title: Urban-rural differences in incidence rates of psychiatric disorders in Denmark.
abstract: People born in densely populated areas have a higher risk of developing schizophrenia, bipolar disorder and autism.
  
  
  
  The purpose of this study was to investigate whether urban-rural differences in place of birth influence a broad range of mental disorders.
  
  
  
  Population-based cohort study of everyone born in Denmark between 1955 and 2006 (n = 2 894 640). Main outcome measures were incidence rate ratios for five levels of urbanisation and summary estimates contrasting birth in the capital with birth in rural areas.
  
  
  
  For all psychiatric disorders, except intellectual disability (ICD-10 'mental retardation') and behavioural and emotional disorders with onset in childhood, people born in the capital had a higher incidence than people born in rural areas.
  
  
  
  Birth in an urban environment is associated with an increased risk for mental illness in general and for a broad range of specific psychiatric disorders. Given this new evidence that urban-rural differences in incidence are not confined to the well-studied psychotic disorders, further work is needed to identify the underlying aetiopathogenic mechanisms.
authors.affiliation: Evangelos Vassos, MD, PhD, Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, UK; Esben Agerbo, DrMedSc, National Centre for Register-Based Research, Aarhus University, Business and Social Sciences, Aarhus, Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus and The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark; Ole Mors, MD, PhD, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, and Research Department P, Aarhus University Hospital, Risskov, Denmark; Carsten Bøcker Pedersen, DrMedSc, National Centre for Register-Based Research, Aarhus University, Business and Social Sciences, Aarhus, Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus and The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark evangelos.vassos@kcl.ac.uk.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Vassos
authors.affiliation: Evangelos Vassos, MD, PhD, Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, UK; Esben Agerbo, DrMedSc, National Centre for Register-Based Research, Aarhus University, Business and Social Sciences, Aarhus, Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus and The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark; Ole Mors, MD, PhD, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, and Research Department P, Aarhus University Hospital, Risskov, Denmark; Carsten Bøcker Pedersen, DrMedSc, National Centre for Register-Based Research, Aarhus University, Business and Social Sciences, Aarhus, Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus and The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark.
authors.forename: Esben
authors.initials: E
authors.lastname: Agerbo
authors.affiliation: Evangelos Vassos, MD, PhD, Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, UK; Esben Agerbo, DrMedSc, National Centre for Register-Based Research, Aarhus University, Business and Social Sciences, Aarhus, Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus and The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark; Ole Mors, MD, PhD, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, and Research Department P, Aarhus University Hospital, Risskov, Denmark; Carsten Bøcker Pedersen, DrMedSc, National Centre for Register-Based Research, Aarhus University, Business and Social Sciences, Aarhus, Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus and The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark.
authors.forename: Ole
authors.initials: O
authors.lastname: Mors
authors.affiliation: Evangelos Vassos, MD, PhD, Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, UK; Esben Agerbo, DrMedSc, National Centre for Register-Based Research, Aarhus University, Business and Social Sciences, Aarhus, Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus and The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark; Ole Mors, MD, PhD, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, and Research Department P, Aarhus University Hospital, Risskov, Denmark; Carsten Bøcker Pedersen, DrMedSc, National Centre for Register-Based Research, Aarhus University, Business and Social Sciences, Aarhus, Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus and The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark.
authors.forename: Carsten Bøcker
authors.initials: CB
authors.lastname: Pedersen
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology*; D008875:Middle Aged; D012042:Registries / Q000706:statistics & numerical data*; D012424:Rural Population / Q000706:statistics & numerical data*; D014505:Urban Population / Q000706:statistics & numerical data*; D055815:Young Adult