Compounding effects of stress on diet, physical activity, and wellbeing among African American parents: a qualitative study to inform the LEADS health promotion trial.

The purpose of the study was to conduct in-depth qualitative interviews to understand the lived experiences of African American parents of overweight adolescents who had previously participated in a family-based weight loss program and to utilize these insights to inform the essential elements of the LEADS trial, an integrated resilience stress management and health promotion intervention. Participants (N = 30) were African American parents and/or caregivers (96.7% female; Mage = 49.73, SD = 10.88; MBMI = 37.63, SD = 8.21) of adolescents with overweight and/or obesity. Interviews were transcribed and coded using inductive and deductive approaches for themes by two independent coders. Inter-rater reliability was acceptable (r = 0.70-0.80) and discrepancies were resolved to 100% agreement. Prominent stress themes included caregiver responsibilities, work, interpersonal family conflict, and physical and emotional consequences of chronic stress. Participants also noted decreases in physical activity and poor food choices due to stress. Coping mechanisms included prayer/meditation, church social support, and talking with family/partner. Results highlight the importance of mitigating stress among African American parents through stress management and cultural/familial resilience approaches to increase the likelihood of engagement in behavioral strategies in health promotion programs. Future studies should assess the utility of incorporating stress management components and health promotion techniques to improve health outcomes among African American families.

The mediating effects of motivation on the relations between occupational stress and physical activity among underresourced afterschool program staff.

OBJECTIVE: Guided by Self-Determination Theory, this study aimed to examine the potential mediating effects of autonomous and controlled motivations on physical activity (PA) experiences of afterschool program (ASP) staff with occupational stress. METHOD: A total of 58 ASP staff provided full data. Staff occupational stress and self-determination motivations for PA were assessed. Participants' daily moderate-to-vigorous physical activity (MVPA) was measured using accelerometer wear. A path analysis was used to address the research purpose. RESULTS: Occupational stress negatively and indirectly predicted daily MVPA which was mediated by controlled motivation (ß = - 4.15, p <.05). Autonomous motivation directly and positively predicted daily MVPA across all types and levels of ASP staff occupational stress (ß = 9.93, p =.01). CONCLUSIONS: Autonomous motivation is a powerful predictor of staff PA levels despite the degree to which they experience stress. In contrast, controlled motivations are more vulnerable to occupational stress, and can lead to lower MVPA. TRIAL REGISTRATION: Connect Through PLAY: A Staff-based Physical Activity Intervention for Middle School Youth (Connect). https://clinicaltrials.gov/ct2/show/NCT03732144 . Registered 11/06/2018. REGISTRATION NUMBER: NCT03732144.

Changing trajectory of daily physical activity levels among at-risk adolescents: influences of motivational mechanisms.

BACKGROUND: Guided by Self-Determination Theory (SDT), the purpose of this study was to determine changes in the 16-week moderate-to-vigorous physical activity (MVPA) trajectory of underserved adolescents who participated in the Connect through PLAY afterschool program intervention and the effects of changes in participating adolescents' intrinsic and autonomous extrinsic motivations on their MVPA trajectory over the 16-week intervention. METHODS: A subsample of 113 adolescents (56.64% female; 61.06% African American; average age = 11.29) provided complete data throughout the 16-week intervention were examined. Adolescents' objective daily MVPA was measured using 7- day accelerometer data. Changes in adolescents' intrinsic motivation and autonomous extrinsic motivation were assessed using subscales from the Intrinsic Motivation Inventory [1] and the Treatment Self-Regulation Questionnaire [2] respectively. A hierarchical linear model was built and tested to address the research aims. RESULTS: The results of hierarchical linear models showed that, on average, youth daily MVPA increased 6.36 minutes in each 8-week period. Intrinsic motivation change, but not autonomous extrinsic motivation, was a positive and significant level-2 predictor of daily MVPA changes. CONCLUSION: The findings provide significant evidence suggesting a benefit of integrating SDT-based approaches and further suggest that nurturing intrinsic motivation can be an effective approach to supporting youth daily MVPA in under-resourced afterschool programs. TRIAL REGISTRATION: Connect Through PLAY: A Staff-based Physical Activity Intervention for Middle School Youth (Connect). https://clinicaltrials.gov/ct2/show/NCT03732144 . Registered November 6th, 2018.

