Dietary restraint and negative affect as mediators of body dissatisfaction and bulimic behavior in adolescent girls and boys

Stice's dual pathway model of dietary restraint and negative affect was examined in both adolescent girls and boys. Self-report measures assessing body dissatisfaction, dietary restraint, negative affect and bulimic behavior were administered to 267 girls and 199 boys aged between 12 and 16 years. The findings for the girls were consistent with Stice's model, in that they indicated that both dietary restraint and negative affect mediated the relationship between body dissatisfaction and bulimic behavior. For the boys who desired a thinner body size, only negative affect was found to mediate the relationship between body dissatisfaction and bulimic behavior. On the other hand, for boys who desired a larger body size, both body dissatisfaction and dietary restraint were found to exert an independent effect on bulimic behavior. As boys can aspire to two contrasting and seemingly opposite body size ideals, the findings highlight that the relationship between body dissatisfaction, dietary restraint, negative affect and bulimic behavior are more complex in males than in females. Further research using longitudinal designs is needed in order to test the directional and bidirectional nature of the observed interrelationships.

Socio-economic inequalities in women`s fruit and vegetable intakes: a multilevel study of individual, social and environmental mediators

Objective: This study employed a multilevel design to test the contribution of individual, social and environmental factors to mediating socio-economic status (SES) inequalities in fruit and vegetable consumption among women. Design: A cross-sectional survey was linked with objective environmental data. Setting: A community sample involving 45 neighbourhoods. Subjects: In total, 1347 women from 45 neighbourhoods provided survey data on their SES (highest education level), nutrition knowledge, health considerations related to food purchasing, and social support for healthy eating. These data were linked with objective environmental data on the density of supermarkets and fruit and vegetable outlets in local neighbourhoods. Results: Multilevel modelling showed that individual and social factors partly mediated, but did not completely explain, SES variations in fruit and vegetable consumption. Store density did not mediate the relationship of SES with fruit or vegetable consumption. Conclusions: Nutrition promotion interventions should focus on enhancing nutrition knowledge and health considerations underlying food purchasing in order to promote healthy eating, particularly among those who are socio-economically disadvantaged. Further investigation is required to identify additional potential mediators of SES–diet relationships, particularly at the environmental level.

Mediators of the relationship between maternal education and children's TV viewing

Background: Maternal education is consistently found to be inversely related to children’s television viewing and is associated with aspects of the family television environment. This study investigates whether family television environment mediates the relationship between maternal education and children’s television viewing.

Methods: Parents of 1484 children reported maternal education, time their child spends watching television, and 21 aspects of the family television environment (potential mediators) during 2002 and 2003. Separate regression analyses were conducted in 2006 for each potential mediator that met two initial conditions for mediation (associated with both maternal education and children’s television viewing (p<0.10)), to assess whether inclusion reduced the association between maternal education and children’s television viewing. Multivariable regression assessed the combined impact of all mediators.

Results: Twelve of 21 potential mediators met the initial conditions for mediation. Inclusion of each resulted in decreased β values (3.2% to 15.2%) for the association between maternal education and television viewing. Number and placement of televisions in the home appeared to have the greatest mediating effect, followed by frequency of eating dinner in front of the television with the child and rules about television viewing during mealtimes. Together, the 12 mediators accounted for more than one-third of the association between maternal education and children’s television viewing time.

Conclusions: This study suggests the strong inverse relationship between maternal education and children’s television viewing is partly mediated by aspects of the family television environment.

