achieving ≥5% weight reduction during the intensive phase (16 weekly sessions) were randomized to a clustered campaign extended care program (12 sessions delivered in three, 4-week clusters) or self-directed control.Results: In adjusted models, race was not associated with initial weight loss (p = 0.22) or the likelihood of achieving extended care eligibility (odds ratio 0.64, 95% CI [0.29, 1.38]). AA and White women lost -7.13 ± 0.39 kg and -7.62 ± 0.43 kg, respectively, during initial treatment. There were no significant differences in weight regain between AA and White women (p = 0.64) after adjusting for covariates. Clustered campaign program participants (AA: -6.74 ± 0.99 kg, White: -6.89 ± 1.10 kg) regained less weight than control (AA: -5.15 ± 0.99 kg, White: -4.37 ± 1.04 kg), equating to a 2.12 kg (p = 0.03) between-group difference after covariate adjustments.Conclusions: Weight changes and extended care eligibility were comparable among all participants. The clustered campaign program was efficacious for AA and White women. The high representation and retention of AA participants may have contributed to these findings.

Weight Gain and Blood Pressure in Toddlers Born Very Preterm.

BACKGROUND: Preterm birth is a risk factor for elevated blood pressure in childhood and the development of hypertension and cardiometabolic disease in adulthood; however, mechanisms for the development of both are poorly understood. Rapid weight gain early in childhood may serve as a driver directly and indirectly through cortisol levels found to be elevated in early childhood in individuals born preterm. OBJECTIVES: The objective of this pilot study was to examine the effect sizes of the relationships between weight gain and blood pressure in toddlers born very preterm. A secondary aim was to note any mediating effect of cortisol on the relationships between weight gain and blood pressure. METHODS: A cross-sectional design with a convenience sample of 36 toddlers who were born very preterm was used to examine the relationships between postnatal weight gain, cortisol, and blood pressure at follow-up. RESULTS: Many of the participants experienced rapid weight gain in the first 12 months of life. Mean systolic and diastolic readings were 94 and 56.6, respectively. Diastolic blood pressure readings were obtained from 23 participants, and the majority were elevated. Weight gain was associated with diastolic blood pressure with a medium effect size. A mediating role with cortisol was not supported. DISCUSSION: Although findings need to be validated in a larger sample, the blood pressure elevations in this sample were alarming. If readings continue to amplify as these children age, the fact that elevations are already present during the toddler period could indicate more significant cardiovascular disease in adulthood for this population. Rapid weight gain in early life may be a driver for elevated blood pressure even during early childhood in individuals born preterm.

Infant Feeding Practices and Weight Gain in Toddlers Born Very Preterm: A Pilot Study.

PURPOSE: Long-term consequences of prematurity are a public health concern. A pattern of slow initial weight gain followed by a period of rapid weight gain has been associated with poor cardiometabolic health outcomes. The purpose of this study was to examine the relationships between infant feeding practices and weight gain in a sample of 18-to-24-month olds corrected age born very preterm. DESIGN AND METHODS: A cross-sectional design was used to examine the relationships between infant feeding practices and weight gain. Estimates of effect sizes and model fit estimates were the primary parameters of interest. RESULTS: Most of the participants received human milk after birth, but most had transitioned to formula before three months. Slightly less than half received complementary foods prior to four months corrected age. Gains in weight and head circumference were rapid after discharge from the neonatal intensive care unit, while gains in length lagged behind. Infant feeding practices did not have a clinically meaningful effect on weight gain. CONCLUSIONS: While the initiation of human milk feedings was encouraging, the duration fell short of recommendations. Practices such as the early introduction of complementary feedings and the addition of rice cereal to the bottle are troubling. Additionally, the rapid increase in weight gain may have a negative impact on future cardiometabolic health. PRACTICE IMPLICATIONS: Clinical recommendations include ensuring support for the use of human milk before and after hospital discharge, close monitoring of physical growth, and ensuring adherence to the guidelines for the introduction of complementary foods.

Relationship between social support and body mass index among overweight and obese African American women in the rural deep South, 2011-2013.

