Changes in weight status, quality of life and behaviours of South Australian primary school children: results from the Obesity Prevention and Lifestyle (OPAL) community intervention program.

BACKGROUND: Childhood obesity is a serious public health concern worldwide. Community-based obesity prevention interventions offer promise due to their focus on the broader social, cultural and environmental contexts rather than individual behaviour change and their potential for sustainability and scalability. This paper aims to determine the effectiveness of a South Australian community-based, multi-setting, multi-strategy intervention, OPAL (Obesity Prevention and Lifestyle), in increasing healthy weight prevalence in 9 to 11-year-olds. METHODS: A quasi-experimental repeated cross-sectional design was employed. This paper reports on the anthropometric, health-related quality of life (HRQoL) and behaviour outcomes of primary school children (9-11 years) after 2-3 years of intervention delivery. Consenting children from primary schools (20 intervention communities, INT; 20 matched comparison communities, COMP) completed self-report questionnaires on diet, activity and screen time behaviours. HRQoL was measured using the Child Health Utility 9D. Body Mass Index (BMI) z-score and weight status were determined from children's measured height and weight. A multilevel mixed-effects model, accounting for clustering in schools, was implemented to determine intervention effect. Sequential Bonferroni adjustment was used to allow for multiple comparisons of the secondary outcomes. RESULTS: At baseline and final, respectively, 2611 and 1873 children completed questionnaires and 2353 and 1760 had anthropometric measures taken. The prevalence of children with healthy weight did not significantly change over time in INT (OR 1.11, 95%CI 0.92-1.35, p = 0.27) or COMP (OR 0.85, 95%CI 0.68-1.06, p = 0.14). Although changes in the likelihood of obesity, BMI z-score and HRQoL favoured the INT group, the differences were not significant after Bonferroni adjustment. There were also no significant differences between groups at final for behavioural outcomes. CONCLUSIONS: OPAL did not have a significant impact on the proportion of 9 to 11-year-olds in the healthy weight range, nor children's BMI z-score, HRQoL and behaviours. Long-term, flexible community-based program evaluation approaches are required . TRIAL REGISTRATION: ACTRN12616000477426 (12th April 2016, retrospectively registered).

Social marketing and community mobilisation to reduce underage alcohol consumption in Australia: A cluster randomised community trial.

BACKGROUND AND AIMS: In many countries adolescent alcohol use is a major health problem. To supplement national policies, it is important to trial community interventions as a potential strategy to prevent adolescent alcohol use. METHODS: This study evaluated a multicomponent community intervention that included community mobilisation, social marketing, and the monitoring of alcohol sales to minors. Evaluation was a clustered randomised trial design with 14 intervention and 14 control communities. Prior to randomisation, communities were matched on socioeconomic status and location. Intervention communities were not blinded. PARTICIPANTS: 3545 Year 8 students (M = 12 years) were surveyed at baseline from 75 schools; 3377 students were surveyed post intervention in 2013 from 54 schools. OUTCOMES: It was hypothesised that the primary outcome, individual alcohol consumption in last 30 days, after the intervention would be 15% lower in intervention communities. Secondary outcomes were consumption in the past year and intention not to drink before age 18. RESULTS: The intervention communities showed larger relative reductions compared to the controls in last 30-day consumption and past year (10%), but not significantly different. A significantly lower proportion of participants in the intervention community (63%), compared to the controls (71%), reported intending to drink before 18 years old. Subgroup analysis identified regional and state differences for some secondary measures. CONCLUSIONS: Intervention assignment was associated with lower adolescent intention to drink before the age of 18. However, more intensive and longer-term intervention may be required to measure significant differences in behaviour change. TRIAL REGISTRATION: ACTRN12612000384853. PROTOCOL: Rowland B, Toumbourou JW, Osborn A, et al. BMJ Open 2013;3:e002423. doi:10.1136/bmjopen-2012-002423.

Relationship between the home environment and fruit and vegetable consumption in children aged 6-12 years: a systematic review.

