To date, relatively few scientists are studying autism in China. Clearly the need there is great, for with its population of over a billion, we may be looking at millions of persons affected by autism. With this in mind, Autism Speaks partnered with China’s Fudan University to convene a meeting of leading international experts in autism and children’s health in Shanghai last week.
As part of this visit, I and development psychologist Alice Kau, Ph.D., of the National Institute for Child Health & Human Development, visited Xin Hua Hospital and its recently completed Shanghai Key Lab of Children’s Environmental Health. Both are affiliated Shanghai’s Jiao Tong University School of Medicine.
There we met the lab’s executive director, Jun Jim Zhang, MD, Ph.D., and his colleagues. In recent years, they have been studying how exposure to heavy metals such as mercury and lead affects child development. Environmental lead contamination, a problem largely minimized in the United States, remains a widespread problem in China, owing to unsafe disposal of lead products including waste from lead battery plants.
The Shanghai Key Lab’s affiliation with Xin Hua Hospital allows its scientists to collect blood samples at birth and throughout a child’s development. Their lab is also collecting information on intellectual function and other developmental behaviors. Among their projects is the Shanghai Birth Cohort, which will recruit 100,000 pregnant women from hospitals throughout Shanghai and follow their children throughout adolescence.
To date, the researchers at Shanghai’s Key Lab have been focusing their research on potential environmental causes of childhood asthma, sleep disorders and leukemia. Looking forward, they are keenly interested in expanding their research to include neurodevelopmental issues such as autism.
Thanks to our new collaboration, they will be participating in Autism Speaks Environmental Epidemiology of Autism Research Network. In doing so, they will be sharing their information with autism researchers in North America and elsewhere, even as they receive guidance on screening for autism spectrum disorder (ASD).
Given the unique physical, chemical and psychosocial environment in China, we believe that this collaboration can greatly advance our understanding of the environmental and genetic risk factors that contribute to the development of ASD. We look forward to working with this wonderful research team to help solve the autism puzzle in China, North America, and around the world.
by Alycia Halladay, Ph.D, Director of Environmental Science
Research using identical and fraternal twins is typically used to identify genetic influences on the development of ASD. This year, researchers studied a large group of twins and examined the concordance of different types of symptoms (1). Using this approach, the researchers found that the concordance of severe autism between identical twins and fraternal twins was about the same, indicating a strong environmental component to ASD severity. But what are those environmental factors? Epidemiological studies are providing clues.
At this year’s IMFAR, new data was presented that focused on studying groups of people and their exposures to a number of environmental factors. Each used different designs with their own unique advantages. For example, at UC Davis, the CHARGE study (www.beincharge.ucdavis.edu) examined the risk of developing autism following exposure to a number of factors that were identified through self report or medical records. Those that showed an association were antidepressant SSRI use (2) and metabolic disorders including hypertension and diabetes (3). On the other hand, a previously identified factor, maternal infection, was not associated (4). Why not? The researchers suggested that fever, not infection per se, may be a factor. Using self-report and medical records obtained prior to study entry may not accurately capture all relevant information, and an infection or fever may be missed in some reports. However, other types of information, such as method of birth, is easier to gather accurately. An analysis revealed that non-emergency or elective c-section deliveries did not show a significant association with autism, addressing a concern that many public and community stakeholders have expressed (5).
As an alternative to retrospective reports, the Early Markers of Autism Study in California is obtaining samples of blood from pregnant women by obtaining extra blood taken during the alpha-fetal protein screen that is banked. Not all states bank these samples for research, so this is a unique resource. By examining the levels of mercury in blood taken during pregnancy together with newborn blood spots, the researchers can get a more comprehensive picture of the prenatal environment. They reported no difference in mercury levels compared to those of non-affected children during gestation, and also reported no difference in thyroid hormone levels (6,7). Examination of subgroups of autism with regression did not change the results. While these data are incredibly novel and valuable, these studies were not designed to capture information throughout the entire pregnancy nor capture factors after birth
Another way to study exposures during pregnancy is through birth certificate data. In some states, the birth certificate contains information such as the place of birth and the occupation of the mother and the father. Using this information, scientists found that occupational exposures in mothers to certain chemicals resulted in an increased risk of ASD in offspring (8).
While each approach brings unique strengths, all researchers agree that the most comprehensive way to capture all information accurately, is a prospective design. This means identifying children as soon as possible and following them from that point on to gather every piece of relevant information from medical reports to blood samples. Autism Speaks is proud to co-sponsor such a study: the Early Autism Risk Longitudinal Investigation (EARLI). This groundbreaking project will provide even more answers to what causes autism, and needs the help of the community to do so.
