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Background and aims Bicycling may be less appealing in parts of the world where cycling is less safe. Differences between jurisdictions suggest route design is key to improving safety and increasing ridership. Previous studies faced difficulties in effectively assessing denominators for risk calculations and controlling confounding. This paper describes the advantages of the case-crossover design of the Bicyclists' Injuries and the Cycling Environment study to address these challenges to observational studies of cycling safety. Methods Injured cyclists were recruited from the emergency departments of five hospitals in Vancouver and Toronto, Canada. In 18 months, 690 participants were successfully recruited and interviewed. Each participant was interviewed to map the route of their injury trip, identify the injury site and select two control sites at random from the same route. Infrastructural characteristics at each study site were scored by site observers who were blinded as to whether sites were crash or comparison sites. Analyses will compare infrastructural variables between case and control sites with conditional logistic regression. Discussion This study presents a novel application of the case-crossover design to the evaluation of relationships between infrastructure and cycling safety while controlling confounders and exposure to risk. It is hoped that the value of this method and the efficiency of the recruitment process will encourage replication in other locations, to expand the range of cycling infrastructure compared and to facilitate evidence-based cycling infrastructure choices that can make cycling safer and more appealing. [ABSTRACT FROM AUTHOR]

Background Characteristics of social environments are potential risk factors for adolescent injury. Impacts of social capital on the occurrence of such injuries have rarely been explored. Methods General health questionnaires were completed by 8910 youth aged 14 years and older as part of the 2010 Canadian Health Behaviour in School- Aged Children study. These were supplemented with community-level data from the 2006 Canada Census of Population. Multilevel logistic regression models with random intercepts were fit to examine associations of interest. The reliability and validity of variables used in this analysis had been established in past studies, or in new analyses that employed factor analysis. Results Between school differences explained 2% of the variance in the occurrence of injuries. After adjustment for all confounders, community social capital did not have any impact on the occurrence of injuries in boys: OR: 1.01, 95% CI 0.80 to 1.29. However, living in areas with low social capital was associated with lower occurrence of injuries in girls (OR 0.78, 95% CI 0.63 to 0.96). Other factors that were significantly related to injuries in both genders were younger age, engagement in more risky behaviours, and negative behavioural influences from peers. Conclusions After simultaneously taking into account the influence of community-level and individual-level factors, community levels of social capital remained a relatively strong predictor of injury among girls but not boys. Such gender effects provide important clues into the social aetiology of youth injury. [ABSTRACT FROM AUTHOR]

Objective To assess the perceived effectiveness of cigarette health warnings in China, compared with picture and text-only warnings from other countries. Method 1169 individuals (adult smokers, adult nonsmokers and youth) from four Chinese cities (Beijing, Shanghai, Kunming and Yinchuan) viewed 10 health warnings on cigarette packages, which included (a) the current Chinese text warnings covering 30% of the front/back of the pack (introduced October 2008); (b) the former Chinese text warning located on the side of the pack; (c) four picture warnings covering 50% of the front/back of the pack from Canada (lung cancer), Singapore (mouth disease), Hong Kong (gangrene) and European Union (clogged arteries); and (d) the same four warnings without the picture. Participants rated and ranked the 10 warnings on dimensions including how effective each would be in motivating smokers to quit and in convincing youth not to start smoking. Results Both Chinese warnings were consistently rated as least effective, with the new Chinese warning rated only slightly higher than the old warning. The picture warnings were consistently ranked or rated as most effective, with the text-only versions in the middle. Results were consistent across subject group, city and sex. Conclusions (1) Picture warnings are rated as much more effective than the same warnings without pictures. (2) The revised health warnings in China, introduced in October 2008, are only marginally more effective than the previous warning and far less effective than even text warnings from other countries. These results, coupled with population-based evaluation studies, suggest that pictorial warnings would significantly increase the impact of health warnings in China. [ABSTRACT FROM PUBLISHER]

Background This study sought to examine the impact of cigarette packaging on young women, including the impact of 'plain' packaging. Methods Participants were randomised to view eight cigarette packs designed according to one of four experimental conditions: fully-branded female brands; the same brands without descriptors (eg, 'slims'); the same brands without brand imagery or descriptors (ie, 'plain' packs); and fully branded non-female brands as a control condition. Participants rated packs on perceived appeal, taste, tar, health risks and smoker 'traits'. Results Fully-branded female packs were rated as significantly more appealing than 'no descriptor' packs, 'plain' packs and non-female branded packs. Female branded packs were associated with a greater number of positive attributes including glamour, slimness and attractiveness, compared to brands without descriptors and 'plain' packs. Women who viewed plain packs were less likely to believe that smoking helps people control their appetite--an important predictor of smoking among young women--compared to women who viewed branded female packs. Conclusions 'Plain' packaging--removing colours and design elements--and removing descriptors such as 'slims' from packs may reduce brand appeal and thereby susceptibility to smoking among young women. [ABSTRACT FROM AUTHOR]