INTRODUCTION: African American women in the Deep South of the United States are disproportionately obese, a condition strongly influenced by their social environment. The objective of this study was to characterize the prevalence of social support from family and friends for healthy eating and exercise in rural communities. METHODS: This study is an analysis of a subgroup (N = 195) of overweight and obese African American women from a larger ongoing weight loss trial (N = 409) in rural communities of the Alabama Black Belt and Mississippi Delta. The Social Support and Eating Habits Survey and Social Support and Exercise Survey were used to measure support from family and friends for healthy eating and exercise, respectively. Linear regression was conducted to determine the association between social support factors and body mass index (BMI). RESULTS: Concurrently prevalent in our sample were encouraging support for healthy eating (family, median,14.0; range, 5.0-25.0; friends, median, 13.0; range 5.0-25.0) and discouraging support for healthy eating (family, median, 12.0; range, 5.0-25.0; friends, median, 11.0; range, 5.0-25.0). Median scores for support for exercise received in the form of participation from family and friends were 24.0 (range 10.0-48.0) and 24.0 (range 10.0-50.0), respectively. The median score for support for exercise in the form of rewards and punishment from family was 3.0 (range, 3.0-11.0). Social support factors were not associated with BMI. CONCLUSION: Overweight and obese African American women in the rural Deep South experience minimal social support from family and friends for healthy eating and exercise. Given the evidence that social support promotes healthy behaviors, additional research on ways to increase support from family and friends is warranted.

Predictors of moderate-to-vigorous physical activity (MVPA) in African American young adolescents.

BACKGROUND: African American adolescents residing in the South are at increased risk for obesity and physical inactivity, yet our understanding of potential influences is limited. PURPOSE: Using an ecological framework, this study explored multilevel predictors (individual, family, home, and neighborhood environment) of moderate-to-vigorous physical activity (MVPA) among 116 African American adolescents (ages 12-16). METHODS: Adolescents and their parents completed self-report surveys for hypothesized predictors. Youth physical activity was measured using accelerometry. RESULTS: In multiple regression models, decreased daily MVPA was associated with female sex (ß = -24.27, p < 0.0001). Family social support (ß = 1.07, p = 0.004) and adolescent self efficacy for PA (ß = 6.89, p = 0.054) were positively associated with daily MVPA. CONCLUSIONS: Adolescent demographics along with family social support and self-efficacy influence younger African American adolescent physical activity. Further exploration of the complex interaction of multiple levels of influence is needed to develop appropriate interventions for this vulnerable group.

Harvest for health gardening intervention feasibility study in cancer survivors.

BACKGROUND: Cancer survivors are at increased risk for second malignancies, cardiovascular disease, diabetes, and functional decline. Evidence suggests that a healthful diet and physical activity may reduce the risk of chronic disease and improve health in this population. METHODS: We conducted a feasibility study to evaluate a vegetable gardening intervention that paired 12 adult and child cancer survivors with Master Gardeners to explore effects on fruit and vegetable intake, physical activity, quality-of-life, and physical function. Throughout the year-long study period, the survivor-Master Gardener dyads worked together to plan/plant three gardens, harvest/rotate plantings, and troubleshoot/correct problems. Data on diet, physical activity, and quality-of-life were collected via surveys; anthropometrics and physical function were objectively measured. Acceptability of the intervention was assessed with a structured debriefing survey. RESULTS: The gardening intervention was feasible (robust enrollment; minimal attrition) and well-received by cancer survivors and Master Gardeners. Improvement in three of four objective measures of strength, agility, and endurance was observed in 90% of survivors, with the following change scores [median (interquartile range)] noted between baseline and one-year follow-up: hand grip test [+ 4.8 (3.0, 6.7) kg], 2.44 meter Get-Up-and-Go [+ 1.0 (+ 1.8, + 0.2) seconds], 30-second chair stand [+ 3.0 (+ 1.0, 5.0) stands], and six-minute walk [+ 11.6 (6.1, 48.8) meters]. Increases of ≥ 1 fruit and vegetable serving/day and ≥ 30 minutes/week of physical activity were observed in 40% and 60%, respectively. CONCLUSION: These preliminary results support the feasibility and acceptability of a mentored gardening intervention and suggest that it may offer a novel and promising strategy to improve fruit and vegetable consumption, physical activity, and physical function in cancer survivors. A larger randomized controlled trial is needed to confirm our results.

The associations of perceived neighborhood disorder and physical activity with obesity among African American adolescents.