OBJECTIVE: As numerous factors in the home environment have been related to children's fruit and vegetable (F&V) consumption as a component of a healthy diet, the purpose of the present systematic review was to examine these factors specifically for children aged 6-12 years. DESIGN: Relevant observational studies published in English between January 2007 and December 2015 were obtained through electronic database searches. Studies were included if the researchers reported on a potentially modifiable measure of the home physical, political and sociocultural environment related to child F&V consumption. RESULTS: Of the thirty-three articles reviewed, overall methodological quality was poor with twenty studies rated as weak, mainly due to cross-sectional design (majority of studies), selection bias, convenience sampling and voluntary participation. Half of the studies had strong-moderate ratings for using valid and/or reliable tools while for the other half, psychometric properties were either not reported or weak. The most consistent evidence for children's combined F&V consumption was found for availability and accessibility of F&V, parental role modelling of F&V and maternal intake of F&V. CONCLUSIONS: A vast array of home environment components and their influence on children's consumption of fruits and/or vegetables have been studied in recent years. Specific components of the home environment may have more influence than others, but more compelling evidence is needed to draw strong conclusions. Recommendations are made for future studies to be based upon conceptual/theoretical models to provide consistency in defining the home environment and investigation of potential moderators, such as personal or contextual factors.

Positive influences of home food environment on primary-school children's diet and weight status: a structural equation model approach.

OBJECTIVES: The mechanism by which the home food environment (HFE) influences childhood obesity is unclear. The present study aimed to investigate the relationship between HFE and childhood obesity as mediated by diet in primary-school children. DESIGN: Cross-sectional data collected from parents and primary-school children participating in the Obesity Prevention and Lifestyle Evaluation Project. Only children aged 9-11 years participated in the study. Matched parent/child data (n 3323) were analysed. Exploratory factor analysis underlined components of twenty-one HFE items; these were linked to child diet (meeting guidelines for fruit, vegetable and non-core food intakes) and measured child BMI, in structural equation modelling, adjusting for confounders. SETTING: Twenty geographically bounded metropolitan and regional South Australian communities. SUBJECTS: School children and their parents from primary schools in selected communities. RESULTS: In the initial exploratory factor analysis, nineteen items remaining extracted eight factors with eigenvalues >1·0 (72·4 % of total variance). A five-factor structure incorporating ten items described HFE. After adjusting for age, gender, socio-economic status and physical activity all associations in the model were significant (P<0·05), explaining 9·3 % and 4·5 % of the variance in child diet and BMI, respectively. A more positive HFE was directly and indirectly associated with a lower BMI in children through child diet. CONCLUSIONS: The robust statistical methodology used in the present study provides support for a model of direct and indirect dynamics between the HFE and childhood obesity. The model can be tested in future longitudinal and intervention studies to identify the most effective components of the HFE to target in childhood obesity prevention efforts.

Effectiveness of a Randomized Controlled Lifestyle Intervention to Prevent Obesity among Chinese Primary School Students: CLICK-Obesity Study.

BACKGROUND: Childhood obesity has been increasing rapidly worldwide. There is limited evidence for effective lifestyle interventions to prevent childhood obesity worldwide, especially in developing countries like China. The objective of this study was to assess the effectiveness of a school-based multi-component lifestyle childhood obesity prevention program (the CLICK-Obesity study) in Mainland China. METHODS: A cluster randomized controlled trial was developed among grade 4 students from 8 urban primary schools (638 students in intervention, 544 as control) in Nanjing City, China. Students were randomly allocated to the control or intervention group at school-level. A one-year multi-component intervention program (classroom curriculum, school environment support, family involvement and fun programs/events) together with routine health education was provided to the intervention group, while the control group received routine health education only. The main outcome variables assessed were changes in body mass index, obesity occurrence, obesity-related lifestyle behaviors and knowledge. RESULTS: Overall, 1108 (93.7%) of the 1182 enrolled students completed the intervention study. The intervention group had a larger marginal reduction than did the control group in overall mean BMI value (-0.32±1.36 vs. -0.29±1.40, p = 0.09), although this was not significant. Compared with the control group, the intervention group was more likely to decrease their BMI (OR = 1.44, 95%CI = 1.10, 1.87) by 0.5 kg/m2 or above, increase the frequency of jogging/running (OR = 1.55, 95%CI = 1.18, 2.02), decrease the frequency of TV/computer use (OR = 1.41, 95%CI = 1.09, 1.84) and of red meat consumption (OR = 1.50, 95%CI = 1.15, 1.95), change commuting mode to/from school from sedentary to active mode (OR = 2.24, 95%CI = 1.47, 3.40), and be aware of the harm of selected obesity risk factors. CONCLUSIONS: The school-based lifestyle intervention program was practical and effective in improving health behaviors and obesity-related knowledge for children in China. This study provides important policy implications on school-based intervention programs for modifications of obesity-related lifestyles. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR-ERC-11001819.

