Jason Gilliland

The Influence of Local Food Environments on Adolescents’ Food Purchasing Behaviors

This study examined the relationship between the neighborhood food environment and the food purchasing behaviors among adolescents. Grade 7 and 8 students (n = 810) at 21 elementary schools in London, Ontario, Canada completed a questionnaire assessing their food purchasing behaviors. Parents of participants also completed a brief questionnaire providing residential address and demographic information. A Geographic Information System (GIS) was used to assess students’ home and school neighborhood food environment and land use characteristics. Logistic regression analysis was conducted to assess the influence of the home neighborhood food environment on students’ food purchasing behaviors, while two-level Hierarchical Non-Linear Regression Models were used to examine the effects of school neighborhood food environment factors on students’ food purchasing behaviors. The study showed that approximately 65% of participants reported self-purchasing foods from fast-food outlets or convenience stores. Close proximity (i.e., less than 1 km) to the nearest fast-food outlet or convenience store in the home neighborhood increased the likelihood of food purchasing from these food establishments at least once per week by adolescents (p < 0.05). High fast-food outlet density in both home and school neighborhoods was associated with increased fast-food purchasing by adolescents (i.e., at least once per week; p < 0.05). In conclusion, macro-level regulations and policies are required to amend the health-detracting neighborhood food environment surrounding children and youth’s home and school.

Route-Based Analysis to Capture the Environmental Influences on a Child's Mode of Travel between Home and School

This study examined environmental influences on a childs mode of travel between home and school. Grade 7 and 8 students (n = 614) from twenty-one schools throughout London, Ontario, participated in a school-based travel mode survey. Geographic information systems (GIS) were employed to examine environmental characteristics of the childs mode of travel between home and school measured at the scale of the likely travel route. Logistic regression was used to assess what factors influence both the to- and from-school trip. Over 62 percent of students living within 1.6 kilometers (1 mile) of school walked or biked to school and 72 percent walked or biked home from school. Actively commuting to school was positively associated with shorter trips, with distance being the most important correlate. Boys were significantly more likely to use active travel modes than girls. Higher traffic volume along the route was negatively related to rates of active travel and children from higher income neighborhoods were less likely to actively travel than children from lower income neighborhoods. In terms of environmental characteristics, the presence of street trees was positively associated and higher residential densities and mixed land uses were negatively associated with active travel to school. For the journey home, crossing major streets and increased intersection density were negatively associated with active travel. The findings of this research give evidence that active travel is associated with the environmental characteristics of walking routes. This information should be considered for urban planning and school planning purposes to improve childrens walking environments.

A Food Retail-Based Intervention on Food Security and Consumption

The effect of the built environment on diet (and ensuing health outcomes) is less understood than the effect of diet on obesity. Natural experiments are increasingly advocated in place of cross-sectional studies unable to suggest causality. The central research question of this paper, therefore, asks whether a neighborhood-level food retail intervention will affect dietary habits or food security. The intervention did not have a significant impact on fruit and vegetable consumption, and the intervention population actually purchased prepared meals more frequently. More problematic, only 8% of respondents overall regularly consumed enough fruits and vegetables, and 34% were food insecure. Further complicating this public health issue, the new grocery store closed after 17 months of operation. Results indicate that geographic access to food is only one element of malnutrition, and that multi-pronged dietary interventions may be more effective. The economic failure of the store also suggests the importance of non-retail interventions to combat malnutrition.

Hip fracture types in men and women change differently with age.

BackgroundHip fractures are expensive and a frequent cause of morbidity and mortality in the elderly. In most studies hip fractures have been viewed as a unitary fracture but recently the two main types of fracture (intertrochanteric and subcapital) have been viewed as two fractures with a different etiology and requiring a different approach to prevention. The relative proportion of intertrochanteric fractures increases with age in women. In previous studies no particular pattern in men has been noted. In this study, we explored changes in the relative proportion of the two fracture types with age in the two genders.MethodsPatients of 50 years and older, with a diagnosis of hip fracture, discharged from two local acute care hospitals over a 5 year period (n = 2150) were analyzed as a function of age and gender to explore the relative proportions of intertrochanteric and subcapital fractures, and the change in relative proportion in the two genders with age.ResultsOverall, for the genders combined, the proportion of intertrochanteric fractures increases with age (p = .007). In women this increase is significant (p < .001), but in men the opposite pattern is observed, with the proportion of intertrochanteric fractures falling significantly with age (p = .025).ConclusionsThe pattern of hip fractures is different in men and women with aging. It is likely that the pattern difference reflects differences in type and rate of bone loss in the genders, but it is conjectured that the changing rate and pattern of falling with increasing age may also be important. The two main hip fracture types should be considered distinct and different and be studied separately in studies of cause and prevention.

Quantifying the magnitude of environmental exposure misclassification when using imprecise address proxies in public health research.