The influence of social support, social affiliation and intrinsic motivation for increasing underserved youth's physical activity: A social climate-based intervention study.

The purpose of this study was to investigate the influences of intrinsic motivation, social affiliation orientations and reciprocal social support for physical activity (PA) on underserved youths' afterschool period moderate-to-vigorous (MVPA) changing trajectories across the 16-week Connect through PLAY intervention, a social-motivational climate intervention. A total of 113 youth (61.06% African American, 56.64% girls) provided full data. Youths' intrinsic motivation, social affiliation orientations and social support were measured by youth responses to a set of surveys at baseline and post-intervention. Youths' afterschool period MVPA was measured using data from 7-day ActiGraph accelerometer wear at baseline, midpoint and post-intervention. Hierarchical linear modelling analysis found that youth daily afterschool period (3pm-6pm) MVPA increased, on average, 37.94 min across the 16-week intervention. Increases in intrinsic motivation, social affiliation orientations and social support were positive predictors of youth afterschool MVPA changing trajectory. The findings clarify the contributions that a social-motivational climate intervention can have on youth afterschool period MVPA through increasing youth intrinsic motivation, social affiliation and reciprocal social support.

An overview of the Together Everyone Achieves More Physical Activity (TEAM-PA) trial to increase physical activity among African American women.

BACKGROUND: The Together Everyone Achieves More Physical Activity (TEAM-PA) trial is a randomized controlled trial testing the efficacy of a group-based intervention for increasing physical activity (PA) among insufficiently active African American women. DESIGN: The TEAM-PA trial uses a group cohort design, is implemented at community sites, and will involve 360 African American women. The trial compares a 10-week group-based intervention vs. a standard group-delivered PA comparison program. Measures include minutes of total PA/day using 7-day accelerometer estimates (primary outcome), and body mass index, blood pressure, waist circumference, walking speed, sedentary behavior, light physical activity, and the percentage achieving ≥150 min of moderate to vigorous PA/week (secondary outcomes) at baseline, post-intervention, and 6-months post-intervention. INTERVENTION: The intervention integrates elements from Social Cognitive Theory, Self-Determination Theory, Group Dynamics Theory, and a focus on collectivism to evaluate different components of social affiliation (relatedness, reciprocal support, group cohesion, and collective efficacy). The intervention integrates shared goal-setting via Fitbits, group-based problem-solving, peer-to-peer positive communication, friendly competition, and cultural topics related to collectivism. Compared to the standard group-delivered PA program, participants in the intervention are expected to show greater improvements from baseline to post- and 6-month follow-up on minutes of total PA/day and secondary outcomes. Social affiliation variables (vs. individual-level factors) will be evaluated as mediators of the treatment effect. IMPLICATIONS: The results of the TEAM-PA trial will determine the efficacy of the intervention and identify which aspects of social affiliation are most strongly related to increased PA among African American women. TRIAL REGISTRATION: This study was registered on Clinicaltrials.gov (# NCT05519696) in August 2022 prior to initial participant enrollment.

Engagement With Tailored Physical Activity Content: Secondary Findings From the Families Improving Together for Weight Loss Randomized Controlled Trial.

