Romain Casey

Measuring the food environment using geographical information systems: a methodological review.

OBJECTIVE Through a literature review, we investigated the geographic information systems (GIS) methods used to define the food environment and the types of spatial measurements they generate. DESIGN Review study. SETTING Searches were conducted in health science databases, including Medline/Pubmed, PsycINFO, Francis and GeoBase. We included studies using GIS-based measures of the food environment published up to 1 June 2008. RESULTS Twenty-nine papers were included. Two different spatial approaches were identified. The density approach quantifies the availability of food outlets using the buffer method, kernel density estimation or spatial clustering. The proximity approach assesses the distance to food outlets by measuring distances or travel times. GIS network analysis tools enable the modelling of travel time between referent addresses (home) and food outlets for a given transportation network and mode, and the assumption of travel routing behaviours. Numerous studies combined both approaches to compare food outlet spatial accessibility between different types of neighbourhoods or to investigate relationships between characteristics of the food environment and individual food behaviour. CONCLUSIONS GIS methods provide new approaches for assessing the food environment by modelling spatial accessibility to food outlets. On the basis of the available literature, it appears that only some GIS methods have been used, while other GIS methods combining availability and proximity, such as spatial interaction models, have not yet been applied to this field. Future research would also benefit from a combination of GIS methods with survey approaches to describe both spatial and social food outlet accessibility as important determinants of individual food behaviours.

Aquaporin-4 antibody–negative neuromyelitis optica Distinct assay sensitivity–dependent entity

Objective: To optimize aquaporin-4 (AQP4) antibody (Ab) detection and to assess the influence of the increased sensitivity of the assay on the demographic and disease-related characteristics of a group of AQP4-Ab–negative patients. Methods: Serum samples were obtained from patients included in the French NOMADMUS database with a definite diagnosis of neuromyelitis optica (NMO) (n = 87) and were compared with controls (n = 54). They were tested by indirect immunofluorescence and cell-based assays (CBAs) in various conditions and with several plasmids. Results: We identified the CBA on live cells transfected with the untagged AQP4-M23 isoform as the best method, with a sensitivity of 74.4% and a specificity of 100%. We demonstrated a direct relationship between improvement of the sensitivity of the detection method and the distinctiveness and characteristics of the AQP4-Ab–negative NMO group. Whereas with the classic indirect immunofluorescence or current AQP4-M1 CBA we found only slight differences between the 2 populations, using the AQP4-M23 CBA, we demonstrated that patients with AQP4-Ab–negative NMO expressed specific demographic and disease-related features. They were characterized by an equal male/female ratio (p < 0.001), a Caucasian ethnicity (p = 0.029), and an overrepresentation of simultaneous optic neuritis and transverse myelitis at first episode (p = 0.015). In terms of disability, they experienced a better visual acuity at last follow-up compared with seropositive NMO (p = 0.007). Conclusion: This raises the question of a distinct physiopathology for patients with AQP4-Ab–negative NMO and of their place in the spectrum of the disease.

Higher Serum Osteocalcin Is Associated With Lower Abdominal Aortic Calcification Progression and Longer 10-Year Survival in Elderly Men of the MINOS Cohort

CONTEXT Abdominal aortic calcification (AAC) is an indicator of cardiovascular risk, especially in the diseases characterized by insulin resistance such as type 2 diabetes. Osteocalcin is a bone-secreted hormone that favors insulin sensitivity and insulin secretion. OBJECTIVES We investigated whether total serum osteocalcin level at baseline is associated with AAC progression and 10-year all-cause mortality in elderly men. DESIGN AND PARTICIPANTS We assessed 774 men aged 51-85 years from the MINOS cohort who had osteocalcin measurement and lumbar spine radiographs at baseline. They were followed-up prospectively for 10 years. Among them, 615 patients had a follow-up radiograph at 3.5 or 7 years. MAIN OUTCOME MEASURES Serum total osteocalcin was measured with an immunoradiometric assay on morning fasting serum collected at baseline. Kauppilas AAC score was assessed from lumbar spine radiographs. AAC progression rate was calculated as the difference between AAC on the last available radiograph and AAC at baseline divided by the follow-up time. Death status was collected over 10 years. RESULTS In multivariate analysis, higher baseline total osteocalcin was associated with lower AAC progression rate (odds ratio = 0.74 [0.57-0.97] per 10 ng/mL variation; P = 0.029). At the 10-year follow-up, there were 599 men alive (77%), 181 dead (23%), and 2 lost to follow-up. Higher osteocalcin was associated with lower 10-year all-cause mortality (hazard ratio = 0.62 [0.44-0.86] per 10 ng/mL variation; P = 0.005). CONCLUSION Higher baseline total osteocalcin concentrations were associated with lower AAC progression rate and lower mortality. These data suggest that osteocalcin level might be an independent indicator of cardiovascular risk and global health in elderly Caucasian men.