In spatial epidemiologic and public health research it is common to use spatially aggregated units such as centroids of postal/zip codes, census tracts, dissemination areas, blocks or block groups as proxies for sample unit locations. Few studies, however, address the potential problems associated with using these units as address proxies. The purpose of this study is to quantify the magnitude of distance errors and accessibility misclassification that result from using several commonly-used address proxies in public health research. The impact of these positional discrepancies for spatial epidemiology is illustrated by examining misclassification of accessibility to several health-related facilities, including hospitals, public recreation spaces, schools, grocery stores, and junk food retailers throughout the City of London and Middlesex County, Ontario, Canada. Positional errors are quantified by multiple neighborhood types, revealing that address proxies are most problematic when used to represent residential locations in small towns and rural areas compared to suburban and urban areas. Findings indicate that the shorter the threshold distance used to measure accessibility between subject population and health-related facility, the greater the proportion of misclassified addresses. Using address proxies based on large aggregated units such as centroids of census tracts or dissemination areas can result in very large positional discrepancies (median errors up to 343 and 2088 m in urban and rural areas, respectively), and therefore should be avoided in spatial epidemiologic research. Even smaller, commonly-used, proxies for residential address such as postal code centroids can have large positional discrepancies (median errors up to 109 and 1363 m in urban and rural areas, respectively), and are prone to misrepresenting accessibility in small towns and rural Canada; therefore, postal codes should only be used with caution in spatial epidemiologic research.

An epidemiologic profile of pediatric concussions: identifying urban and rural differences.

BACKGROUND The objective of this study was to describe the epidemiology of concussions presenting to the emergency department (ED). METHODS A retrospective cohort of concussions for pediatric (age < 18 years) patients treated in the ED of a regional pediatric Level 1 trauma center from 2006 to 2011 was examined. Descriptive and geographic analyses were completed, with comparisons by age groups and residence (urban/rural). RESULTS There were a total of 2,112 treated pediatric concussions. Two thirds of the concussions occurred in males (67%), with a median age of 13 years (interquartile range [IQR], 6). Nearly half of the pediatric concussions were sports related (48%); 36% of these concussions were from hockey. Significant differences were found in the distribution of the mechanism of injury across age groups (p < 0.001). Falls were most prevalent among young children, and sports concussions, for children 10 years and older. Two fifths of concussions occurred during winter months. Discharge disposition significantly differed by age (p < 0.001), with home discharge increasing with age up to 14 years. There were a total of 387 rural (19%) and 1,687 urban (81%) concussed patients, for a mean ED concussion visit rate of 2.2 per 1,000 and 3.5 per 1,000, respectively. Rural patients were older (14 [IQR, 6] vs. 13 [IQR, 6], p = 0.019] and sustained 2.5 times more concussions from a motor vehicle crash compared with urban youth patients (p < 0.001). CONCLUSION Males in early adolescence are at highest risk for concussion, particularly from sport-related activities. Urban and rural children have differences in their etiology and severity of concussions. Concussions are predictable, and their prevention should be targeted based on epidemiologic and environmental data. LEVEL OF EVIDENCE Epidemiologic, study, level III.

Community Development and the Influence of New Food Retail Sources on the Price and Availability of Nutritious Food

ABSTRACT: Studies have demonstrated links between the accessibility of food and multiple health outcomes. Policymakers engaged in local community development may use public health concerns as a strategy to procure funding for food retail initiatives. Few studies to date have demonstrated the impact that a new food retailer can have on geographic and economic access to nutritious food in a community, evidence which could support the case for new food retail. This paper examines the price and availability of food before and after the opening of two new grocery stores in a former food desert in Flint, Michigan. The results indicate a substantial improvement in both geographic and economic food accessibility, and show no statistical difference between prices at average grocery stores and the new stores. Discussion suggests that investment in poorer neighborhoods can be beneficial to the local population and the community at large by creating a local multiplier effect through increased spending in the community.

Free Range Kids? Using GPS-Derived Activity Spaces to Examine Children’s Neighborhood Activity and Mobility

This study examines the neighborhood activity spaces (NAS) of 9- to 13-year-old children (n = 143) from seven schools in London, Canada. Data from Global Positioning System (GPS) loggers worn for 7 days were used to isolate and test measures for children’s pedestrian-based neighborhood activity: the maximum distance traveled from home and relative time spent in neighborhood settings. Descriptive and linear regression analyses examined the influence of individual, perceptual, and environmental factors on neighborhood use and travel. Participants spent a large portion of their out-of-school time (75%) in their NAS. Although traveling far from home on occasion, 94.5% of children’s time on average was spent within a short distance of home; participants spent little of their free time in broader neighborhood settings. School travel mode and independent mobility were among the strongest predictors of both distance traveled and time spent close to home. Perceptions of neighborhood safety, neighborhood type, and nearby land uses also influenced local activity.