BACKGROUND: Web-based tailored interventions offer rich opportunities for improved access to and personalization of behavioral interventions. However, despite the promise of this approach, the engagement and underrepresentation of minority groups remain major issues. OBJECTIVE: This study evaluated whether engagement (log-in status and log-in duration) with different types of tailored behavioral content from the Families Improving Together for weight loss web-based intervention was associated with changes in moderate to vigorous physical activity (MVPA) among African American families with overweight or obesity. METHODS: Parent-adolescent dyads were randomized to a web-based tailored intervention or web-based health education comparison program. The web-based intervention (N=119) was completed by parents and targeted 6 weight-related behaviors to support their adolescent children's weight loss goals (session contents included energy balance, fast food, fruits and vegetables, physical activity [PA], sedentary behavior, and sweetened beverages). MVPA was measured using accelerometers at baseline and after the intervention. RESULTS: Using a hierarchical approach, the log-in status and duration for each web-based session were used to evaluate the additive effects of engagement with different types of tailored behavioral content on MVPA after the web-based intervention. Among parents, logging in to the PA session was not associated with greater MVPA (B=-12.561, 95% CI -18.759 to -6.367), but MVPA increased with greater log-in duration for the PA (B=0.008, 95% CI 0.004-0.012) and sedentary behavior (B= 0.008, 95% CI 0.004-0.012) sessions. These results suggest that parents who logged in to the PA session had lower MVPA, but MVPA increased with greater log-in duration for the PA and sedentary behavior sessions. These associations remained even after accounting for engagement with other content sessions. However, these engagement effects did not translate to the adolescents. CONCLUSIONS: The results of this study highlight the need to disentangle the impact of engagement with different tailored content to improve the efficacy of tailored web-based interventions, especially for promoting PA in African American families. TRIAL REGISTRATION: ClinicalTrials.gov NCT01796067; https://clinicaltrials.gov/ct2/show/NCT01796067.

Buffering effects of protective factors on light and moderate-to-vigorous physical activity among african american women.

Physical activity (PA) plays an integral role in reducing risk for the leading causes of death and has also been shown to buffer stress. Based on the stress-buffering hypothesis, the present study examined whether protective factors (self-efficacy and informal social control) buffered the effects of perceived stress on PA over time. Secondary data analyses of female African American caregivers (N = 143) were conducted using data from the Families Improving Together (FIT) trial. Validated measures of stressors and protective factors were assessed at baseline. Light PA and moderate-to-vigorous PA were assessed using seven-day accelerometry estimates over sixteen weeks. Multilevel growth modeling was used to assess whether protective factors moderated the effects of perceived stress on PA outcomes across 16 weeks. There was a significant two-way interaction between informal social control and time (B = 0.40, SE = 0.17, p = .019) such that higher informal social control was positively associated with MVPA over time. There was a marginal three-way interaction (B = -18.90, SE = 10.31, p = .067) such that stress was associated with greater LPA at baseline under conditions of high but not low self-efficacy. This study provides preliminary support that social factors may be important for maintaining MVPA regardless of stress levels, while cognitive resources may be more important to target for influencing LPA engagement under conditions of high stress.

The Importance of Addressing Multilevel Transactional Influences of Childhood Obesity to Inform Future Health Behavior Interventions.

We provide a transactional model of health for understanding the early risk of obesity in youth. This model argues that positive health is construed through the choices and actions that youth take within the range of resources and constraints of their biological and contextual situations across time. Social, cognitive, affective, and behavioral regulatory/motivational processes within the child mediate the relation between life experiences and health outcomes and obesity pathways are influenced by cumulative risk or protective processes for health promotion/compromising behaviors influencing health. We provide evidence-based examples of multilevel approaches to obesity prevention and treatment and highlight recommendations for future health behavior interventions.

Results from "Developing Real Incentives and Volition for Exercise" (DRIVE): A pilot randomized controlled trial for promoting physical activity in African American women.

OBJECTIVE: Motivation is a barrier to physical activity (PA) among African American (AA) women, but past studies have implemented a "one-size-fits-all" approach and have not addressed differences in autonomous motivation. This pilot randomized controlled trial assessed the preliminary efficacy of "Developing Real Incentives and Volition for Exercise," a community- and theory-based intervention, which evaluated whether a motivationally matched (vs. a nonmatched) intervention increases daily total PA. METHOD: In total, 68 AA women (50.72 ± 13.66 years; 86.8% with obesity) were randomized to an 8-week challenge-focused program (targeted toward high autonomous motivation) or rewards-focused program (targeted toward low autonomous motivation). Randomization was stratified by baseline autonomous motivation. FitBits were used during the intervention to promote self-monitoring (both programs) and social connectedness (challenge program only). RESULTS: Both programs retained ≥ 80% of participants. Process evaluation revealed high attendance, dose, and fidelity (both programs). However, contrary to expectations, across all motivational levels (low and high autonomous), the challenge-focused intervention resulted in a greater increase in total daily PA (primary outcome), with an average increase of 17.9 min in the challenge-focused intervention versus an average decrease of 8.55 min in the rewards-focused intervention. An exploratory follow-up analysis revealed that engagement with the FitBit mobile app predicted greater PA at postintervention in the challenge-focused program. CONCLUSIONS: A team-based approach targeting social connectedness, enjoyment of PA, and positive intragroup competition is a promising approach for promoting PA among AA women. These findings are used to guide a discussion on best practices for engaging AA women in future behavioral interventions. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The Results of the Families Improving Together (FIT) for Weight Loss Randomized Trial in Overweight African American Adolescents.