Critical design features for establishing a childhood obesity monitoring program in Australia.

Efforts to combat childhood obesity in Australia are hampered by the lack of quality epidemiological data to routinely monitor the prevalence and distribution of the condition. This paper summarises the literature on issues relevant to childhood obesity monitoring and makes recommendations for implementing a school-based childhood obesity monitoring program in Australia. The primary purpose of such a program would be to collect population-level health data to inform both policy and the development and evaluation of community-based obesity prevention interventions. Recommendations are made for the types of data to be collected, data collection procedures and program management and evaluation. Data from an obesity monitoring program are crucial for directing and informing policies, practices and services, identifying subgroups at greatest risk of obesity and evaluating progress towards meeting obesity-related targets. Such data would also increase the community awareness necessary to foster change.

BMI, health behaviors, and quality of life in children and adolescents: a school-based study.

OBJECTIVE: To explore the relationship between weight status (BMI) and health-related quality of life in children and adolescents through application of the Child Health Utility 9D, a new generic preference-based instrument. METHODS: Data were collected from primary and high school students in rural and metropolitan regions of South Australia. Consenting participants (2588 in grades 4-6 and 765 in grades 9-10) were weighed and measured and categorized as underweight, healthy weight, overweight, or obese according to International Obesity Taskforce BMI cutoff points (primary outcome). Participants also completed a questionnaire including the Child Health Utility 9D and standardized measures of physical activity, sedentary behavior, sleep patterns, and eating behavior (secondary outcomes). Descriptive and multivariate linear regression analyses were undertaken to calculate mean utility differences. RESULTS: In comparison with healthy-weight primary school students, adjusted mean utilities were lower for overweight (-0.016, P = .02) or obese (-0.039, P = .001) students. For high school students, the adjusted mean utilities were also lower for overweight and obese students but were nonsignificant (-0.018, P > .10). Physical activity, sedentary behavior, sleep patterns, and eating behavior were all found to be significantly associated with utilities. CONCLUSIONS: Irrespective of BMI, young people engaging in more physical activities or less sedentary behavior, and having healthier sleep patterns or eating behavior exhibited higher utilities. Associations between utilities and sleep patterns or eating behavior were stronger than the associations with BMI. Future economic evaluations for obesity interventions should more formally investigate the relationship between changes over time in weight status and health-related quality of life for children and adolescents.

Physical activity, leisure-time screen use and depression among children and young adolescents.

OBJECTIVES: Adolescent mental disorders remain a relatively neglected area of research, despite evidence that these conditions affect youth disproportionately. We examined associations between physical activity, leisure-time screen use and depressive symptoms among Australian children and adolescents. DESIGN: Large cross-sectional observational study. METHODS: Self-reported physical activity and leisure-time screen behaviours, and depressive symptoms using the Short Mood and Feeling Questionnaire were assessed in 8256 students aged 10-16 years (mean age=11.5 years, SD=0.8). RESULTS: Thirty three percent of the sample reported moderate to high depressive symptoms, with rates higher among females (OR=1.18; 95% CI: 1.02, 1.36; p=0.001). Increased opportunities to be active at school outside class (OR=0.70; 0.58, 0.85; p<0.001), being active in physical education classes (OR=0.77; 0.69, 0.86; p<0.001), greater involvement in sports teams at school (OR=0.77; 0.67, 0.88; p<0.001) and outside of school (OR=0.84; 0.73, 0.96; p=0.01) were all independently associated with lower odds for depressive symptoms. Meeting recommended guidelines for physical activity (OR=0.62; 0.44, 0.88; p=0.007) and, for 12-14 year olds, leisure-time screen use (OR=0.77; 0.59, 0.99; p=0.04) were also independently associated with lower odds for depressive symptoms. CONCLUSIONS: Higher levels of physical activity among children and young adolescents, and lower levels of leisure-time screen use among young adolescents, are associated with lower depressive symptoms. Longitudinal studies are needed to understand the causal relationships between these variables.