Background National estimates of the upcoming diabetes epidemic are needed to understand the distribution of diabetes risk in the population and to inform health policy. Objective To create and validate a population-based risk prediction tool for incident diabetes using commonly collected national survey data. Methods With the use of a cohort design that links baseline risk factors to a validated population-based diabetes registry, a model (Diabetes Population Risk Tool (DPoRT)) was developed to predict 9-year risk for diabetes. The probability of developing diabetes was modelled using sex-specific Weibull survival functions for people >20 years of age without diabetes (N=19 861). The model was validated in two external cohorts in Ontario (N=26 465) and Manitoba (N=9899). Predictive accuracy and model performance were assessed by comparing observed diabetes rates with predicted estimates. Discrimination and calibration were measured using a C statistic and Hosmer--Lemeshow X2 statistic (X2H-L). Results Predictive factors included were body mass index, age, ethnicity, hypertension, immigrant status, smoking, education status and heart disease. DPoRT showed good discrimination (C=0.77-0.80) and calibration (X2 H-L <20) in both external validation cohorts. Conclusions This algorithm can be used to estimate diabetes incidence and quantify the effect of interventions using routinely collected survey data. [ABSTRACT FROM AUTHOR]

Background The relationships of home and school environments, health risk behaviours and two sentinel adolescent health outcomes were examined in an aetiological analysis. The analysis focused on determinants of the health of young people and the role of school settings in the optimisation of health. Methods Records were examined from the Canadian sample of the Health Behaviour in School-aged Children (HBSC) Survey. 3402 young people in Ontario, Canada were administered this survey in 2006, of which 1966 were re-administered the survey 1 year later and supplied complete data. Individual items and factoranalytically derived scales were used to examine potential aetiological relationships in a series of structural equation models. Health outcomes examined were serious injury and psychosomatic symptoms. Models developed from cross-sectional data were confirmed longitudinally. Results Adolescents who reported negative home and school environments reported higher levels of substance use, psychosomatic symptoms and serious injuries (the latter identified in longitudinal analysis only). Engagement in health risk behaviour partially mediated the link between these two environments and the sentinel health outcomes. Positive school environments were protective in that they moderated associations between negative home environments and engagement in health risk behaviours. The effects observed in longitudinal analyses were generally consistent with those observed crosssectionally. Conclusions Negative home environments clearly place adolescents at risk for engagement in health risk behaviours and associated physical health outcomes. Positive school environments can in part moderate these relationships. Optimisation of school social environments therefore remains warranted as a population health strategy. [ABSTRACT FROM AUTHOR]

Background It has been hypothesised that dehydration in infancy could permanently increase sodium retention, raising blood pressure in later life. In this study, the association between gastrointestinal tract infection in infancy, a clinically relevant exposure often accompanied by dehydration, and raised blood pressure in childhood was investigated. Methods Data from a cohort study nested within a cluster-randomised trial of breastfeeding promotion in the Republic of Belarus were analysed. 17 046 healthy breastfed infants were enrolled from 31 maternity hospitals. 13 889 (81.5%) children were followed-up at 6.5 years. Exposure measures were any gastrointestinal infection in infancy (to 1 year) and hospitalisations for gastrointestinal infection in infancy and in childhood (1-6.5 years). The outcomes were systolic and diastolic blood pressure at age 6.5 years. Results The prevalence of any gastrointestinal infection in infancy, and of hospitalisation for gastrointestinal infection in infancy or childhood, was 11.4%, 3.2% and 6.0%, respectively. No associations were observed between systolic blood pressure and any gastrointestinal infection (mean difference in those with minus those without infection -0.04 mm Hg; 95% CI -0.52 to 0.43) or hospitalisation for gastrointestinal infection (difference=-0.22 mm Hg; -1.07 to 0.64) in infancy. Nor were associations observed between diastolic blood pressure and any gastrointestinal infection during infancy or hospitalisation for gastrointestinal infection during infancy or childhood. Conclusion No evidence was found to prove that hospitalisation for gastrointestinal infection in infancy or childhood leads to raised blood pressure at age 6.5 years in a developed country setting. [ABSTRACT FROM AUTHOR]

Objectives Parental supervision reduces young children's risk of unintentional injuries, but supervision by older siblings has been shown to increase risk. The current study explored how this differential risk of injury may arise. Methods The supervision behaviours of mothers were compared to those of their older children when each was the designated supervisor of a young child in their family in a setting having 'contrived hazards'. Results Mothers engaged in more proactive safety behaviours by removing hazards, whereas older siblings more often modelled injury-risk behaviours by interacting with hazards, and supervisees were likely to interact with hazards the older sibling touched. Supervisees displayed more injury-risk behaviours when supervised by a sibling, yet sibling supervisors were less attentive to supervisee risk behaviours than mothers. Supervisees also were more non-compliant with older siblings than mothers when requested to stop risk taking. Conclusions Both supervisor and supervisee behaviour patterns contribute to increase the risk of injury when older siblings supervise younger ones. [ABSTRACT FROM AUTHOR]