Læknablaðið : fylgirit - 01.08.2003, Page 79

POSTERS / 27TH NORDIC PSYCHIATRIC CONGRESS I
P - 73 Friday 15/8,14:00-15:00
The effects of influenza on risk of developing
schizophrenia
Haukur Freyr Gylfason MA, Faculty of Social Scicnce, University of Iceland, 101
Reykjavík, Iceland. Stefánsson B, Smári J, Tómasson H.
haukurgy@hi.is
Background: The first opportunity to study the effects of influenza
on schizophrenia was after the influenza epidemic in 1918. That is
because it was not until the late 18th century that Kraepelin de-
scribed the symptoms of schizophrenia. In 1926 Menninger dis-
covered that schizophrenia was the most frequent mental illness
that followed the influenza epidemic eight years earlier, and by
doing so started a debate that is yet to be decided.
Method: Data from the Icelandic State Social Security Institute was
used to test the hypothesis that exposure to influenza during the
second trimester of pregnancy would increase the risk for adult
schizophrenia. Participants in this study were almost the total popu-
lation of Iceland, and all those who had been diagnosed with schizo-
phrenia and received disabilities for the last half a century. Analysis
of transition data was used to record the sequence of states that were
occupied and the times at which movements between them occurred
(not diagnosed with schizophrenia - diagnosed with schizophrenia).
Results: The main results were that if there was an increased likeli-
hood for maternal influenza infection in the second trimester then
the child was at more risk of being diagnosed with schizophrenia
later in life.
Condusion: The research supports the hypothesis that maternal
influenza during pregnancy is a risk factor for schizophrenia.
P - 74 Friday 15/8,14:00-15:00
Parental age and risk for schizophrenia: A nested case-
control study
Mujella Byrne1, MSc, PhD, Esben Agerbo1, MSc, Henrik EwalcR, DMSc, William
W. Eaton-\ PhD, Preben Bo Mortensen1, MD, DMSc.
•National Centre for Register-Based Research, Aarhus University, Taasingegade 1,
DK-8000 Aarhus C, Denmark, ^lnstitute for Basic Psychiatric Research, Psychiatric
Hospital in Aarhus, Skovagervej 2, DK-8240 Risskov, Denmark, -^Department of
Mental Hygiene, School of Hygiene and Public Health, Johns Hopkins University,
615 N. Wolfe Street, Baltimore, MD 21205, USA.
We investigated the reported association between advanced pater-
nal age and risk for schizophrenia. Unlike previous studies we in-
vestigated whether this association could be explained by social
factors or family history of psychiatric illness.
A national population-based nested case-control study based on
Danish longitudinal register data was conducted. The sample inclu-
ded 7704 first admissions to or contacts with Danish psychiatric ser-
vices between 1981 and 1998 with an ICD-8 (until end of December
1993) or ICD-10 (from January 1994) diagnosis of schizophrenia,
and 192590 individually time-, age-, and sex- matched population
controls, their parents and siblings.
Paternal age was categorised into the following age groups: <20
years, 20-24 years, 25-29 years, 30-34 years, 35-39 years, 40-44 years,
45-49 years, 50-54 years, and >= 55 years. Maternal age was defined
as: <20 years, 20-24 years, 25-29 years, 30-34 years, 35-39 years, 40-
44 years, and >= 45 years. The risk for schizophrenia associated with
parental age was investigated by conditional logistic regression.
Adjusting for socioeconomic and demographic factors and
family psychiatric history, increased risk for schizophrenia was
identified in those with paternal age >= 55 (Incidence Rate Ratio
(IRR) 2.27; 95% CI 1.57-3.29). Significant sex interactions were ob-
served. Sex specific analyses suggested that females were at higher
risk from raised paternal age than males who were also at risk.
Increased risk for schizophrenia was associated with advanced
paternal age. The interactions between sex and age of the parent of
origin suggests that de novo genetic mutations occurring on the X
chromosome might be involved in the aetiology of schizophrenia in
males and females of older parents.
The study was funded by the Theodore and Vada Stanley Foun-
dation and by NIMH Grant #MH53188. NCRR is funded by the
Danish National Research Foundation.
P - 75 Friday 15/8,14:00-15:00
Mortality in schizophrenia over the last 60 years in the
township of Malmö
Lise-Lotte Nilsson. PhD, BSc in Social Work, Department of Psychiatry, University
Hospital of Malmö, Lund University, Sege Park 8 A, 205 02 Malmö, Svveden. Bcngt
Lögdberg.
lise-lotte.nilsson@swipnet.se
The mortality and the standardized mortality ratio (SMR) for
patients with the diagnosis of schizophrenia, and between 25-64
years of age, in the township of Malmö (population about 250 000)
in Southern Sweden were studied from about 1935 until 2003, by
analyses of patients’ records. Data will be presented from the time
period 1940-2000.
From about 1940-1960 most of the patients diagnosed with
schizophrenia were living at mental hospital, and the mortality was
similar to the general population, i.e. the standardized mortality
ratio was about 1. Over the ensuing decades, the standardized mor-
tality ratio increased about from 2 to 3 between 1960-1980, remained
unchanged around 2 between 1980-1990, but then increased again
from about 3 to 5 between 1990-2000, concomitant with the full
sectorization and the final closure of the mental hospital.
Analyses of relationships between trends in standardized morta-
lity ratio and organizational changes in psychiatry as well as societal
changes will be presented and discussed.
P - 76 Friday 15/8,14:00-15:00
Schizoaffective disorders in Denmark 1970-2000
Thomas Munk Laursen, Researcher, MSc, National Centre for Register-based
Research, Taasingegade I, 8000 Aarhus C, Denmark. Rodrigo Labouriau, Aksel
Bertelsen, Rasmus Licht, Preben Bo Mortensen.
tml@ncrr.dk
Background: Schizoaffective disorder is related to both schizophre-
nia and to affective disorders. To our knowledge, however, no
population-based study has investigated the association between
the risk of schizoaffective disorders and familial aggregation of
schizophrenia and affective disorders.
Læknablaðið / FYLGIRIT 48 2003/89 79