The effect of physical activity on adult obesity: Evidence from the Canadian NPHS panel

Although physical activity has been considered as an important modifiable risk factor for obesity, the empirical evidence on the relationship between physical activity and obesity is mixed. Observational studies in the public health literature fail to account for time-invariant unobserved heterogeneity and dynamics of weight, leading to biased estimation of the effect of physical activity on obesity. To overcome this limitation, we propose dynamic fixed-effects models to account for unobserved heterogeneity bias and the dynamics of obesity. We use nationally representative longitudinal data on the cohort of adults aged 18-50 years in 1994/95 from Canadas National Population Health Survey and followed them over 16 years. Obesity is measured by BMI (body mass index). After controlling for a wide range of socio-economic factors, the impact of four alternative measures of leisure-time physical activity (LTPA) and work-related physical activity (WRPA) are analyzed. The results show that each measure of LTPA exerts a negative effect on BMI and the effects are larger for females. Our key results show that participation in LTPA exceeding 1.5 kcal/kg per day (i.e., at least 30 min of walking) reduces BMI by about 0.11-0.14 points in males and 0.20 points in females relative to physically inactive counterparts. Compared to those who are inactive at workplace, being able to stand or walk at work is associated with a reduction in BMI in the range of 0.16-0.19 points in males and 0.24-0.28 points in females. Lifting loads at workplace is associated with a reduction in BMI by 0.2-0.3 points in males and 0.3-0.4 points in females relative to those who are reported sedentary. Policies aimed at promotion of LTPA combined with WRPA like walking or climbing stairs daily would help reduce adult obesity risks.

Association between neighbourhood fast-food and full-service restaurant density and body mass index: A cross-sectional study of Canadian adults

Objective: Frequent fast-food consumption is a well-known risk factor for obesity. This study sought to determine whether the availability of fast-food restaurants has an influence on body mass index (BMI).METHODS: BMI and individual-level confounding variables were obtained from the 2007-08 Canadian Community Health Survey. Neighbourhood socio-demographic variables were acquired from the 2006 Canadian Census. The geographic locations of all restaurants in Canada were assembled from a validated business registry database. The density of fast-food, full-service and non-chain restaurants per 10,000 individuals was calculated for respondents’ forward sortation area. Multivariable regression analyses were conducted to analyze the association between restaurant density and BMI.RESULTS: Fast-food, full-service and non-chain restaurant density variables were statistically significantly associated with BMI. Fast-food density had a positive association whereas full-service and non-chain restaurant density had a negative association with BMI (additional 10 fast-food restaurants per capita corresponded to a weight increase of 1 kilogram; p<0.001). These associations were primarily found in Canada’s major urban jurisdictions.CONCLUSIONS: This research was the first to investigate the influence of fast-food and full-service restaurant density on BMI using individual-level data from a nationally representative Canadian survey. The finding of a positive association between fast-food restaurant density and BMI suggests that interventions aiming to restrict the availability of fast-food restaurants in local neighbourhoods may be a useful obesity prevention strategy.RésuméOBJECTIF: La consommation fréquente d’aliments de restauration rapide est un facteur de risque d’obésité bien connu. Nous avons cherché à déterminer si la présence de restaurants rapides a une influence sur l’indice de masse corporelle (IMC).MÉTHODE: L’IMC et les variables de confusion individuelles ont été puisés dans l’Enquête sur la santé dans les collectivités canadiennes de 2007-2008. Les variables sociodémographiques par quartier ont été obtenues dans le Recensement du Canada de 2006. Nous avons déterminé l’emplacement géographique de tous les restaurants au Canada à partir d’un registre des entreprises validé. Nous avons calculé la densité pout 10 000 habitants des restaurants rapides, plein service et n’appartenant pas à une chaîne, selon la région de tri d’acheminement des répondants. Nous avons effectué des analyses de régression multivariées pour étudier l’association entre la densité des restaurants et l’IMC.RÉSULTATS: Les variables de densité des restaurants rapides, plein service et n’appartenant pas à une chaîne présentaient une corrélation significative avec l’IMC. Pour la densité des restaurants rapides, cette association était positive, tandis que pour les restaurants plein service et n’appartenant pas à une chaîne, la densité était négativement associée à l’IMC (chaque tranche supplémentaire de 10 restaurants rapides par habitant correspondait à une hausse pondérale d’1 kilogramme; p<0,001). Ces associations étaient principalement observées dans les grands centres urbains du Canada.CONCLUSIONS: Notre étude est la première à analyser l’influence de la densité des restaurants rapides et plein service sur l’IMC à l’aide de données individuelles provenant d’une enquête nationale représentative menée au Canada. La découverte d’une association positive entre la densité des restaurants rapides et l’IMC donne à penser que les interventions visant à limiter la présence des restaurants rapides à l’échelle des quartiers pourraient être des stratégies utiles pour prévenir l’obésité.