Saturday, May 22, 2010
Franklin Hall B Level 4 (Philadelphia Marriott Downtown)
9:00 AM
M. Ikonen
,
Department of Child Psychiatry, University of Turku, 20014 Turku, Finland
P. N. Banerjee
,
Epidemiology, Columbia University/NYSPI, New York, NY
S. Hinkka-Yli-Salomäki
,
Department of Child Psychiatry, University of Turku, 20014 Turku, Finland
K. M. Lampi
,
Department of Child Psychiatry, University of Turku, 20014 Turku, Finland
H. Helenius
,
Department of Biostatistics, University of Turku, 20014 Turku, Finland
I. W. McKeague
,
Department of Biostatistics, Columbia University, New York, NY
A. S. Brown
,
Epidemiology, Columbia University/NYSPI, New York, NY
A. Sourander
,
Department of Child Psychiatry, University of Turku, 20014 Turku, Finland
Background:
Incidence and time trends of autism spectrum disorders (ASD) have been explored in several studies in different populations. Both public and scientific debate of the increased incidence of these conditions has recently achieved considerable interest. Some studies also indicate this might be part of a broader epidemiological phenomenon among child neuropsychiatric disorders.
Objectives: The purpose of the study is to explore how the number of new ASD cases diagnosed in Finland has changed in twenty years of time. We will examine cumulative incidence in a population-based cohort study and evaluate possible trends over time. We aim to analyze trends of incidence in different diagnostic subgroups based on International Statistical Classification of Diseases, 10th Revision (ICD-10), as well as to examine possible trends of gender distribution.
Methods: For the present study, we used the population-based birth cohort of the Finnish Prenatal Study of Autism and Autism Spectrum Disorders (FIPS-A), which is a large, register-based study of ASD in a national birth cohort. The study cohort includes all children born in Finland from 1987-2007. Data on ASD outcomes were obtained from the Finnish Hospital Discharge Register (FHDR). In this study, we included all registered diagnosed cases of childhood autism, Asperger´s syndrome and pervasive developmental disorder (PDD) or pervasive developmental disorder – not otherwise specified (PDD-NOS) using diagnostic criteria from ICD-10. Incidence rates for different subgroups of ASD were calculated for five 4-year time periods: 1988-1991, 1992-1995, 1996-1999, 2000-2003 and 2004-2007.
Results: Incidence was determined for ASD for the total 20-year study period and for five 4-year intervals. In the total study period, 4586 cases (3575 male, 1011 female) were diagnosed with childhood autism, Asperger´s syndrome or PDD/PDD-NOS. Incidence was age-adjusted to the determined population at risk (0-15 years of age). The incidence of ASD for the total study period was 23/100 000/year. Preliminary results indicate that for childhood autism, age-adjusted incidence seems to be significantly higher between years 1996-1999 compared to other intervals. For other diagnostic subgroups, incidence rates seem to be more stable over time.
Conclusions: Preliminary results suggest that there seem to be significant differences in the cumulative incidence rates across different time periods for ASD. Age- and gender-specific results of time trends will be examined further for diagnostic subgroups.