Comparative efficacy of fingolimod vs natalizumab: A French multicenter observational study

Objective: To compare natalizumab and fingolimod on both clinical and MRI outcomes in patients with relapsing-remitting multiple sclerosis (RRMS) from 27 multiple sclerosis centers participating in the French follow-up cohort Observatoire of Multiple Sclerosis. Methods: Patients with RRMS included in the study were aged from 18 to 65 years with an Expanded Disability Status Scale score of 0–5.5 and an available brain MRI performed within the year before treatment initiation. The data were collected for 326 patients treated with natalizumab and 303 with fingolimod. The statistical analysis was performed using 2 different methods: logistic regression and propensity scores (inverse probability treatment weighting). Results: The confounder-adjusted proportion of patients with at least one relapse within the first and second year of treatment was lower in natalizumab-treated patients compared to the fingolimod group (21.1% vs 30.4% at first year, p = 0.0092; and 30.9% vs 41.7% at second year, p = 0.0059) and supported the trend observed in nonadjusted analysis (21.2% vs 27.1% at 1 year, p = 0.0775). Such statistically significant associations were also observed for gadolinium (Gd)-enhancing lesions and new T2 lesions at both 1 year (Gd-enhancing lesions: 9.3% vs 29.8%, p < 0.0001; new T2 lesions: 10.6% vs 29.6%, p < 0.0001) and 2 years (Gd-enhancing lesions: 9.1% vs 22.1%, p = 0.0025; new T2 lesions: 16.9% vs 34.1%, p = 0.0010) post treatment initiation. Conclusion: Taken together, these results suggest the superiority of natalizumab over fingolimod to prevent relapses and new T2 and Gd-enhancing lesions at 1 and 2 years. Classification of evidence: This study provides Class IV evidence that for patients with RRMS, natalizumab decreases the proportion of patients with at least one relapse within the first year of treatment compared to fingolimod.

Identifying built environmental patterns using cluster analysis and GIS: Relationships with walking, cycling and body mass index in French adults

BackgroundSocio-ecological models suggest that both individual and neighborhood characteristics contribute to facilitating health-enhancing behaviors such as physical activity. Few European studies have explored relationships between local built environmental characteristics, recreational walking and cycling and weight status in adults. The aim of this study was to identify built environmental patterns in a French urban context and to assess associations with recreational walking and cycling behaviors as performed by middle-aged adult residents.MethodsWe used a two-step procedure based on cluster analysis to identify built environmental patterns in the region surrounding Paris, France, using measures derived from Geographic Information Systems databases on green spaces, proximity facilities (destinations) and cycle paths. Individual data were obtained from participants in the SU.VI.MAX cohort; 1,309 participants residing in the Ile-de-France in 2007 were included in this analysis. Associations between built environment patterns, leisure walking/cycling data (h/week) and measured weight status were assessed using multinomial logistic regression with adjustment for individual and neighborhood characteristics.ResultsBased on accessibility to green spaces, proximity facilities and availability of cycle paths, seven built environmental patterns were identified. The geographic distribution of built environmental patterns in the Ile-de-France showed that a pattern characterized by poor spatial accessibility to green spaces and proximity facilities and an absence of cycle paths was found only in neighborhoods in the outer suburbs, whereas patterns characterized by better spatial accessibility to green spaces, proximity facilities and cycle paths were more evenly distributed across the region. Compared to the reference pattern (poor accessibility to green areas and facilities, absence of cycle paths), subjects residing in neighborhoods characterized by high accessibility to green areas and local facilities and by a high density of cycle paths were more likely to walk/cycle, after adjustment for individual and neighborhood sociodemographic characteristics (OR = 2.5 95%CI 1.4-4.6). Body mass index did not differ across patterns.ConclusionsBuilt environmental patterns were associated with walking and cycling among French adults. These analyses may be useful in determining urban and public health policies aimed at promoting a healthy lifestyle.

