| 1. |
- Chaix, B, et al.
(författare)
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Comparison of a spatial approach with the multilevel approach for investigating place effects on health: the example of healthcare utilisation in France
- 2005
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Ingår i: Journal of Epidemiology and Community Health. - : BMJ. - 1470-2738 .- 0143-005X. ; 59:6, s. 517-526
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Tidskriftsartikel (refereegranskat)abstract
- Study objective: Most studies of place effects on health have followed the multilevel analytical approach that investigates geographical variations of health phenomena by fragmenting space into arbitrary areas. This study examined whether analysing geographical variations across continuous space with spatial modelling techniques and contextual indicators that capture space as a continuous dimension surrounding individual residences provided more relevant information on the spatial distribution of outcomes. Healthcare utilisation in France was taken as an illustrative example in comparing the spatial approach with the multilevel approach. Design: Multilevel and spatial analyses of cross sectional data. Participants: 10 955 beneficiaries of the three principal national health insurance funds, surveyed in 1998 and 2000 on continental France. Main results: Multilevel models showed significant geographical variations in healthcare utilisation. However, the Moran's I statistic showed spatial autocorrelation unaccounted for by multilevel models. Modelling the correlation between people as a decreasing function of the spatial distance between them, spatial mixed models gave information not only on the magnitude, but also on the scale of spatial variations, and provided more accurate standard errors for risk factors effects. The socioeconomic level of the residential context and the supply of physicians were independently associated with healthcare utilisation. Place indicators better explained spatial variations in healthcare utilisation when measured across continuous space, rather than within administrative areas. Conclusions: The kind of conceptualisation of space during analysis influences the understanding of place effects on health. In many contextual studies, viewing space as a continuum may yield more relevant information on the spatial distribution of outcomes.
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| 3. |
- Håkansson, Anders, et al.
(författare)
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Research methods courses as a mean of developing academic general practice
- 2005
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Ingår i: Scandinavian Journal of Primary Health Care. - 0281-3432. ; , s. 132-136
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Tidskriftsartikel (refereegranskat)abstract
- Since 1989, the authors have given courses in research methodology, and these courses are now given at six venues in southern Sweden, as well as in Denmark. The course corresponds to half a year's full-time study, with half the time devoted to lectures and studies of literature, while the rest is spent on an individual project under supervision. To enable part-time study, the course extends over 1(1/2) years. In 15 years roughly 1000 people, mainly physicians, have been given training in basic research methods. The course model has been appreciated by clinically active colleagues, who have been able to attend a course and simultaneously work with patients. Among the GPs in the region, one in five has taken this course, and one in five has then gone on to start formal PhD studies. The authors have thus succeeded in their goal of giving basic scientific schooling to many physicians and recruiting some for further research.
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| 4. |
- Johnell, K, et al.
(författare)
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Low adherence with antihypertensives in actual practice: the association with social participation - a multilevel analysis
- 2005
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Ingår i: BMC Public Health. - : Springer Science and Business Media LLC. - 1471-2458. ; 5:17
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Tidskriftsartikel (refereegranskat)abstract
- Background: Low adherence is a key factor in explaining impaired effectiveness and efficiency in the pharmacological treatment of hypertension. However, little is known about which factors determine low adherence in actual practice. The purpose of this study is to examine whether low social participation is associated with low adherence with antihypertensive medication, and if this association is modified by the municipality of residence. Methods: 1288 users of antihypertensive medication were identified from The Health Survey in Scania 2000, Sweden. The outcome was low adherence with antihypertensives during the last two weeks. Multilevel logistic regression with participants at the first level and municipalities at the second level was used for analyses of the data. Results: Low social participation was associated with low adherence with antihypertensives during the last two weeks (OR = 2.05, 95% CI: 1.05-3.99), independently of low educational level. However, after additional adjustment for poor self-rated health and poor psychological health, the association between low social participation and low adherence with antihypertensives during the last two weeks remained but was not conclusive (OR = 1.80, 95% CI: 0.90-3.61). Furthermore, the association between low social participation and low adherence with antihypertensives during the last two weeks varied among municipalities in Scania (i.e., cross-level interaction). Conclusion: Low social participation seems to be associated with low adherence with antihypertensives during the last two weeks, and this association may be modified by the municipality of residence. Future studies aimed at investigating health-related behaviours in general and low adherence with medication in particular might benefit if they consider area of residence.
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| 5. |
- Larsen, K, et al.
(författare)
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Appropriate assessment of neighborhood effects on individual health: Integrating random and fixed effects in multilevel logistic regression
- 2005
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Ingår i: American Journal of Epidemiology. - : Oxford University Press (OUP). - 0002-9262. ; 161:1, s. 81-88
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Tidskriftsartikel (refereegranskat)abstract
- The logistic regression model is frequently used in epidemiologic studies, yielding odds ratio or relative risk interpretations. Inspired by the theory of linear normal models, the logistic regression model has been extended to allow for correlated responses by introducing random effects. However, the model does not inherit the interpretational features of the normal model. In this paper, the authors argue that the existing measures are unsatisfactory (and some of them are even improper) when quantifying results from multilevel logistic regression analyses. The authors suggest a measure of heterogeneity, the median odds ratio, that quantifies cluster heterogeneity and facilitates a direct comparison between covariate effects and the magnitude of heterogeneity in terms of well-known odds ratios. Quantifying cluster-level covariates in a meaningful way is a challenge in multilevel logistic regression. For this purpose, the authors propose an odds ratio measure, the interval odds ratio, that takes these difficulties into account. The authors demonstrate the two measures by investigating heterogeneity between neighborhoods and effects of neighborhood-level covariates in two examples-public physician visits and ischemic heart disease hospitalizations-using 1999 data on 11,312 men aged 45-85 years in Malmo, Sweden.
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| 10. |
- Merlo, Juan, et al.
(författare)
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A brief conceptual tutorial of multilevel analysis in social epidemiology: linking the statistical concept of clustering to the idea of contextual phenomenon.
- 2005
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Ingår i: Journal of Epidemiology and Community Health. - : BMJ. - 1470-2738 .- 0143-005X. ; 59:6, s. 443-449
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Tidskriftsartikel (refereegranskat)abstract
- Study objective: This didactical essay is directed to readers disposed to approach multilevel regression analysis (MLRA) in a more conceptual than mathematical way. However, it specifically develops an epidemiological vision on multilevel analysis with particular emphasis on measures of health variation (for example, intraclass correlation). Such measures have been underused in the literature as compared with more traditional measures of association (for example, regression coefficients) in the investigation of contextual determinants of health. A link is provided, which will be comprehensible to epidemiologists, between MLRA and social epidemiological concepts, particularly between the statistical idea of clustering and the concept of contextual phenomenon. Design and participants: The study uses an example based on hypothetical data on systolic blood pressure (SBP) from 25 000 people living in 39 neighbourhoods. As the focus is on the empty MLRA model, the study does not use any independent variable but focuses mainly on SBP variance between people and between neighbourhoods. Results: The intraclass correlation (ICC = 0.08) informed of an appreciable clustering of individual SBP within the neighbourhoods, showing that 8% of the total individual differences in SBP occurred at the neighbourhood level and might be attributable to contextual neighbourhood factors or to the different composition of neighbourhoods. Conclusions: The statistical idea of clustering emerges as appropriate for quantifying "contextual phenomena" that is of central relevance in social epidemiology. Both concepts convey that people from the same neighbourhood are more similar to each other than to people from different neighbourhoods with respect to the health outcome variable.
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