BACKGROUND: Few intervention studies have integrated cultural tailoring, parenting, behavioral, and motivational strategies to address African American adolescent weight loss. PURPOSE: The Families Improving Together (FIT) for Weight Loss trial was a randomized group cohort study testing the efficacy of a cultural tailoring, positive parenting, and motivational intervention for weight loss in overweight African American adolescents (N = 241 adolescent/caregiver dyads). METHODS: The trial tested an 8-week face-to-face group motivational plus family weight loss program (M + FWL) compared with a comprehensive health education control program. Participants were then rerandomized to an 8-week tailored or control online program to test the added effects of the online intervention on reducing body mass index and improving physical activity (moderate-to-vigorous physical activity [MVPA], light physical activity [LPA]), and diet. RESULTS: There were no significant intervention effects for body mass index or diet. There was a significant effect of the group M + FWL intervention on parent LPA at 16 weeks (B = 33.017, SE = 13.115, p = .012). Parents in the group M + FWL intervention showed an increase in LPA, whereas parents in the comprehensive health education group showed a decrease in LPA. Secondary analyses using complier average causal effects showed a significant intervention effect at 16 weeks for parents on MVPA and a similar trend for adolescents. CONCLUSIONS: While the intervention showed some impact on physical activity, additional strategies are needed to impact weight loss among overweight African American adolescents.

Evaluating Experiences of Stress and Coping Among African American Women During the COVID-19 Pandemic to Inform Future Interventions.

BACKGROUND: African American (AA) women experience disproportionate levels of chronic disease, which is theorized to be driven by greater exposure to acute and chronic stress. The coronavirus (COVID-19) pandemic has further exacerbated existing health disparities among AA communities. Understanding how AA women have experienced and responded to stress during the pandemic may help to inform how future interventions can better address physical and mental well-being in AA communities. AIMS: Drawing from stress and coping models and an ecological framework, the present study conducted a theory-based qualitative assessment of stress-related experiences during the pandemic among a cohort of AA women, including (1) sources of stress, (2) coping strategies, (3) perceptions of health-related behaviors, (4) the role of community, and (5) recommendations for future interventions. METHOD: After completing a group-based physical activity intervention program during the COVID-19 pandemic, a cohort of AA women (N =17, Mage= 49.3 ± 11.24) completed individual interviews. Sessions were conducted by phone, audiotaped, transcribed, and coded by independent raters (rs = .71-.73). Themes were identified using deductive and inductive approaches. RESULTS: Among sources of stress directly related to the pandemic, being at home, getting sick, and homeschooling/parenting were the most frequently discussed themes. Participants engaged in active coping (problem and emotion-focused), with health behaviors, social support, and religion/spirituality, emerging as frequently discussed themes. Although some participants reported passive coping strategies (e.g., avoidance), this approach was less pronounced. CONCLUSIONS: These qualitative results are used to guide suggestions for future interventions that jointly address stress and health-related behaviors in order to improve translation of research into practice and policy for future pandemics and disasters.

Moderating Effects of Parental Feeding Practices and Emotional Eating on Dietary Intake among Overweight African American Adolescents.

