Understanding the effect of ethnic density on mental health: multi-level investigation of survey data from England
BMJ 2010; 341 doi: https://doi.org/10.1136/bmj.c5367 (Published 21 October 2010) Cite this as: BMJ 2010;341:c5367
- Jayati Das-Munshi, MRC training fellow in health services and health of public research1,
- Laia Becares, research fellow2,
- Michael E Dewey, professor of statistical epidemiology1,
- Stephen A Stansfeld, professor of psychiatry3,
- Martin J Prince, professor of psychiatric epidemiology1
- 1Institute of Psychiatry, King’s College London, London SE5 8AF, UK
- 2Department of Epidemiology and Public Health, University College London, UK
- 3Centre for Psychiatry, Queen Mary, University of London, Barts and the London School of Medicine, UK
- Correspondence to: J Das-Munshi jayati.das-munshi{at}kcl.ac.uk
- Accepted 3 August 2010
Abstract
Objectives To determine if living in areas where higher proportions of people of the same ethnicity reside is protective for common mental disorders, and associated with a reduced exposure to discrimination and improved social support. Finally, to determine if any protective ethnic density effects are mediated by reduced exposure to racism and improved social support.
Design Multi-level logistic regression analysis of national survey data, with area-level, own-group ethnic density modelled as the main exposure.
Participants and setting 4281 participants of Irish, black Caribbean, Indian, Pakistani, Bangladeshi, and white British ethnicity, aged 16–74 years, randomly sampled from 892 “middle layer super output areas” in England.
Main outcome measures Common mental disorders (assessed via structured interviews); discrimination (assessed via structured questionnaire); and social support and social networks (assessed via structured questionnaire).
Results Although the most ethnically dense areas were also the poorest, for each 10 percentage point increase in own-group ethnic density, there was evidence of a decreased risk of common mental disorders, for the full ethnic minority sample (odds ratio 0.94 (95% confidence interval 0.89 to 0.99); P=0.02, trend), for the Irish group (odds ratio 0.21 (0.06 to 0.74); P=0.01, trend), and for the Bangladeshi group (odds ratio 0.75 (0.62 to 0.91); P=0.005, trend), after adjusting for a priori confounders. For some groups, living in areas of higher own-group density was associated with a reduction in the reporting of discrimination and with improved social support and improved social networks. However, none of these factors mediated ethnic density effects.
Conclusions A protective effect of living in areas of higher own-group ethnic density was present for common mental disorders for some minority groups. People living in areas of higher own-group density may report improved social support and less discrimination, but these associations did not fully account for density effects.
Footnotes
We thank Sally McManus, Emily Diment, and Claire Deverill (National Centre for Social Research) for assisting with retrieval and matching of area-level measures to the dataset; and Professor James Nazroo (University of Manchester) and Dr Mai Stafford (University College London) for advice in the planning and early stages of analysis of the study. JD thanks Professor Ian Roberts (London School of Hygiene and Tropical Medicine) for lively discussion around the social determinants of health and for helpful comments on earlier analyses.
Contributor: JD and MJP had the original idea for the study and developed the study design with LB and SAS. MED advised on statistical aspects of the study design in planning, analysis stages, and in responding to queries raised by peer reviewers. All authors were involved in discussion and interpretation of results. JD conducted all analyses and wrote the first draft. All authors contributed to the writing of further drafts. JD is guarantor for the study.
Funding: The Institute of Social Psychiatry provided a small funds grant to enable retrieval of area-level data, which was then matched to individual records by the National Centre for Social Research. JD is supported by an MRC fellowship. LB was partially supported by the Economic and Social Research Council (ESRC). None of the funding bodies played a part in the research protocol, data analyses, data interpretation, or writing of the report.
Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work other than the funding grant; no financial relationships with any organisations that might have an interest in the submitted work in the previous 3 years; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: Ethical approval was obtained from relevant approval bodies in the UK at the time of data collection. Access to the dataset for the purposes of secondary analysis was subject to the terms of an end user license agreement, and further ethical approval was not needed. Area-level data provided by the National Centre for Social Research was subject to approval by its data release committee.
Data sharing: The technical appendix and statistical code are available from JD at jayati.das-munshi@kcl.ac.uk. The data are available from the Economic and Social Data Service (http://www.esds.ac.uk) subject to an end-user license agreement.
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