BACKGROUND: According to recent research studies, the built and socioeconomic contexts of neighborhoods are associated with African American adolescents' participation in physical activity and obesity status. However, few research efforts have been devoted to understand how African American adolescents' perceptions of their neighborhood environments may affect physical activity behaviors and obesity status. The objective of the current study was to use a perceived neighborhood disorder conceptual framework to examine whether physical activity mediated the relationship between perceived neighborhood disorder and obesity status among African American adolescents. METHODS: The data were obtained from a cross-sectional study that examined social and cultural barriers and facilitators of physical activity among African American adolescents. The study included a sample of 101 African American adolescents age 12 to 16 years and their parents who were recruited from the Birmingham, Alabama metropolitan area. The primary outcome measure was obesity status which was classified using the International Obesity Task Force cut off points. Moderate-to-vigorous physical activity was assessed via accelerometry. Perceived neighborhood disorder was assessed using the Perceived Neighborhood Disorder Scale. Mediation models were used to examine whether the relationship between neighborhood disorder and obesity status was mediated by physical activity. RESULTS: Perceived neighborhood disorder was significantly and positively related to obesity status and moderate-to-vigorous physical activity was inversely associated with obesity status. However, there was no evidence to support a significant mediating effect of moderate-to-vigorous physical activity on the relationship between neighborhood disorder and obesity status. CONCLUSION: Future studies should longitudinally assess perceived neighborhood disorder characteristics and childhood adiposity to examine the timing, extent, and the mechanisms by which perceived neighborhood disorder characteristics increase the risk of obesity.

Social Environments and Physical Activity Among Active Black Women.

PURPOSE: To explore the social context of physical activity (PA) among active Black women, we examine the patterns of PA engagement and the benefits of social support in PA maintenance. DESIGN: A cross-sectional study design and descriptive phenomenological approach were used to examine social support and lived experiences of active Black women. SETTING: The study setting was an online survey of active Black women, ages 21 to 71 years who were recruited from across the United States. PARTICIPANTS: This secondary data analysis was conducted among a sample of 187 active Black women who maintained PA for ≥6 months. The mean age was 41 ± 12.3 years, 83.4% completed some college, 37.7% were married, and 30.0% had children. MEASURES: Participants self-reported 'with whom' they engaged in PA and provided qualitative responses about their strategies for PA maintenance. Descriptive statistics were used to examine between-group differences among demographic characteristics and PA variables by category of PA engagement using SAS 9.4. Descriptive phenomenology was used to explore social support themes across and within categories of PA engagement. RESULTS: On average, the active Black women in this study reported engaging in 57.0 ± 18.9 minutes of moderate intensity leisure-time PA per session. Most engaged in PA alone (n = 87), with a group (n = 72), or with another individual (n = 28). Social context themes within categories included: alone - self-management, groups - motivation and accountability, family - values health, and friends - shared interests in PA. Subthemes across social context categories included: who? - people, what and how? - types of social support, and where? - place of social support. CONCLUSIONS: Our findings suggest that some Black women may need added social support from others beyond family and friends, while other Black women may prefer additional self-management skills. Nonetheless, this study provides data for developing hypotheses about the mechanisms by which social context may facilitate PA maintenance among Black women. Therefore, intervention studies targeting PA maintenance among Black women should include an in-depth query of social support needs.

Texting Older Sisters to Step to Manage Obesity in Older Black Women: A Feasibility Study.

INTRODUCTION: Black women are disproportionately classified as overweight or obese and physically inactive. Social support and culturally relevant and age-appropriate physical active interventions are needed to reduce inactivity and to prevent weight gain among this group. Mobile-health text messages have shown to be an acceptable, feasible and interactive way to promote physical activity among older Black women. STUDY DESIGN: This feasibility, 12-week RCT, deployed between August 2020 and December 2020, aimed to determine the feasibility and effectiveness of a mobile health intervention that focused on increasing physical activity behaviors among community-dwelling, older Black women who were age ≥60 years and classified with overweight or obesity. SETTING/PARTICIPANTS: Community-dwelling, older Black women. INTERVENTION: The intervention group received physical activity promotion text messages daily, whereas the control group received 1 neutral message related to general health information weekly. MEASURES: At baseline and post intervention assessments, researchers obtained HbA1c levels, weight, BMI, waist circumference, and questionnaires related to physical activity. Post-intervention satisfaction was also collected through a survey. RESULTS: The intervention group had an average increase of approximately 700 steps per day more than the control group, lost more waist circumference inches (2.2) than the controls, and averaged more pound loss (2.5) than controls. The control group had a greater HbA1c reduction, whereas the intervention group remained stable. The text messages were 100% readable, and 95% of the women stated the study was motivational. Overall, 12% of participants suggested that future studies should include more in-person social support, and 8.3% said that daily text messages were too much. CONCLUSIONS: Findings suggest that a mobile health physical activity intervention that uses self-monitoring techniques in conjunction with motivational cues, is an acceptable delivery method and a promising strategy to increase physical activity behaviors among this population, which is feasible, potentially efficacious, and low cost. TRIAL REGISTRATION: NCT04114071.