Initiating and maintaining recreational walking: a longitudinal study on the influence of neighborhood green space.

OBJECTIVE: This study examined prospective relationships of green space attributes with adults initiating or maintaining recreational walking. METHODS: Postal surveys were completed by 1036 adults living in Adelaide, Australia, at baseline (two time points in 2003-04) and follow-up (2007-08). Initiating or maintaining recreational walking was determined using self-reported walking frequency. Green space attributes examined were perceived presence, quality, proximity, and the objectively measured area (total and largest) and number of green spaces within a 1.6 km buffer drawn from the center of each study neighborhood. Multilevel regression analyses examined the odds of initiating or maintaining walking separately for each green space attribute. RESULTS: At baseline, participants were categorized into non-regular (n = 395), regular (n = 286), and irregular walkers (n = 313). Among non-regular walkers, 30% had initiated walking, while 70% of regular walkers had maintained walking at follow-up. No green space attributes were associated with initiating walking. However, positive perceptions of the presence of and proximity to green spaces and the total and largest areas of green space were significantly associated with a higher likelihood of walking maintenance over four years. CONCLUSION: Neighborhood green spaces may not assist adults to initiate walking, but their presence and proximity may facilitate them to maintain recreational walking over time.

A clustered randomised trial examining the effect of social marketing and community mobilisation on the age of uptake and levels of alcohol consumption by Australian adolescents.

INTRODUCTION: Throughout the world, alcohol consumption is common among adolescents. Adolescent alcohol use and misuse have prognostic significance for several adverse long-term outcomes, including alcohol problems, alcohol dependence, school disengagement and illicit drug use. The aim of this study was to evaluate whether randomisation to a community mobilisation and social marketing intervention reduces the proportion of adolescents who initiate alcohol use before the Australian legal age of 18, and the frequency and amount of underage adolescent alcohol consumption. METHOD AND ANALYSIS: The study comprises 14 communities matched with 14 non-contiguous communities on socioeconomic status (SES), location and size. One of each pair was randomly allocated to the intervention. Baseline levels of adolescent alcohol use were estimated through school surveys initiated in 2006 (N=8500). Community mobilisation and social marketing interventions were initiated in 2011 to reduce underage alcohol supply and demand. The setting is communities in three Australian states (Victoria, Queensland and Western Australia). Students (N=2576) will complete school surveys in year 8 in 2013 (average age 12). PRIMARY OUTCOMES: (1) lifetime initiation and (2) monthly frequency of alcohol use. Reports of social marketing and family and community alcohol supply sources will also be assessed. Point estimates with 95% CIs will be compared for student alcohol use in intervention and control communities. Changes from 2006 to 2013 will be examined; multilevel modelling will assess whether random assignment of communities to the intervention reduced 2013 alcohol use, after accounting for community level differences. Analyses will also assess whether exposure to social marketing activities increased the intervention target of reducing alcohol supply by parents and community members. TRIAL REGISTRATION: ACTRN12612000384853.

Don't worry, be active: positive affect and habitual physical activity.

OBJECTIVE: The aim of ths study was to examine the association between habitual physical activity and positive and negative affect. METHOD: This cross-sectional study included 276 women aged 20 +, from the Geelong Osteoporosis Study. Habitual physical activity and other lifestyle exposures were assessed by questionnaire, concurrent with anthropometric assessments. Physical activity was categorized as very active, moderately active or sedentary. Positive and negative affect scores were derived from the validated 20 item Positive and Negative Affect Schedule (PANAS) self-report and were categorized into tertiles. RESULTS: There was a pattern of lower positive affect scores for lower levels of physical activity. With very active as the reference category, the odds for having a positive affect score in the highest tertile were sequentially lower for those who were moderately active (OR = 0.53, 95%CI 0.28-1.01) and sedentary (OR = 0.28, 95%CI 0.10-0.75). Associations were sustained after adjusting for body mass index and polypharmacy (OR = 0.50, 95%CI 0.26-0.96 and OR = 0.25, 95%CI 0.09-0.72, respectively). These associations were not explained by age, negative affect score or other exposures. No association was detected between physical activity and negative affect scores. CONCLUSIONS: This study reports that higher positive affect scores, encompassing emotions such as interest, excitement, enthusiasm and alertness, are associated with higher levels of habitual physical activity. These observations warrant further investigations into possible mechanistic interplay between neurobiological and psychosocial factors that underpin this association.

