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Background: Descriptive norms (what other people do) relate to individual-level dietary behaviour and health outcome including overweight and obesity. Descriptive norms vary across residential areas but the impact of spatial variation in norms on individual-level diet and health is poorly understood. This study assessed spatial associations between local descriptive norms for overweight/obesity and insufficient fruit intake (spatially-specific local prevalence), and individual-level dietary intakes (fruit, vegetable and sugary drinks) and 10-year change in body mass index (BMI) and glycosylated haemoglobin (HbA 1c )., Methods: HbA 1c and BMI were clinically measured three times over 10 years for a population-based adult cohort (n = 4056) in Adelaide, South Australia. Local descriptive norms for both overweight/obesity and insufficient fruit intake specific to each cohort participant were calculated as the prevalence of these factors, constructed from geocoded population surveillance data aggregated for 1600 m road-network buffers centred on cohort participants' residential addresses. Latent growth models estimated the effect of local descriptive norms on dietary behaviours and change in HbA 1c and BMI, accounting for spatial clustering and covariates (individual-level age, sex, smoking status, employment and education, and area-level median household income)., Results: Local descriptive overweight/obesity norms were associated with individual-level fruit intake (inversely) and sugary drink consumption (positively), and worsening HbA 1c and BMI. Spatially-specific local norms for insufficient fruit intake were associated with individual-level fruit intake (inversely) and sugary drink consumption (positively) and worsening HbA 1c but not change in BMI. Individual-level fruit and vegetable intakes were not associated with change in HbA 1c or BMI. Sugary drink consumption was also not associated with change in HbA 1c but rather with increasing BMI., Conclusion: Adverse local descriptive norms for overweight/obesity and insufficient fruit intake are associated with unhealthful dietary intakes and worsening HbA 1c and BMI. As such, spatial variation in lifestyle-related norms is an important consideration relevant to the design of population health interventions. Adverse local norms influence health behaviours and outcomes and stand to inhibit the effectiveness of traditional intervention efforts not spatially tailored to local population characteristics. Spatially targeted social de-normalisation strategies for regions with high levels of unhealthful norms may hold promise in concert with individual, environmental and policy intervention approaches.

Objective: This study sought to assess whether changes in depressive symptoms, general health, and area-level socio-economic status (SES) were associated to changes over time in waist circumference and body mass index (BMI). Methods: A total of 2871 adults (18 years or older), living in Adelaide (South Australia), were observed across three waves of data collection spanning ten years, with clinical measures of waist circumference, height and weight. Participants completed the Centre for Epidemiologic Studies Depression (CES-D) and Short Form 36 health questionnaires (SF-36 general health domain). An area-level SES measure, relative location factor, was derived from hedonic regression models using residential property features but blind to location. Growth curve models with latent variables were fitted to data. Results: Waist circumference, BMI and depressive symptoms increased over time. General health and relative location factor decreased. Worsening general health and depressive symptoms predicted worsening waist circumference and BMI trajectories in covariate-adjusted models. Diminishing relative location factor was negatively associated with waist circumference and BMI trajectories in unadjusted models only. Conclusions: Worsening depressive symptoms and general health predict increasing adiposity and suggest the development of unhealthful adiposity might be prevented by attention to negative changes in mental health and overall general health. [ABSTRACT FROM AUTHOR]