Effects of strategies to promote children's physical activity on potential mediators

The aim of this paper is to review evidence of the effectiveness of interventions that present physical activity outcomes and potential mediators of behavioural change among 4–12-year-old children. A systematic search of electronic databases for original research articles published in peer-review journals between January 1985 and the end of June 2006 was carried out. A total of 19 studies that reported intervention effects on physical activity and mediators of behavioural change were identified. The most common mediators reported included physical activity knowledge or beliefs (11 studies); self-efficacy (8 studies); and enjoyment or preference for physical activity (6 studies). Less frequently reported mediators included attitudes, behavioural capability, intentions, outcome expectancies, social norms, social support and self-concept. Seven of the 11 interventions that reported intervention effects on knowledge/beliefs stated positive changes in this mediator. Four of the eight studies that reported intervention effects on self-efficacy had significant improvements; however, only two out of six interventions reported significant improvements in physical activity enjoyment or preference. None of the studies reviewed reported whether changes in these constructs mediated changes in children's physical activity behaviours. Although more than half of the studies reviewed reported a positive intervention effect on children's physical activity, no study carried out a mediating analysis to attempt to identify the mechanisms of change. Future research should more clearly identify the mediators of behavioural change that are being targeted and whether this explains intervention effects.

Effect of exercise and protein on skeletal muscle inflammatory mediators

Intense exercise results in muscular inflammation. Molecular techniques were used to identify novel inflammatory proteins in human muscle. Males and females displayed different levels of exercise-induced inflammatory proteins. Interestingly, dairy protein supplements reduced these inflammatory proteins post-exercise. Increased dietary red meat consumption, with training, had no impact on muscle inflammation, although strength gain was improved.

Perceived neighborhood environment and park use as mediators of the effect of area socio-economic status on walking behaviors

Background: Access to local parks can affect walking levels. Neighborhood environment and park use may influence relationships between neighborhood socioeconomic status (SES) and walking.

Methods: Self-report data on perceived park features, neighborhood environment, park use, neighborhood walking and sociodemographics
were obtained from a sample of Australian adults, living in high/low SES areas. Surveys were mailed to 250 randomly selected households within 500m of 12 matched parks. Mediating effects of perceived environment attributes and park use on relationships between area-SES and walking were examined.

Results: Mean frequency of local park use was higher for high-SES residents (4.36 vs 3.16 times/wk, P < .01), who also reported higher levels of park safety, maintenance, attractiveness, opportunities for socialization, and neighborhood crime safety, aesthetics, and traffic safety. Safety and opportunity for socialization were independently positively related to monthly frequency of visits to a local park which, in turn, was positively associated with walking for recreation and total walking. Residents of higher SES areas reported an average 22% (95% CI: 5%, 37%) more weekly minutes of recreational walking than their low SES counterparts.

Conclusion: Residents of high-SES areas live in environments that promote park use, which positively contributes to their weekly amounts of overall and recreational walking.

Validity and reliability of instruments to assess potential mediators of children's physical activity : a systematic review

This paper aimed to (1) identify potential mediators reported in children's physical activity interventions; and (2) review the psychometric properties of measures of potential mediators included in such interventions. A systematic search of the literature was conducted and studies that reported potential mediators and/or the psychometric properties of measures of potential mediators were retrieved and reviewed. The studies were reviewed for the following psychometric properties: face/logical, construct, and criterion validity; and test–retest and internal consistency (factor analysis and Cronbach's α) reliability. Twenty-one potential mediators were identified from 24 published children's physical activity intervention studies; 17 individual, three social, and one physical environmental. Overall, there was considerable variation in the reporting of the psychometric properties of these measures. Reliability properties (specifically Cronbach's α) were more commonly reported than validity properties; however, for many potential mediators, the quality of these measures was low. Future studies should examine the psychometric properties of measures of potential mediators to ensure appropriate, valid and reliable instruments are used. This will assist in the ability to accurately determine the efficacy of physical activity interventions among children.

Developing negotiation decision support systems that support mediators : a case study of the Family_Winner system

Negotiation Support Systems have traditionally modelled the process of negotiation. They often rely on mathematical optimisation techniques and ignore heuristics and other methods derived from practice. Our goal is to develop systems capable of decision support to help resolve a given dispute. A system we have constructed, Family_Winner, uses empirical evidence to dynamically modify initial preferences throughout the negotiation process. It sequentially allocates issues using trade-offs and compensation opportunities inherent in the dispute.