A prospective study of diet quality and mental health in adolescents.

OBJECTIVES: A number of cross-sectional and prospective studies have now been published demonstrating inverse relationships between diet quality and the common mental disorders in adults. However, there are no existing prospective studies of this association in adolescents, the onset period of most disorders, limiting inferences regarding possible causal relationships. METHODS: In this study, 3040 Australian adolescents, aged 11-18 years at baseline, were measured in 2005-6 and 2007-8. Information on diet and mental health was collected by self-report and anthropometric data by trained researchers. RESULTS: There were cross-sectional, dose response relationships identified between measures of both healthy (positive) and unhealthy (inverse) diets and scores on the emotional subscale of the Pediatric Quality of Life Inventory (PedsQL), where higher scores mean better mental health, before and after adjustments for age, gender, socio-economic status, dieting behaviours, body mass index and physical activity. Higher healthy diet scores at baseline also predicted higher PedsQL scores at follow-up, while higher unhealthy diet scores at baseline predicted lower PedsQL scores at follow-up. Improvements in diet quality were mirrored by improvements in mental health over the follow-up period, while deteriorating diet quality was associated with poorer psychological functioning. Finally, results did not support the reverse causality hypothesis. CONCLUSION: This study highlights the importance of diet in adolescence and its potential role in modifying mental health over the life course. Given that the majority of common mental health problems first manifest in adolescence, intervention studies are now required to test the effectiveness of preventing the common mental disorders through dietary modification.

Habitual physical activity and the risk for depressive and anxiety disorders among older men and women.

BACKGROUND: Regular physical activity is generally associated with psychological well-being, although there are relatively few prospective studies in older adults. We investigated habitual physical activity as a risk factor for de novo depressive and anxiety disorders in older men and women from the general population. METHODS: In this nested case-control study, subjects aged 60 years or more were identified from randomly selected cohorts being followed prospectively in the Geelong Osteoporosis Study. Cases were individuals with incident depressive or anxiety disorders, diagnosed using the Structured Clinical Interview for DSM-IV-TR (SCID-I/NP); controls had no history of these disorders. Habitual physical activity, measured using a validated questionnaire, and other exposures were documented at baseline, approximately four years prior to psychiatric interviews. Those with depressive or anxiety disorders that pre-dated baseline were excluded. RESULTS: Of 547 eligible subjects, 14 developed de novo depressive or anxiety disorders and were classified as cases; 533 controls remained free of disease. Physical activity was protective against the likelihood of depressive and anxiety disorders; OR = 0.55 (95% CI 0.32-0.94), p = 0.03; each standard deviation increase in the transformed physical activity score was associated with an approximate halving in the likelihood of developing depressive or anxiety disorders. Leisure-time physical activity contributed substantially to the overall physical activity score. Age, gender, smoking, alcohol consumption, weight and socioeconomic status did not substantially confound the association. CONCLUSION: This study provides evidence consistent with the notion that higher levels of habitual physical activity are protective against the subsequent risk of development of de novo depressive and anxiety disorders.

Relationships of land use mix with walking for transport: do land uses and geographical scale matter?

Physical activity and public health recommendations now emphasize the creation of activity-friendly neighborhoods. Mixed land use in a neighborhood is important in this regard, as it reflects the availability of destinations to which residents can walk or ride bicycles, and thus is likely to contribute to residents' active lifestyles that in turn will influence their overall health. Relationships between land use mix (LUM) and physical activity have not been apparent in some studies, which may be because geographical scale and the specificity of hypothesized environment-behavior associations are not taken into account. We compared the strength of association of four Geographic Information Systems-derived LUM measures with walking for transport and perceived proximity to destinations. We assessed physical activity behaviors of 2,506 adults in 154 Census Collection Districts (CCDs) in Adelaide, Australia, for which ''original'' LUM measures were calculated, and then refined by either: accounting for the geographic scale of measurement; including only the most-relevant land uses; or, both. The refined (but not the ''original'') LUM measures had significant associations with the frequency of walking for transport (p < 0.05) and area-corrected measures had significant associations with the duration of walking for transport. All LUM measures had significant associations with perceived proximity to destinations, but stronger associations were seen when using the refined measures compared with the original LUM. Identifying the LUM attributes most strongly associated with walking for transport is a priority and can inform environmental and policy initiatives that are needed to promote health-enhancing physical activity.