Consistent associations have been observed between macro-level urban sprawl and overweight/obesity, but whether residential proximity to urban centres predicts adiposity change over time has not been established. Further, studies of local-area walkability and overweight/obesity have generated mixed results. This study examined 4-year change in adults' waist circumference in relation to proximity to city centre, proximity to closest suburban centre, and local-area walkability. Data were from adult participants (n=2080) of a cohort study on chronic conditions and health risk factors in Adelaide, Australia. Baseline data were collected in 2000-03 with a follow-up in 2005-06. Multilevel regression models examined in 2015 the independent and joint associations of the three environmental measures with change in waist circumference, accounting for socio-demographic covariates. On average, waist circumference rose by 1.8cm over approximately 4years. Greater distance to city centre was associated with a greater increase in waist circumference. Participants living in distal areas (20km or further from city centre) had a greater increase in waist circumference (mean increase: 2.4cm) compared to those in proximal areas (9km or less, mean increase: 1.2cm). Counterintuitively, living in the vicinity of a suburban centre was associated with a greater increase in adiposity. Local-area walkability was not significantly associated with the outcome. Residential proximity to city centre appears to be protective against excessive increases in waist circumference. Controlled development and targeted interventions in the urban fringe may be needed to tackle obesity. Additional research needs to assess behaviours that mediate relationships between sprawl and obesity. [ABSTRACT FROM AUTHOR]

Although 49% of Australian residents have at least one overseas-born parent, little is known about children's longitudinal bodyweight transitions among the migrant population. This study examines the net associations between maternal region-of-birth and children's longitudinal bodyweight transitions between underweight, normal, and overweight/obese status from ages 2 to 17 years. A sample of 8889 children was drawn from seven waves of a national population-based cohort study, the Longitudinal Study of Australian Children, conducted between 2004 and 2016. A multistate approach was used to investigate (i) the net effect of mother's region-of-birth on children's bodyweight transitions, (ii) the net estimation of cumulative transition probabilities, and (ii) the net conditional bodyweight expectancy, controlling for child-, family-, and neighbourhood-factors associated with children's bodyweight. Our results showed children of Oceania and African mothers had unfavourable outcomes (i.e., lower remission from or higher incidence of underweight or overweight/obese status) than children of non-migrants. Toddlers with suboptimal bodyweight status (especially those from disadvantaged groups) had higher net cumulative probabilities of staying in that status as a 17-year-old adolescent unless they managed to transfer to normal weight in the primary school years. The 15-year bodyweight expectancy depended on the initial bodyweight status at age two years, with some children of migrant mothers affected longer by suboptimal bodyweight status. In Australia, region-of-birth related disparities in bodyweight started early and were of significant duration throughout development until late adolescence. Culturally tailored health programs should begin at least as early as two years of age. [ABSTRACT FROM AUTHOR]

Descriptive norms vary between places. Spatial variation in health-related descriptive norms may predict individual-level health outcomes. Such relationships have rarely been investigated. This study assessed 10-year change in glycosylated haemoglobin (HbA 1c ) in relation to local descriptive norms for overweight/obesity (n = 1890) and physical inactivity (n = 1906) in models accounting for features of the built environment. HbA 1c was measured three times over 10 years for a population-based biomedical cohort of adults in Adelaide, South Australia. Environmental exposures were expressed for cohort participants using 1600 m road-network buffers centred on participants' residential address. Local descriptive norms (prevalence of overweight/obesity [body mass index ≥25 kg/m 2 ] and of physical inactivity [<150 min/week]) were aggregated from responses to a separate geocoded population survey. Built environment measures were public open space (POS) availability (proportion of buffer area) and walkability. Separate sets of multilevel models analysed different predictors of 10-year change in HbA 1c . Each model featured one local descriptive norm and one built environment variable with area-level education and individual-level covariates (age, sex, employment status, education, marital status, and smoking status). Interactions between local descriptive norms and built environment measures were assessed. HbA 1c increased over time. POS availability and local descriptive norms for overweight/obesity and physical inactivity were each associated with greater rates of HbA 1c increase. Greater walkability was associated with a reduced rate of HbA 1c increase, and reduced the influence of the overweight/obesity norm on the rate of increase in HbA 1c . Local descriptive health-related norms and features of the built environment predict 10-year change in HbA 1c . The impact of local descriptive norms can vary according to built environment features. Little researched thus far, local descriptive norms may play an important role in the evolution of HbA 1c and thus cardiometabolic risk, over time. Further empirical research on local descriptive norms is necessary to understand how residential environments shape chronic disease risk. [ABSTRACT FROM AUTHOR]