Biomedical subjects

Mathieu Forster

Publications and source records attributed to Mathieu Forster.

3 recordsLinked to original sources

PubMed2006

Community unemployment and immigrants' health in Montreal.

This research examines the relationship between community unemployment and the physical and mental health of immigrants in comparison to non-immigrants in Montreal under the hypothesis that high unemployment in the community may generate more negative effects on the health of immigrants than on non-immigrants. Possible gender differences in these associations are also examined. Montreal residents were studied via multilevel analysis, using both individual survey data and neighbourhood data from 49 police districts. Individual-level data were excerpted from a 1998 health survey of Montreal residents, while neighbourhood data originated from survey data collected in the 49 Montreal police districts and the 1996 Canadian Census. The associations between community unemployment and self-rated health, psychological distress and obesity are examined, and hypotheses regarding the modifying mechanisms via which male and female immigrants may run a greater risk of poor health than non-immigrants when living in areas of high unemployment were tested. Between neighbourhoods, variations in the three health outcomes were slight, and differences in health were not associated with differences in community unemployment. The associations between community unemployment and health varied according to immigration status. At the individual level, immigrants do not differ from non-immigrants with respect to the three health indicators, except that second-generation males are slightly heavier. However, when living in areas of high unemployment, immigrants tend to report poor physical and mental health in comparison to non-immigrants. Among first-generation immigrants, community unemployment was associated with psychological distress. Among second-generation immigrants, the probability of obesity and poor self-rated health increased significantly for those living in areas with high unemployment, but these associations reached statistical significance only for men. Findings among first-generation immigrants are interpreted with respect to the effects of possible discrimination in areas with low job availability. Among second-generation men, poor physical health and obesity may be the result of poor health habits stemming from perceived lack of life opportunities.

Adolescent↗

PubMed2005

From walkability to active living potential: an "ecometric" validation study.

BACKGROUND: The purpose of this paper is to establish the reliability and validity of a neighborhood-level measure of active living potential by applying principles of ecometrics. METHODS: Following a 3-day training session, observers (n =8) were provided with a map of a predetermined walking route constructed through the joining of ten randomly selected street blocks. Then, using an 18-item observation grid, pairs of observers performed ratings of 112 neighborhoods. Resulting observations produced a hierarchically structured data set including 4032 observations nested within observers, which in turn were nested within neighborhoods. Data from the 2001 Canadian census were linked to the neighborhood data. RESULTS: Application of ecometric multilevel modeling analyses showed that once interitem and interobserver variability were statistically controlled, about one third of the variability in observations were at the between-neighborhood level. Reliability estimates were 0.78 for items measuring activity-friendliness, 0.76 for safety, and 0.83 for density of destinations. Assessment of the convergent validity of the instrument identified that safety of the environment was positively associated with neighborhood affluence. Density of destinations was negatively associated with affluence and positively associated with higher proportions of persons in the neighborhood walking to work. CONCLUSIONS: The three dimensions of the neighborhood active-living potential measure have good reliability and convergent validity and are able to capture between neighborhood differences. Measurement characteristics would have been difficult to ascertain without the ecometrics methodology.

Environment Design↗

PubMedDate not supplied

[Multilevel model applications to the analysis of longitudinal data].

This work is an introduction to repeated measurement analysis for longitudinal studies. It uses a two stage modelling framework, using hierarchical linear models with two levels. The first level pertains to the repeated measures, the second level pertains to the individual. For the last 25 years, hierarchical linear models have been used in the Social Sciences to analyse data coming from organizations with multiple levels. Their applications have been extended to the study of change in populations, both to describe the average change in an outcome variable in a population and to analyse the factors associated with variability in the individual trajectories of change. In this article, the basic concepts are introduced: between subjects and within subjects variability, the person-specific model for the individual trajectory and the between person model to describe how individuals vary in their trajectories, fixed and random effects, linear and quadratic growth models. At the end of each section, an illustration is given for the study of cognitive function of the older people cohort "Aging in Leganés", followed in four occasions between 1993 and 1999. Results from fitting the models to answer the most frequently asked research questions in the descriptions and analysis of individual change are presented. Lastly, we present possible generalizations of these linear models to non linear situations which arise when outcomes are dichotomous, nominal or ordinal.

Aging↗