This study examined the effects of parental feeding practices and adolescent emotional eating (EE) on dietary outcomes among overweight African American adolescents. Based on Family Systems Theory, it was hypothesized that parental feeding practices, such as parental monitoring and responsibility, would buffer the effects of EE on poor dietary quality, whereas practices such as concern about a child's weight, restriction, and pressure-to-eat would exacerbate this relationship. Adolescents (N = 127; Mage = 12.83 ± 1.74; MBMI% = 96.61 ± 4.14) provided baseline data from the Families Improving Together (FIT) for Weight Loss trial and an ancillary study. Dietary outcomes (fruit and vegetables (F&Vs), energy intake, sweetened beverage, total fat, and saturated fat) were assessed using random 24-h dietary recalls. Validated surveys were used to assess adolescent-reported EE and parental feeding practices. Results demonstrated a significant interaction between EE and parental monitoring (adjusted analyses; B = 0.524, SE = 0.176, p = 0.004), restriction (B = -0.331, SE = 0.162, p = 0.043), and concern (B = -0.602, SE = 0.171, p = 0.001) on F&V intake; under high monitoring, low restriction, and low concern, EE was positively associated with F&V intake. There were no significant effects for the other dietary outcomes. These findings indicate that parental feeding practices and EE may be important factors to consider for dietary interventions, specifically for F&V intake, among overweight African American adolescents.

The Moderating Effects of the Families Improving Together (FIT) for Weight Loss Intervention and Parenting Factors on Family Mealtime in Overweight and Obese African American Adolescents.

Few studies have integrated positive parenting and motivational strategies to address dietary outcomes such as frequency of family mealtime. The Families Improving Together (FIT) for Weight Loss trial was a randomized group cohort trial (n = 241 dyads) testing the efficacy of integrating a motivational plus family weight loss (M + FWL) intervention for healthy eating and weight loss in overweight and obese African American adolescents. The current study tested the interaction of parenting styles (responsiveness, demandingness) and parental feeding practices (restriction, concern about child's weight, pressure to eat) and the FIT intervention on frequency of family mealtime over 16 weeks. Multilevel modeling demonstrated significant interactions between the group-based treatment and responsiveness (p = 0.018) and demandingness (p = 0.010) on family mealtime. For the group-based M + FWL intervention, increased responsiveness and reduced demandingness were associated with increased frequency of family mealtime from baseline to 16 weeks. There was also a negative association between parental restriction and frequency of family mealtime, but a positive association between parental concerns about their adolescent's weight and frequency of mealtime. These findings are the first to demonstrate that an authoritative or nurturing parenting style moderated intervention effects for improving the frequency of family mealtime in overweight and obese African American adolescents.

Associations of parenting factors and weight related outcomes in African American adolescents with overweight and obesity.

This study evaluated the associations between parenting factors and adolescent weight related outcomes in African American adolescents with overweight and obesity. Baseline heights and weights were collected from 241 African American adolescents (11-16 years) with overweight and obesity. Self-reported adolescent perceptions of caregiver's parenting style (responsiveness, demandingness), parental feeding practices (monitoring, responsibility, weight related concerns, pressure-to-eat, and restriction), and their own dietary self-efficacy for healthy eating were assessed. Results demonstrated that greater parental responsiveness was significantly associated with lower adolescent body mass index (BMI) and higher adolescent dietary self-efficacy. In contrast, parental concern about adolescent weight was significantly associated with greater adolescent BMI, while greater parental responsibility for foods was associated with lower adolescent BMI. Although parental pressure-to-eat was significantly associated with higher dietary self-efficacy, greater parental restriction was associated with lower dietary self-efficacy. The results of this study highlight the importance of parental responsiveness and responsibility in understanding obesity related outcomes in African American adolescents with overweight and obesity.

Effects of Parenting and Perceived Stress on BMI in African American Adolescents.

OBJECTIVE: This study set out to examine the role of parenting practices in protecting or exacerbating the negative effects of parent and adolescent stress on adolescent body mass index (BMI) over time. Separate longitudinal models were conducted to evaluate how parenting practices interacted with parental perceived stress and adolescent perceived stress in predicting adolescent BMI. METHODS: Baseline data were collected from 148 African American adolescents (Mage = 12.93, SD = 1.75; Mz-BMI = 0.78, SD = 0.50; MBMI%-ile = 96.7, SD = 3.90) and their caregivers (Mage = 44.45, SD = 8.65; MBMI = 37.63, SD = 8.21) enrolled in the Families Improving Together for Weight Loss trial. Adolescents self-reported their perceptions of caregiver parenting style and feeding practices. Both caregivers and adolescents self-reported their perceptions of chronic stress. BMI for parents and adolescents was assessed objectively at baseline and 16 weeks post-intervention. RESULTS: Hierarchical regression models predicting adolescent BMI z-score (z-BMI) indicated a significant interaction between parental perceived stress and parental pressure to eat. Simple slopes analyses demonstrated that for those parents that exhibit higher pressure to eat, parent stress was positively associated with adolescent z-BMI. CONCLUSIONS: These findings provide preliminary support suggesting that certain parenting practices interact with chronic stress on adolescent weight-related outcomes and that future interventions may consider integrating these factors.