Investigating disparities in spatial accessibility to and characteristics of sport facilities: direction, strength, and spatial scale of associations with area income.

We conducted an environmental justice study of the spatial distribution of sport facilities, a major resource for physical activity, in the Paris Region in France. Comprehensive data of the French Census of Sport Facilities allowed us to investigate disparities not only in the spatial accessibility to facilities, but also in the characteristics of these facilities. We found that the associations between area income and the presence of facilities or favorable characteristics of these facilities varied from positive to negative depending on the facilities and on the characteristics examined. Sensitivity analyses defining area income in circular areas of different radii permitted a refined identification of areas underserved in sport facilities.

Spatial accessibility to physical activity facilities and to food outlets and overweight in French youth

Objective:Some characteristics of the built environment have been associated with obesity in youth. Our aim was to determine whether individual and environmental socio-economic characteristics modulate the relation between youth overweight and spatial accessibility to physical activity (PA) facilities and to food outlets.Design:Cross-sectional study.Subjects:3293 students, aged 12±0.6 years, randomly selected from eastern France middle schools.Measurements and methods:Using geographical information systems (GIS), spatial accessibility to PA facilities (urban and nature) was assessed using the distance to PA facilities at the municipality level; spatial accessibility to food outlets (general food outlets, bakeries and fast-food outlets) was calculated at individual level using the student home address and the food outlets addresses. Relations of weight status with spatial accessibility to PA facilities and to food outlets were analysed using mixed logistic models, testing potential direct and interaction effects of individual and environmental socio-economic characteristics.Results:Individual socio-economic status modulated the relation between spatial accessibility to PA facilities and to general food outlets and overweight. The likelihood of being overweight was higher when spatial accessibility to urban PA facilities and to general food outlets was low, but in children of blue-collar-workers only. The odds ratio (OR) (95% confidence interval) for being overweight of blue-collar-workers children compared with non-blue-collar-workers children was 1.76 (1.25–2.49) when spatial accessibility to urban PA facilities was low. This OR was 1.86 (1.20–2.86) when spatial accessibility to general food outlets was low. There was no significant relationship of overweight with either nature PA facilities or other food outlets (bakeries and fast-food outlets).Conclusion:These results indicate that disparities in spatial accessibility to PA facilities and to general food outlets may amplify the risk of overweight in socio-economically disadvantaged youth. These data should be relevant for influencing health policies and urban planning at both a national and local level.

Lower serum osteocalcin is associated with more severe metabolic syndrome in elderly men from the MINOS cohort