Racial differences in growth rates and body composition of infants born preterm.

OBJECTIVE: To evaluate racial disparities in weight gain velocity and body composition among preterm infants. STUDY DESIGN: This observational study analyzed race differences in fat-free mass (FFM), fat mass (FM), percent body fat (%BF), and weight gain at discharge of infants born at 25-32 weeks of gestation. RESULTS: No racial differences in FFM, FM and %BF measurements were found between black and white preterm infants after adjusting for birth weight, gestational age, and the presence/absence of breastfeeding (n = 143). Black infants born preterm had lower birthweights and higher weight gain from birth to discharge in unadjusted and adjusted models (13 ± 3 vs. 11 ± 3 g/kg/day; <0.001). CONCLUSION: Black infants had higher weight gain from birth to discharge, but comparable body composition measurements at discharge. More research is needed to understand contributing factors and long-term implications of this finding.

Measuring parental support for children's physical activity in white and African American parents: the Activity Support Scale for Multiple Groups (ACTS-MG).

OBJECTIVES: The Activity Support Scale (ACTS) was expanded for use with African American families. Its factorial invariance and internal reliability were examined for non-Hispanic white and African American parents. METHODS: The ACTS was modified to improve its applicability to African American families based on information from five focus groups with 27 African American parents of elementary school-aged children. Between 2006 and 2008, the revised scale was administered to 119 African American and 117 non-Hispanic white parents in northeastern NY and Alabama. Its factorial invariance across race/ethnicity and internal consistency were examined. RESULTS: Factor analysis of the revised scale, the Activity Support Scale for Multiple Groups (ACTS-MG), identified four parenting factors in white and African American parents including logistic support, modeling, use of community resources to promote physical activity (PA), and restriction of sedentary behaviors. Results supported the scale's internal reliability and factorial invariance across race/ethnicity. CONCLUSION: The ACTS-MG is appropriate for use with non-Hispanic white and African American families and will enable the extension of current research with white families to the examination of strategies supporting PA in African American families. Additional psychometric work with the ACTS-MG is encouraged.

Validity of self-reported leisure-time sedentary behavior in adolescents.

BACKGROUND: To evaluate the concordance between leisure-time sedentary behavior in adolescents assessed by an activity-based questionnaire and accelerometry. A convenience sample of 128 girls and 73 boys, 11-15 years of age (12.6 ± 1.1 years) from six states across the United States examined as part of the feasibility studies for the Trial of Activity in Adolescent Girls (TAAG). Three days of self-reported time spent watching TV/videos, using computers, playing video/computer games, and talking on the phone was assessed using a modified version of the Self-Administered Physical Activity Checklist (SAPAC). Criterion measure of sedentary behavior was via accelerometry over three days using a cut point of < 50 counts · 30 sec⁻¹ epoch. Comparisons between sedentary behavior by the two instruments were made. RESULTS: Adolescents generally underestimated minutes of sedentary behavior compared to accelerometry-measured minutes. The overall correlation between minutes of sedentary behavior by self-report and accelerometry was weak (Spearman r = 0.14; 95% CI 0.05, 0.23). Adjustment of sedentary minutes of behavior for total minutes assessed using either percentages or the residuals method tended to increase correlations slightly. However, regression analyses showed no significant association between self-reported sedentary behavior and minutes of sedentary behavior captured via accelerometry. DISCUSSION: These findings suggest that the modified 3-day Self-Administered Physical Activity Checklist is not a reliable method for assessing sedentary behavior. It is recommended that until validation studies for self-report instruments of sedentary behavior demonstrate validity, objective measures should be used.

Attitudes and beliefs associated with leisure-time physical activity among African American adults.