The role of parental support for youth physical activity transportation and community-level poverty in the healthy communities study.

This study evaluates whether parental provision of transportation for physical activity is associated with child/adolescent moderate-to-vigorous physical activity, while also evaluating community-level poverty. Self- and parental-reported surveys were administered with parents/caregivers and children in the Healthy Communities Study (N = 5138). Associations between individual-level demographics, community-level poverty, parental provision of transportation for physical activity, and moderate-to-vigorous physical activity were examined in multi-level models. Even when accounting for community-level poverty, which was significantly associated with lower moderate-to-vigorous physical activity, parental provision of transportation for physical activity was positively associated with greater moderate-to-vigorous physical activity. This study provides evidence for the importance of considering multiple systems of influence (e.g., community and individual factors) and considering how gaps in physical activity transportation for youth can be addressed in future health policies.

The Feasibility and Acceptability of the Developing Real Incentives and Volition for Exercise (DRIVE) Program: A Pilot Study for Promoting Physical Activity in African American Women.

Background. The purpose of the current article is to demonstrate how formative process evaluation was used in a pilot study to optimize the design and implementation of two motivationally targeted community-based physical activity (PA) interventions for inactive African American women. Method. Fifteen African American women (M age: 41.6 years) were randomized to a challenge-focused program targeted toward high autonomous motivation or a rewards-focused program targeted toward low autonomous motivation. The challenge-focused program targeted enjoyment and valuation of PA and a team-based positive social climate through competitive intergroup activities and team-based goals, whereas the rewards-focused program targeted PA interest, competency, and partner-based social support through a walking program, individual-based goals with financial incentives, and partner-based action-plans. Results. Feedback from participants revealed high levels of acceptability of essential elements. Average weekly attendance exceeded the a priori goal of ≥75% of members in attendance each week. External systematic observation demonstrated that session content dose was ≥93% in both programs. Facilitator-level fidelity exceeded the a priori goal of averaging ≥3 on a 4-point scale for behavioral skills, communication, autonomy support, and session content. The process evaluation also revealed areas for improvement, including facilitator-level social support and behavioral skills at the group-level. Process data collected through FitBits revealed that participants were engaged in self-monitoring PA during the 6-week programs. Conclusions. The formative process evaluation demonstrated adequate levels of feasibility and acceptability and also provided key insights into adjustments needed before proceeding with implementing the motivationally targeted group-based programs in a larger randomized study.

The Moderating Effects of Social Support and Stress on Physical Activity in African American Women.

BACKGROUND: African American women participate in less physical activity (PA), have higher rates of chronic disease, and report higher perceived stress relative to other race and sex demographic groups. PURPOSE: Based on the stress-buffering hypothesis, this study tested the hypothesis that social support would buffer the negative effects of perceived stress on moderate-to-vigorous PA (MVPA) under high, but not low, perceived stress. METHODS: Participants were 143 African American women (mean [M] age = 43.94, standard deviation [SD] = 8.62; M body mass index = 37.94, SD = 8.11) enrolled in the Families Improving Together (FIT) for Weight Loss Trial. Average daily minutes of MVPA were obtained via 7 day accelerometer estimates at baseline and 8 and 16 weeks. RESULTS: A multilevel growth model demonstrated a significant three-way interaction between stress, social support, and time (B = -0.31, standard error [SE] = 0.14, p = .03). Simple slopes analyses revealed that, at baseline, among participants with high social support (+1 SD), stress was positively associated with greater MVPA (B = 0.49, SE = 0.18, p = .008), whereas among participants with low social support (-1 SD), stress was not significantly associated with MVPA (B = -0.04, SE = 0.14, p = .81). However, at 8 and 16 weeks, stress was not significantly associated with MVPA for either high or low support groups. CONCLUSIONS: Findings highlight the importance of integrating constructs of stress and social support into future physical activity intervention programs for African American women and the need to evaluate changes in stress and social support longitudinally.

