IACC/OARC ASD Research Publications AnalysisSkip Over Navigation Links Skip Over Navigation Links
- Executive Summary
- Chapter One: Trends in Autism Research Topics and Publications
- What research themes are prominent in autism publications?
- How were 2010 publications distributed across IACC Strategic Plan Critical Question areas?
- How much has autism research grown?
- Which Critical Question research areas are showing the strongest growth?
- Main findings from analysis of trends in autism research topics and publications
- Spotlight On Risk Factor Research
- Spotlight On Treatments And Interventions Research
- Chapter Two: Impact and Maturity Of The Autism Research Field
- Chapter Three: Global Autism Research Funders
- Chapter Four: Global Autism Publications and Collaborations
- Appendix I: Methodology for Identifying ASD-Related Research Publications and Supplemental Primary Research Publication Counts
- Appendix II: Automated Categorization of ASD Publications (1980-2009)
- Appendix III: Web of Science® Journal Subject Categories
- Appendix IV: Web of Science® Citation Data
- Appendix V: Full Funder List for 2010 ASD Publications
- Appendix VI: Country Co-Authorship Pairs in 2010 ASD Publications
- Appendix VII: 2010 ASD Publication Counts by Country
- Appendix VIII: Methodology for Calculating World Share of Autism Research Publications
- List of Figures
- Figure 1. The Seven IACC Strategic Plan Critical Questions and Corresponding Research Areas
- Figure 2. Autism Research Pipeline
- Figure 3. Research Methods Used in the ASD Research Publications Analysis
- Figure 4. Main Questions Addressed in the ASD Research Publications Analysis Report
- Figure 5. Autism Publications Word Cloud
- Figure 6. Distribution of 2010 Primary Research Publications within the Seven Critical Question Areas of the IACC Strategic Plan
- Figure 7. Growth in ASD-Related Publications, 1980 to 2010
- Figure 8. Growth in ASD Research Publications by Critical Question Area within the IACC Strategic Plan, 1981 to 2010
- Figure 9. Number and Fold Growth of ASD Publications from 2000 to 2010
- Figure 10. Publication Output and Trends in Subcategories of Autism Risk Factor Research
- Figure 11. Publication Output and Trends in Subcategories of Autism Treatments and Interventions Research
- Figure 12. Autism Research Citation Rate from 1980 to 2009
- Figure 13. Impact of Autism Publications Compared to Average Citation Rates in Related Publications, 1995 to 2009
- Figure 14. Proportion of Highly Cited Autism Publications from 1995 to 2009
- Figure 15. Types of US and non-US Funders Acknowledged in 2010 Autism Publications
- Figure 16. Overlap Between Different Types of Funders Acknowledged in 2010 Autism Publications
- Figure 17. Patterns of Strategic Research Emphasis by Type of Funder in 2010 Autism Publications
- Figure 18. Extent of Global Autism Research and International Collaborations in 2010
- Figure 19. Global Growth in Autism Publications by Country, 1980 to 2010
- Figure 20. Author Countries for ASD-Related Publications as a Share of the World Total, 1980 to 2010
- Figure 21. International Autism Publication Collaboration Networks in 1990, 1995, 2000, 2005, and 2010
- Figure 22. Extent of International Collaboration in Autism Research, 1980 to 2010
- Figure 23. Impact of Collaborative International Autism Publications, 1995 to 2009
- Figure 24. Impact of Collaborative Publications with Authors from Multiple Institutions, 2000 to 2010
- Figure 25. State by State Number of US Autism Publications in 2010
- Figure 26. Extent of Institutional and International Collaboration in US Autism Research, 1980 to 2010
- Figure A-27. Growth in ASD Primary Research Publications by Critical Question Area, 1981 to 2010
- Figure A-28. Number and Fold Growth of ASD Primary Research Publications from 2000 to 2010
- Figure A-29. Primary Research Publication Output and Trends in Subcategories of Autism Risk Factor Research
- Figure A-30. Primary Research Publication Output and Trends in Subcategories of Autism Treatments and Interventions Research
- List of Tables
- Table 1. 2010 Funders Acknowledged on 10 or More Publications
- Table 2. Top 25 Countries Publishing Autism Research in 2010
- Table 3. Top 25 Institutions Publishing Autism Research Globally in 2010
- Table A-4. Web of Science® and MEDLINE Article Types Classified as Secondary Articles
- Table A-5. Journals in which All Publications Were Classified as Secondary Research
- Table A-6. Comparison Group: Journal Subject Categories Comprising 75% of ASD Publications Since 1980
Spotlight on Risk Factor Research
Publication Output and Trends in Subcategories of Autism Risk Factor Research
Figure 10. Publication Output and Trends in Subcategories of Autism Risk Factor Research. The pie graph (top) illustrates relative proportions of research articles published in 2010 in three subcategories of ASD risk factor research and the line graph (bottom) shows the increase in number of publications in each subcategory over time from 1980 to 2010. Genetic Risk Factors research had the greatest number and proportion of publications, while the emerging field of Epigenetics had the smallest number and proportion of publications. The number of publications in each subcategory has been increasing over time, especially since 1999 for Genetic Risk Factors and Environmental Risk Factors and since 2006 for Epigenetics. Publications in this figure include both primary and secondary research. See Figure A-29 in Appendix I for publication output by primary research only.