BACKGROUND Bone has emerged as an endocrine organ regulating energy metabolism through secretion of osteocalcin. In epidemiological studies, presence of metabolic syndrome (MetS) was associated with lower osteocalcin level. OBJECTIVES We evaluated whether osteocalcin level was associated with MetS severity in men and whether it was more strongly associated with MetS compared with N-terminal propeptide of type I procollagen (PINP), bone-specific alkaline phosphatase (BAP), and C-terminal telopeptide of type I collagen (βCTX). METHODS We included 798 men aged 51-85 years for total osteocalcin measurement. Number of MetS criteria was used to define severity. We used polytomous logistic regression to assess the relationship between MetS severity and osteocalcin level. RESULTS Thirty percent of men had MetS. In patients with MetS, the higher the number of MetS traits were present, the lower was the average osteocalcin level (0-2 criteria: 551 men: 19.5±6.7 ng/ml, three criteria: 155 men: 19.3±7.4 ng/ml, four criteria: 72 men: 17.3±5.7 ng/ml, and five criteria: 20 men: 15.0±5.1 ng/ml; P for trend=0.002).In the polytomous logistic regression model, an increase in osteocalcin level of 10 ng/ml was associated with lower prevalence of severe MetS: three criteria (odds ratio (OR)=0.93 (0.70-1.24)), four criteria (OR=0.54 (0.34-0.84)), and five criteria (OR=0.28 (0.10-0.82)) in comparison with no MetS (P for trend=0.008).After adjustment, using stepwise analysis of the polytomous logistic regression model, we observed that osteocalcin, age, and apparent free testosterone entered in the model but not other bone markers (PINP, βCTX, and BAP). CONCLUSION In older Caucasian men, total osteocalcin level was associated with MetS severity. Osteocalcin was more strongly associated with MetS severity than other bone turnover markers.

Leisure-time physical activity and sedentary behavior clusters and their associations with overweight in middle-aged French adults

Objective:To identify leisure-time physical activity (LTPA) and sedentary behavior patterns, as well as to investigate their relationships with overweight.Design:Cross-sectional study.Subjects:Men (n=2206) and women (n=2476) aged >45 years, living in France, enrolled in the SU.VI.MAX (Supplémentation en VItamines et Minéraux AntioXydants) study.Measurements:LTPA and sedentary behavior were assessed using the Modifiable Activity Questionnaire whereas weight and height were measured from study participants. Clusters were defined, by gender, with multiple correspondence analysis and cluster analysis successively, taking into account the type (walking, gardening, etc.) and duration of each physical activity performed, as well as the time spent watching television (TV) as typical sedentary behavior. Logistic regression models were used to assess associations with overweight.Results:Four physical activity and sedentary behavior clusters were identified among men and three among women. We chose as referent cluster the cluster associating ‘walking and gardening-low TV’ in men and the cluster associating ‘walking and gardening-high TV’ in women. Compared with the referent cluster and after adjustment for age, education level, smoking status and place of residence, the likelihood of overweight (defined as body mass index ⩾25 kg m−2) in women was lower for a ‘multiple activity-low TV’ cluster (odds ratio (OR)=0.66, 95% confidence interval=0.54–0.81) and for a cluster associating ‘endurance physical activity-low TV’ (OR=0.42 (0.29–0.60)). Compared with the referent cluster and after adjustment, the likelihood of overweight in men was decreased for the ‘endurance physical activity’ cluster (OR=0.66, (0.52–0.84)), whereas no significant association was found with the other clusters.Conclusions:Patterns combining specific types of physical activity and sedentary behavior were identified and differed in their relations to overweight in adults. The identification of global patterns of activity allows us to go beyond a simple decreased activity-increased body weight approach and adds to our understanding of the associations of specific forms and grouping of activity with overweight in adults.

Risk of relapse after natalizumab withdrawal Results from the French TYSEDMUS cohort

Objective: To assess disease activity within 12 months after natalizumab (NZ) discontinuation in a large French postmarketing cohort. Methods: In France, patients exposed at least once to NZ were included in the TYSEDMUS observational and multicenter cohort, part of the French NZ Risk Management Plan. Clinical disease activity during the year following NZ discontinuation was assessed in this cohort. Time to first relapse after NZ stop was analyzed using Kaplan-Meier method and potentially associated factors were studied using a multivariate Cox model. Results: Out of the 4,055 patients with multiple sclerosis (MS) included in TYSEDMUS, 1,253 discontinued NZ and 715 of them had relevant data for our study. The probability of relapse within the year after NZ stop was estimated at 45% (95% confidence interval 0.41–0.49). Conclusions: This large and systematic survey of patients with MS after NZ withdrawal allows quantifying the risk of increased disease activity following treatment discontinuation. This study provides large-scale, multicenter, systematic data after NZ cessation in real-life settings.