Interaction of Neighborhood and Genetic Risk on Waist Circumference in African-American Adults: A Longitudinal Study.

BACKGROUND: Understanding determinants of metabolic risk has become a national priority given the increasingly high prevalence rate of this condition among U.S. adults. PURPOSE: This study's aim was to assess the impact of gene-by-neighborhood social environment interactions on waist circumference (WC) as a primary marker of metabolic risk in underserved African-American adults. Based on a dual-risk model, it was hypothesized that those with the highest genetic risk and who experienced negative neighborhood environment conditions would demonstrate higher WC than those with fewer risk factors. METHODS: This study utilized a subsample of participants from the Positive Action for Today's Health environmental intervention to improve access and safety for walking in higher-crime neighborhoods, who were willing to provide buccal swab samples for genotyping stress-related genetic pathways. Assessments were conducted with 228 African-American adults at baseline, 12, 18, and 24 months. RESULTS: Analyses indicated three significant gene-by-environment interactions on WC outcomes within the sympathetic nervous system (SNS) genetic pathway. Two interactions supported the dual-risk hypotheses, including the SNS genetic risk-by-neighborhood social life interaction (b = -0.11, t(618) = -2.02, p = .04), and SNS genetic risk-by-informal social control interaction (b = -0.51, t(618) = -1.95, p = .05) on WC outcomes. These interactions indicated that higher genetic risk and lower social-environmental supports were associated with higher WC. There was also one significant SNS genetic risk-by-neighborhood satisfaction interaction (b = 1.48, t(618) = 2.23, p = .02) on WC that was inconsistent with the dual-risk pattern. CONCLUSIONS: Findings indicate that neighborhood and genetic factors dually influence metabolic risk and that these relations may be complex and warrant further study. TRIAL REGISTRATION: NCT01025726.

Conditional DnaB Protein Splicing Is Reversibly Inhibited by Zinc in Mycobacteria.

Inteins, as posttranslational regulatory elements, can tune protein function to environmental changes by conditional protein splicing (CPS). Translated as subdomains interrupting host proteins, inteins splice to scarlessly join flanking sequences (exteins). We used DnaB-intein1 (DnaBi1) from a replicative helicase of Mycobacterium smegmatis to build a kanamycin intein splicing reporter (KISR) that links splicing of DnaBi1 to kanamycin resistance. Using expression in heterologous Escherichia coli, we observed phenotypic classes of various levels of splicing-dependent resistance (SDR) and related these to the insertion position of DnaBi1 within the kanamycin resistance protein (KanR). The KanR-DnaBi1 construct demonstrating the most stringent SDR was used to probe for CPS of DnaB in the native host environment, M. smegmatis We show here that zinc, important during mycobacterial pathogenesis, inhibits DnaB splicing in M. smegmatis Using an in vitro reporter system, we demonstrated that zinc potently and reversibly inhibited DnaBi1 splicing, as well as splicing of a comparable intein from Mycobacterium leprae Finally, in a 1.95 Å crystal structure, we show that zinc inhibits splicing through binding to the very cysteine that initiates the splicing reaction. Together, our results provide compelling support for a model whereby mycobacterial DnaB protein splicing, and thus DNA replication, is responsive to environmental zinc.IMPORTANCE Inteins are present in a large fraction of prokaryotes and localize within conserved proteins, including the mycobacterial replicative helicase DnaB. In addition to their extensive protein engineering applications, inteins have emerged as environmentally responsive posttranslational regulators of the genes that encode them. While several studies have shown compelling evidence of conditional protein splicing (CPS), examination of splicing in the native host of the intein has proven to be challenging. Here, we demonstrated through a number of measures, including the use of a splicing-dependent sensor capable of monitoring intein activity in the native host, that zinc is a potent and reversible inhibitor of mycobacterial DnaB splicing. This work also expands our knowledge of site selection for intein insertion within nonnative proteins, demonstrating that splicing-dependent host protein activation correlates with proximity to the active site. Additionally, we surmise that splicing regulation by zinc has mycobacteriocidal and CPS application potential.