With 1 in 88 children affected by autism, the patient and research communities feel a sense of urgency to identify risk factors that may be contributing to the rise in autism prevalence. Autism risk factor research has yielded some strong leads, but much work remains to identify a more complete picture of the risk factors that play the most significant role in the development of autism. Scientific evidence suggests that genetic and environmental risk factors form a complex web of interactions that determine whether a person develops an autism spectrum disorder.
To provide a clearer picture of research on autism risk factors, risk factor research publications were further classified into three subcategories:
- Genetic Risk Factors: This research includes efforts to identify new genes that are implicated in increased risk for ASD or to better understand previously identified genetic risk factors. Since the completion of the human genome map in 2003, scientists have identified a flood of genetic mutations that contribute to a variety of human diseases and disorders, and a few hundred genes have been implicated in autism.9,10,11 Some individuals on the autism spectrum have syndromes that result from single gene mutations, such as fragile X, tuberous sclerosis, and Rett syndrome; however, it is estimated that single gene disorders may only account for ~10-20% of all autism cases.12 The majority of the genetic mutations and alterations identified to date have much more subtle effects, individually accounting for only a small increase in risk.
- Environmental Risk Factors, including studies on the interaction of genes with the environment:iv Researchers are actively searching for pre- and postnatal environmental risk factors, either alone or in combination with genetic susceptibility (gene-environment).13 Some examples of environmental factors currently being explored in autism risk factor research include maternal dietary factors, maternal medications taken during pregnancy, child and maternal response to immune challenges and infection, environmental contaminants and toxins, as well as social changes in reproductive patterns and parental age. Environmental factors can interact with genetic factors in numerous ways. For example, they can cause novel mutations called de novo mutations in parents' germ line DNA. These molecular events can significantly affect development at various points throughout the lifespan.
- Epigenetic Processes: Epigenetics, an emerging area of research, is the study of heritable changes in gene function (such as methylation of DNA) that occur without changes to the DNA sequence. Environmental factors can alter epigenetic processes by affecting the molecules that bind DNA and control gene function. These epigenetic changes can be passed along from one generation to the next and have far-ranging biological consequences, potentially contributing to autism risk.14,15
In this analysis, which includes both primary and secondary research publications, Genetic Risk Factor publications comprised the largest share of 2010 publications (56%), followed by Environment (39%) and Epigenetics (5%). Major upturns in both Genetic and Environmental research have occurred in the last decade. An appreciable increase in genetics publications can be seen around 1998, and the field has matured since 2000, with large-scale genetics research now commonplace in the autism field. Environmental Risk Factor research is somewhat less established, but it has acquired substantial momentum over the last decade. Due to the relative youth of the Epigenetics research field in general, research on the role of epigenetics in autism has only emerged in the last few years, and represents a growing area of autism science. Very similar trends were observed when publication output analysis was restricted to primary research publications only. See Figure A-29 in Appendix I for more details. It will be important to continue to track developments in risk factors research to see if current trends continue or new research areas emerge.
All material appearing in this report is in the public domain and may be reproduced, copied, or used in presentations and publications. A suggested citation follows.
Office of Autism Research Coordination (OARC), National Institute of Mental Health and Thomson Reuters, Inc. on behalf of the Interagency Autism Coordinating Committee (IACC). IACC/OARC Autism Spectrum Disorder Research Publications Analysis Report: The Global Landscape of Autism Research. July 2012. Retrieved from the Department of Health and Human Services Interagency Autism Coordinating Committee website: http://iacc.hhs.gov/publications-analysis/july2012/index.shtml