The importance of family management, closeness with father and family structure in early adolescent alcohol use.

AIMS: To examine the importance of family management, family structure and father-adolescent relationships on early adolescent alcohol use. DESIGN: Cross-sectional data was collected across 30 randomly selected Australian communities stratified to represent a range of socio-economic and regional variation. SETTING: Data were collected during school time from adolescents attending a broad range of schools. PARTICIPANTS: The sample consisted of a combined 8256 students (aged 10-14 years). MEASUREMENTS: Students completed a web-based survey as part of the Healthy Neighbourhoods project. FINDINGS: Family management-which included practices such as parental monitoring and family rules about alcohol use-had the strongest and most consistent relationship with alcohol use in early adolescence. Adolescents reporting higher family management were less likely to have drunk alcohol in their life-time, less likely to drink alcohol in the preceding 30 days and less likely to have had an alcohol binge. Adolescents reporting emotionally close relationships with their fathers were less likely to have drunk alcohol in their life-time and less likely to have had an alcohol binge in the preceding fortnight. CONCLUSIONS: Findings indicate that family management practices may contribute to alcohol abstinence in adolescents. Furthermore, emotionally close father-adolescent relationships may also foster abstinence; however, fathers' drinking behaviours need to be considered.

Gender differences in personal, social and environmental influences on active travel to and from school for Australian adolescents.

Active travel (walking or cycling for transport) is an important contributor to adolescents overall physical activity (PA). This study examines associations between personal, social and environmental variables and active travel to and from school using data from a large observational study to examine active travel in 2961 year 6 and 8 students (48.7% male), aged 10-14 years (M=11.4, SD=0.8yrs) from 231 schools. Participants completed an on-line survey and all reported living within 2km of school. Data collected included mode of travel to and from school, self-reported health, and PA variables. Social environmental variables included having playgrounds, parks or gyms close by, feeling safe to walk alone, barriers to walking in the neighbourhood (e.g. traffic, no footpaths), peer and family support for PA, existence of sports teams/scout groups, community disorder and perceived neighbourhood safety. Results showed that while more girls (44.3%) than boys (37.4%) walked to school, lower proportions rode bikes (8.3% vs 22.4%) and hence fewer were active travellers overall. Logistic regression models, adjusted for age, location and socio-economic status were conducted for active travel to/from school, separately for boys and girls. Predictors for boys and girls being 'active travellers' to/from school included recreational facilities close to home, higher perceived safety of the neighbourhood and higher community disorder. For boys, social support from friends, scout groups available and higher enjoyment of physical activity was also important. These findings suggest areas for future research and may be used to guide strategies to increase active travel to and from school.

Associations between diet quality and depressed mood in adolescents: results from the Australian Healthy Neighbourhoods Study.

OBJECTIVE: Adolescence frequently coincides with the onset of psychiatric illness and depression is commonly observed in adolescents. Recent data suggest a role for diet quality in adult depression. Given the importance of adequate nutrition for brain development, it is of interest to examine whether diet quality is also related to depression in adolescents. METHODS: The study examined 7114 adolescents, aged 10-14 years, who participated in the Australian Healthy Neighbourhoods Study. Healthy and unhealthy diet quality scores were derived from a dietary questionnaire. The Short Mood and Feelings Questionnaire for adolescents measured depression. Adjustments were made for age, gender, socioeconomic status, parental education, parental work status, family conflict, poor family management, dieting behaviours, body mass index, physical activity, and smoking. RESULTS: Compared to the lowest category of the healthy diet score, the adjusted odds ratios (95% confidence interval) for symptomatic depression across categories (C) was: C2 = 0.61 (0.45-0.84); C3 = 0.58 (0.43-0.79); C4 = 0.47 (0.35-0.64); and C5 = 0.55 (0.40-0.77). Compared to the lowest quintile, the adjusted odds ratios (95% confidence interval) for symptomatic depression across increasing quintiles of the unhealthy diet score were: Q2 = 1.03 (0.87-1.22); Q3 = 1.22 (1.03-1.44); Q4 = 1.29 (1.12-1.50); and Q5 = 1.79 (1.52-2.11). CONCLUSIONS: Our results demonstrate an association between diet quality and adolescent depression that exists over and above the influence of socioeconomic, family, and other potential confounding factors.

