ENVIRONMENTAL

EPIDEMIOLOGY OF

PSYCHOSES:

Lessons from Nottingham

Jouko MiettunenDepartment of Public Health and Primary CareInstitute of Public HealthUniversity of Cambridge June 17th, 2003

PSYCHOTIC DISORDERS

chronic, severe, and disabling brain diseases

life-time prevalence approximately 1% in schizophrenia 1% other psychoses

more common in urban than in rural areas

more common in western countries

POSSIBLE ENVIRONMENTAL RISK FACTORS

related to urban birth or to upbringingpopulation densitystressful life-events air pollution social deprivation temporal order can be the opposite

social drift? more healthy people may move out from deprived

areas?

Nottingham Health Authority Area

about 600,000 people in 105 electoral wards

districts of Nottingham, Ruschliffe, Broxtowe,

Gedling and Ashfieldseveral previous studies (1969-1988) on

schizophrenia and other psychoses possible to estimate trends in incidence

relatively high social deprivation and incidence of schizophrenia

SAMPLES OF THE STUDYSIN DATA

“Schizophrenia Incidence in Nottingham” all incidence cases of psychoses in Nottingham Health Authority Area

1.6.1992 - 31.5.1994 167 cases (166 with known address)

ÆSOP DATA “Aetiology and Ethnicity in Schizophrenia and Other Psychoses” three-centre study (other centres are Bristol and South London) all incidence cases of psychoses in Nottingham Health Authority Area

1.8.1997 - 31.7.1999 206 cases (202 with known address)

INDIVIDUAL VARIABLES DISTRIBUTIONS 1992-94 (N=167) 1997-99 (N=206)

Gender: males 98 (59%) 123 (60%)Median age 28 y 30 yDiagnoses

Narrow schizophrenia 56 67 Broad schizophrenia 82 116 Affective psychosis 85 90

Ethnic groups White 122 (73%) 159 (77%) African-Caribbean 26 (16%) 26 (13%) Other 19 (11%) 21 (10%)

POPULATION DATA

Census 1991 population of Nottingham

population at risk (16 to 64 years): 389,389

after under-enumeration corrections: 399,439

till 1992-94 population has increased approximately 2%

and till 1997-99 approximately 6% from this estimate

ELECTORAL WARD LEVEL VARIABLES

Multiple Deprivation Index 2000 Income

Employment

Housing

Health deprivation and disability

Education, skills and training

Geographical access to services

population density

proportion of ethnic minorities

HYPOTHESES OF THE STUDY

Incidence of psychoses is higher in more deprived areas (and/or

in areas with higher population density)

Incidence of psychoses among ethnic minorities is relatively

higher in areas with lower proportion of ethnic minorities lack of social support?

CASES 1992-94

02

15

0

21

0

22

1

11 3

01

0

4

1

04

2

2

3

01

10

0

0

2

01 0

1

12 01

00

1

017 4 3

113

0 04

1

044

68

0

98 51

2

056 6

35 0 0

0

2 2 50

0

00 2

01 11 0 00 0

000

00

00

0

0 1

1

0

Deprivation:High to low

11

34

2

01

1

11

0

10 4

11

0

3

0

64

0

2

3

00

01

0

0

1

10 0

1

42 00

20

0

038 5 4

320

0 07

0

045

89

0

52 55

2

044 4

80 1 1

0

4 6 02

0

13 3

03 35 4 22 0

331

01

00

0

0 1

1

1

CASES 1997-99

Deprivation:High to low

ANNUAL INCIDENCE OF ALL PSYCHOSES BY SOCIAL DEPRIVATIONNOTTINGHAM 1992-1994

3424

170

77

18 14

160

71

18 15

222

53

12 11

272

0

0

50

100

150

200

250

300

ALL white afro-c. others

I (high)

IV(low)

II

III

3929

204

64

19 16

128

53

22 20

167

70

20 18

136

69

0

50

100

150

200

250

ALL white afro-c. others

ANNUAL INCIDENCE OF ALL PSYCHOSES BY SOCIAL DEPRIVATIONNOTTINGHAM 1997-1999

I (high)

II

III

IV (low)

PLAN FOR ANALYSES

Age-standardised rates (Nottingham as a standard)

Two studies separately and pooled

Results by

Sex

Ethnic group

Subdiagnoses

narrow schz, broad schz and affective psychosis

each of the six variables in the deprivation score

Poisson regression analyses

LIMITATIONS

Electoral ward as a unit?

Case-ascertainment?

Census population?

Social deprivation scores? analyses can be repeated with other scores

Causality?

FUTURE WORK (1)

Smaller units than electoral wards enumeration districts (no information on ethnicity) using e.g. principal component analysis

Census 2001 variables are soon available update all the analyses with new population data update all the the analyses with new social deprivation variables combinations of census 1991 and 2001 variables

FUTURE WORK (2)

Case-control study of ÆSOP multilevel analyses with individual level variables

e.g. social class

ÆSOP is a three-centre study replicate the analyses in Bristol and South London

CONCLUSIONS

Preliminary findings: incidence of schizophrenia is about 1.5 more

common in the most deprived areas

CONCLUSIONS

Preliminary findings: incidence of schizophrenia is about 1.5 more

common in the most deprived areas

Much more work is needed in this thesis and also elsewhere to study social deprivation and incidence of psychoses

All your comments will be very helpful

Thank You!