Coping strategies and social support as predictors and mediators of eating disorder carer burden and psychological distress

Purpose Caring for someone with an eating disorder is associated with a high level of burden and psychological distress. While models for the prediction of carer burden have previously been investigated, these have typically neglected the role of coping strategies and social support. Thus, the current study will examine predictors of both carer burden and carer psychological distress in eating disorder carers. Further, the mediating roles of coping strategies and social support will be investigated.
Methods Fifty-six carers completed a self-report questionnaire assessing burden, psychological distress, needs, expressed emotion, coping strategies and social support.
Results Use of maladaptive coping strategies was a unique predictor of both burden and psychological distress. Further, maladaptive coping was a consistent mediator on the outcome of carer burden. Social support, however, did not significantly predict, or mediate, carer burden.
Conclusions Interventions focusing on teaching appropriate coping strategies would benefit carers.

Early age alcohol use and later alcohol problems in adolescents : individual and peer mediators in a bi-national study

This paper examines whether there is cross-national similarity in the longitudinal relationship between early age alcohol use and adolescent alcohol problems. Potential mechanisms underlying this relationship also are examined, testing adolescent alcohol use, low self-regulation, and peer deviance as possible mediators. Students (N = 1,945) participating in the International Youth Development Study, a longitudinal panel survey study, responded to questions on alcohol use and influencing factors, and were followed annually over a 3-year period from 2002 to 2004 (98% retention rate). State-representative, community student samples were recruited in grade 7 in Washington State, United States (US, n = 961, 78% of those eligible; Mage = 13.09, SD = .44) and Victoria, Australia (n = 984, 76% of those eligible; Mage = 12.93, SD = .41). Analyses were conducted using multiple-group structural equation modeling. In both states, early age alcohol use (age 13) had a small but statistically significant association with subsequent alcohol problems (age 15). Overall, there was little evidence for mediation of early alcohol effects. Low self-regulation prospectively predicted peer deviance, alcohol use, and alcohol problems in both states. Peer deviance was more positively related to alcohol use and low self-regulation among students in Victoria compared to students in Washington State. The small but persistent association of early age alcohol use with alcohol problems across both samples is consistent with efforts to delay alcohol initiation to help prevent problematic alcohol use. Self-regulation was an important influence, supporting the need to further investigate the developmental contribution of neurobehavioral disinhibition.

Mediators of longitudinal associations between television viewing and eating behaviours in adolescents

Background: Television viewing has been associated with poor eating behaviours in adolescents. Changing unhealthy eating behaviours is most likely to be achieved by identifying and targeting factors shown to mediate the association between these behaviours. However, little is known about the mediators of the associations between television viewing and eating behaviours. The aim of this study was to examine mediators of the longitudinal associations between television viewing (TV) and eating behaviours among Australian adolescents.
Method: Eating behaviours were assessed using a web-based survey completed by a community-based sample of 1729 adolescents from years 7 and 9 of secondary schools in Victoria, Australia, at baseline (2004-2005) and two years later. TV viewing and the potential mediators (snacking while watching TV and perceived value of TV viewing) were assessed via the web-based survey at baseline.
Results: Adolescents who watched more than two hours of TV/day had higher intakes of energy-dense snacks and beverages, and lower intakes of fruit two years later. Furthermore, the associations between TV viewing and consumption of energy-dense snacks, energy-dense drinks and fruit were mediated by snacking while watching TV. Perceived value of TV viewing mediated the association between TV viewing and consumption of energy-dense snacks, beverages and fruit.
Conclusion: Snacking while watching TV and perceived value of TV viewing mediated the longitudinal association between TV viewing and eating behaviours among adolescents. The efficacy of methods to reduce TV viewing, change snacking habits while watching TV, and address the values that adolescents place on TV viewing should be examined in an effort to promote healthy eating among adolescents.