OBJECTIVE: More than 60% of African American adults do not meet recommendations for moderate physical activity. We sought to discover the extent to which health attitudes and beliefs are associated with leisure-time physical activity in this population. DESIGN: Cross-sectional study. SETTING: African American adults were asked about their health attitudes and beliefs during a national survey. PARTICIPANTS: Participants were 807 African American men and women aged 18 years and older. Random-digit dialing was employed, sampling telephone numbers by geographical region, area code, and population size. MAIN OUTCOME MEASURES: Participants were asked six health belief questions on the importance of exercise and body weight in health. Logistic regression was used to determine which of these factors were associated with physical activity participation. RESULTS: The percent of respondents participating in some form of physical activity during the past month was 87.1% in men and 82.9% in women. Factors associated with previous month physical activity in men were perceived personal importance of exercise (P < .001) and necessity of exercise for health (P = .018). In women, perceived personal importance of exercise (P < .001), necessity of exercise for health (P = .006), and having enough activity space (P = .017) were associated with physical activity participation. CONCLUSION: Though the direction of causation is unknown, having the attitude that it is important to exercise or be physically active for health predicts physical activity participation in both African American men and women. Creating a sense of importance of physical activity to relieve stress and foster good health may stimulate physical activity participation in African American adults.

SBM Mid-Career Leadership Institute.

My purpose for participating in the 2017 Society for Behavior Medicine (SBM) Leadership Institute was to redefine my career goals in an effort to do more work that mattered. I felt overwhelmed by the numerous tasks as a mid-level researcher, including leadership roles outside of my university to fill a desire to pursue activities that were purposeful but not valued by the academy. For example, I served on the Board of Girls on the Run (GOTR) where I was chair, leading a team of about 12 board members to provide a running-based life skills program for girls in Grades 3-5. After stepping down from the Board, I chose to develop a partnership between GOTR and the University of Alabama at Birmingham's Center for Exercise Medicine (UCEM) that would provide an opportunity for me to lead an outreach effort extending the GOTR program into Birmingham City Schools. The goal was not only to reach more girls from disadvantaged backgrounds but also to also reach their family members. We used survey results to assess parent/family preferences for receiving physical activity training resources to be able to support their girls at the end-of-the program 5K celebration. The resources were made available via the UCEM website and a link was sent by GOTR to all families of participants in the program. Overall, the partnership allowed us to reach more girls and their families and I know that the SBM Leadership program contributed to my delegation and organizational skills coupled with coaching to reveal my strengths and blind spots.

Association of Food Access, Recreational Opportunities, and Natural Amenities with Engagement in the Veterans MOVE! Weight Management Program.

OBJECTIVE: The aim of this study was to examine the association of county-level food access, recreational opportunities, and natural amenities with participant engagement in a weight management program. METHODS: In this cohort study, participants in the Veterans Health Administration MOVE! weight management program between October 1, 2007, and September 30, 2013, were observed for 12 months after enrollment. Engagement was measured as the number of program visits per year at 12 months. Cross-sectional analysis and spatial regression were used to examine county characteristics associated with greater participant engagement at 12 months. RESULTS: A total of 321,624 participants in 2,708 counties were included. Greater engagement was associated with older age, female sex, white race, being married, and being retired. After accounting for similarities between nearby communities, engagement at 12 months was 3.1 visits higher for each additional farmers' market per 1,000 population (P = 0.01). Engagement was highest for participants living in counties with the most natural amenities (P < 0.001). Recreational opportunities had only a small effect on engagement in the program (ß = 0.02 visits at 12 months; P = 0.002). CONCLUSIONS: Consideration of a participant's county characteristics in addition to other known demographics and program factors may help to explain variation in engagement in weight management programs.

Body image and dissatisfaction among rural Deep South African American women in a weight loss intervention.

Body image perception may impact health-promoting behaviors as well as knowledge regarding health risks associated with obesity. Our cross-sectional analysis evaluated body image and its association with body mass index among overweight and obese treatment-seeking African American women (N = 409). Differences between current and desired body image were captured using the Pulvers scale. Results indicated the presence of body image dissatisfaction among participants (median = 2.00, interquartile range: 2.00-3.00), with greater dissatisfaction observed at higher categories of body mass index. Additionally, receiver operating curves demonstrated the ability of the Pulvers scale to correctly identify participants classified by body mass index. Further research is needed to identify factors that influence body image perception.

