Examining relationships between the Danish Composite Deprivation Index and risk of developing schizophrenia: A national multilevel analysis

ORCID

Abstract

BACKGROUND: Few population-based multilevel analyses examining individual- and neighborhood-level risk factors for schizophrenia have been conducted.

METHODS: A study cohort of all persons born in Denmark from 1990 to 1999 was followed for diagnosis with schizophrenia. Follow-up was initiated at 10th birthday and terminated at death, emigration, incident diagnosis, or 31st December 2018, whichever came first. A Danish Composite Deprivation Index was derived using 10-year weighted average neighborhood-level indicators in 1990-1999 categorized into five domains: Income; Employment; Education, Skills & Training; Health & Disability; and Crime. By fitting multilevel log-linear Poisson regression models, neighborhood-level deprivation indicators were examined with and without adjustment for individual-level covariates.

RESULTS: Four neighborhood-level deprivation domains, Employment, Education, Skills & Training, Health & Disability, and Crime, as well as the Danish Composite Deprivation Index (adjusted IRR 1.14; 95 % credibility interval 1.10-1.17), were associated with elevated risk independent of individual-level deprivation measures. The specific neighborhood-level indicators linked with the highest adjusted elevations in risk were: Proportion of inhabitants aged 18-22 years who did not complete primary school before age 18 (adjusted IRR 1.23; 1.20-1.27); Proportion of inhabitants convicted for any violent crime (adjusted IRR 1.19; 1.16-1.23); and Proportion of inhabitants convicted for any crime resulting in a custodial sentence (adjusted IRR 1.15; 1.12-1.18).

CONCLUSION: This novel population-based multilevel analysis has evidenced the independent associations of neighborhood-level deprivation indicators on schizophrenia risk elevation. Replication is needed in other populations to inform the refinement of preventive strategies.

Publication Date

2025-01-01

Publication Title

Schizophrenia Research

Volume

285

ISSN

0920-9964

Acceptance Date

2025-09-01

Deposit Date

2025-09-15

Embargo Period

2026-09-08

Funding

This study was supported by BERTHA - the Big Data Centre for Environment and Health funded by the Novo Nordisk Foundation Challenge Programme (grant NNF17OC0027864 ). R.T.W. is funded by the National Institute for Health and Care Research (NIHR) Manchester Biomedical Research Centre (grant number NIHR203308 ) and by the NIHR Greater Manchester Patient Safety Research Collaboration (grant number NIHR204295 ).

Keywords

Deprivation, Epidemiology, Multilevel analysis, Risk factors, Schizophrenia

First Page

52

Last Page

59

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This item is under embargo until 08 September 2026

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