Habitual active transport moderates the association of TV viewing time with body mass index.

BACKGROUND: Television viewing time is associated with obesity risk independent of leisure-time physical activity (LTPA). However, it is unknown whether the relationship of TV viewing time with body mass index (BMI) is moderated by other domains of physical activity. METHODS: A mail survey collected height; weight; TV viewing time; physical activity for transportation (habitual transport behavior; past week walking and bicycling), for recreation (LTPA), and in workplace; and sociodemographic variables in Adelaide, Australia. General linear models examined whether physical activity domains moderate the association between BMI and TV viewing time. RESULTS: Analysis of the sample (N = 1408) found that TV time, habitual transport, and LTPA were independently associated with participant's BMI. The interaction between TV time and habitual transport with BMI was significant, while that between TV time and LTPA was not. Subgroup analyses found that adjusted mean BMI was significantly higher for the high TV viewing category, compared with the low category, among participants who were inactive and occasionally active in transport, but not among those who were regularly active. CONCLUSIONS: Habitual active transport appeared to moderate the relationship between TV viewing time and BMI. Obesity risk associated with prolonged TV viewing may be mitigated by regular active transport.

Bicycle use for transport in an Australian and a Belgian city: associations with built-environment attributes.

The walkability attributes of neighborhood environments (residential density, land use mixture, and connectedness of streets) have been found to be associated with higher rates of walking. However, relatively less is known about the associations of walkability attributes with bicycle use for transport. We examined the relationships between adults' bicycle use for transport and measures of neighborhood walkability in two settings: an Australian city (Adelaide) with low rates of bicycle use and a Belgian city (Ghent) with high rates of bicycle use. A total of 2,159 and 382 participants were recruited in Adelaide and Ghent, respectively. A walkability index was derived from objectively measured data in Adelaide, while a similar index was derived from perceived measures in Ghent. Logistic regression models were employed to examine associations of bicycle use with different levels of walkability. There were higher rates of bicycle ownership for Ghent compared to Adelaide participants (96% versus 61%), and there was a higher prevalence of bicycle use for transport for Ghent compared to Adelaide participants (50% vs. 14%). Despite the large differences in bicycle ownership and use, living in a high-walkable neighborhood was associated with significantly higher odds of bicycle use for transport in both cities, after adjusting for relevant confounding factors. Built-environment innovations that are increasingly being advocated by health authorities and transport planners, primarily to promote higher rates of walking for transport, should also impact positively on bicycle use.

Associations of residential density with adolescents' physical activity in a rapidly urbanizing area of Mainland China.

In the context of recent social and economic transitions in China, lack of physical activity among adolescents is an emerging health risk, particularly so in rapidly expanding urban areas. Evidence from Western countries suggests that built environment attributes can influence the physical activity participation of young people, but whether or not this is the case for China is unknown. We recruited high school students from ten urban districts in Nanjing, Mainland China (n = 2,375; mean age = 13.9 +/- 1.0 years old; 46% boys; survey response rate = 89%). The outcome variable was self-reported recreational physical activity time; the primary explanatory variable was the residential density of the urban districts. Analysis was conducted using mixed-effects logistic regression models. After adjustment for potential confounding variables, including sedentary behavior and green space, there was a consistent and graduated association between residential density and physical activity; residential density was significantly negatively associated with recreational physical activity time for students from the higher tertile of residential density (OR; 95% CI = 0.64; 0.42 to 0.97) compared to those from the lower tertile. The direction and magnitude of the negative association between residential density and physical activity was similar for boys and girls. It should be a public health priority to identify the particular urban environment attributes that can encourage and support young people's participation in physical activity.