A Systematic Scoping Review of Surgically Manipulated Adipose Tissue and the Regulation of Energetics and Body Fat in Animals.

OBJECTIVE: Surgical manipulations of adipose tissue by removal, or partial lipectomy, have demonstrated body fat compensation and recovered body weight, suggesting that the body is able to resist changes to body composition. However, the mechanisms underlying these observations are not well understood. The purpose of this scoping review is to provide an update on what is currently known about the regulation of energetics and body fat after surgical manipulations of adipose tissue in small mammals. METHODS: PubMed and Scopus were searched to identify 64 eligible studies. Outcome measures included body fat, body weight, food intake, and circulating biomarkers. RESULTS: Surgeries performed included lipectomy (72%) or transplantation (12%) in mice (35%), rats (35%), and other small mammals. Findings suggested that lipectomy did not have consistent long-term effects on reducing body weight and fat because regain occurred within 12 to 14 weeks post surgery. Hence, biological feedback mechanisms act to resist long-term changes of body weight or fat. Furthermore, whether this weight and fat regain occurred because of "passive" and "active" regulation under the "set point" or "settling point" theories cannot fully be discerned because of limitations in study designs and data collected. CONCLUSIONS: The regulation of energetics and body fat are complex and dynamic processes that require further studies of the interplay of genetic, physiological, and behavioral factors.

Positive Outliers Among African American Women and the Factors Associated with Long-Term Physical Activity Maintenance.

Studying positive outliers, individuals who have achieved success with long-term (> 6-month) physical activity (PA) engagement, may be an important approach for understanding strategies for improving leisure-time PA maintenance among African American (AA) women. This cross-sectional, mixed-methods study (1) examined the personal characteristics, PA patterns, and behavioral practices of positive outliers among AA women and (2) compared characteristics of those who maintain PA at recommended levels (HIGH, ≥ 150 min/week > 6 months) with those who maintain low PA volumes (LOW, < 150 min/week > 6 months). A large sample of positive outliers completed this study (n = 290), and most became physically active on their own (76.2%). These AA women were committed to maintaining an active lifestyle, accumulated 249.7 ± 105.8 min of PA/week, and engaged in a variety of activities. Their behavioral practices included scheduling PA during the week (85.9%), goal-setting (82.4%), engaging in PA with others (55.9%), self-monitoring (78.3%), and having a backup plan for missed sessions (54.8%). HIGH maintainers (84.9%) made up most of the sample, and these women were characteristically similar to LOW maintainers with few differences. HIGH maintainers have been active longer, achieved higher commitment scores, and engaged in PA at a higher frequency, duration, and intensity, resulting in higher weekly PA volume compared to LOW maintainers (273.8 ± 96.1 vs. 114.4 ± 24.3 min per week, p ≤ 0.001). Our findings identify factors that may be important for successful PA maintenance among AA women and may help to inform the development of effective behavioral interventions to promote sustained, long-term PA engagement in this population.

Illustration of Measurement Error Models for Reducing Bias in Nutrition and Obesity Research Using 2-D Body Composition Data.

OBJECTIVE: This study aimed to illustrate the use and value of measurement error models for reducing bias when evaluating associations between body fat and having type 2 diabetes (T2D) or being physically active. METHODS: Logistic regression models were used to evaluate T2D and physical activity among adults aged 19 to 80 years from the Photobody Study (n = 558). Self-reported T2D and physical activity were categorized as "yes" or "no." Body fat measured by two-dimensional photographs was adjusted for bias using dual-energy x-ray absorptiometry scans as a reference. Three approaches were applied: regression calibration (RC), simulation extrapolation (SIMEX), and multiple imputation (MI). RESULTS: Unadjusted two-dimensional measures of body fat had upward biases of 30% and 233% for physical activity and T2D, respectively. For the physical activity model, RC-adjusted values had a 13% upward bias, whereas MI and SIMEX decreased the bias to 9% and 91%, respectively. For the T2D model, MI reduced the bias to 0%, whereas RC and SIMEX increased the upward bias to > 300%. CONCLUSIONS: Of three statistical approaches to reducing bias due to measurement errors, MI performed best in comparison to RC and SIMEX. Measurement error methods can improve the reliability of analyses that look for relations between body fat measures and health outcomes.