So how can researchers blend or expand their research if they are using only one type of design? Autism Speaks and the National Institutes for Environmental Health Sciences are sponsoring a network of projects called the Environmental Epidemiology of Autism Research Network (EEARN). The goal of this network is to improve communication among researchers in this field, identify opportunities for collaborative projects and improve research tools for both existing, and new projects. Over 20 studies from 8 countries are represented in the network. We will keep you updated on the activity of the network, and we hope you will keep checking in for updates.
1. Understanding Clinical Variability In Autism: Results From a California Twin Study. W. Froehlich*1, S.
Cleveland1, A. Torres1, J. M. Phillips1, B. Cohen2, A. Fedele3, T. Torigoe2, J. Collins4, K. S. Smith5, L. Lotspeich1, L. A. Croen4, S. Ozonoff6, C. Lajonchere7, J. K. Grether5, N. Risch8 and J. Hallmayer1, (1)Stanford University, Stanford, CA, (2)Autism Genetic ResourceExchange, Los Angeles, CA, (3)Autism Speaks, Westmont, NJ,
United States, (4)Kaiser Permanente, Division of Research, Oakland, CA, (5)California Department of Public Health, Richmond , CA, (6)UC Davis MIND Institute, Sacramento, CA, (7)Autism Speaks, Los Angeles, CA, United States, (8)University of California San Francisco, San Francisco, CA
2. SSRI Use During Pregnancy and Risk of ASD or Developmental Delay In Children. R. A. Harrington*1,L. C. Lee1, C. K. Walker2, R. L. Hansen3, S. Ozonoff3 and I. Hertz-Picciotto4, (1)Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, (2)Department of Public Health Sciences, University of California at Davis, Davis, CA, (3)MIND Institute, University of California at Davis, Sacramento, CA, (4)Department of Public Health Sciences, University of California Davis, Davis, CA
3. The Role of Maternal Diabetes and Related Conditions In Autism and Other Developmental Delays. P. Krakowiak*1,2, A. A. Bremer3, A. S. Baker1, C. K. Walker1,4, R. L. Hansen2,3 and I. Hertz-Picciotto1,2, (1)Public Health Sciences, University of California, Davis, Davis, CA, (2)M.I.N.D. Institute, Sacramento, CA, (3)Pediatrics, University of California, Davis, Sacramento, CA, (4)Obstetrics & Gynecology, University of California, Davis, Sacramento, CA
4. Prenatal Influenza or Fever and Risk of Autism/Autism Spectrum Disorders. O. Zerbo*1, I. Hertz- Picciotto2,3, A. M. Iosif4, R. L. Hansen5,6,7 and C. K. Walker8, (1)Sacramento, CA, (2)University of California, Davis, Davis, CA, (3)Department of Public Health Sciences, University of California Davis, Davis, CA, (4)UC Davis, Davis, CA, (5)University of California, Davis, MIND Institute, Sacramento, CA, (6)MIND Institute, University of California at Davis, Sacramento, CA, (7)MIND Institute and Dept. of Pediatrics, University of California Davis, Davis, CA, (8)Department of Public Health Sciences, University of California at Davis, Davis, CA
5. Cesarean Birth and Autism Spectrum Disorder. C. K. Walker*1, P. Krakiowiak2, A. S. Baker3, R. L. Hansen4, S. Ozonoff5 and I. Hertz-Picciotto6, (1)Obstetrics & Gynecology, UC Davis, Sacramento, CA, (2)Public Health Sciences, UC Davis, Sacramento, CA, (3)Public Health Sciences, UC Davis, Davis, CA, (4)Pediatrics, M.I.N.D. Institute, UC Davis, Sacramento, CA, (5)Psychiatry and Behavioral Sciences, M.I.N.D. Institute, UC Davis, Sacramento, CA, (6)Public Health Sciences, M.I.N.D. Institute, UC Davis, Davis, CA
6. Prenatal and Neonatal Peripheral Blood Mercury Levels and Autism Spectrum Disorders. L. A. Croen*1, M. A. Lutsky1, C. Yoshida1, C. P. Alaimo2, M. Kharrazi3, J. K. Grether4 and P. Green2, (1)Kaiser Permanente Division of Research, Oakland, CA, (2)Civil and Environmental Engineering, Univ. of California Davis, Davis, CA, (3)Genetic Disease Screening Program, California Department of Public Health, Richmond, CA, (4)California Department of Public Health, Richmond, CA
7. Prenatal and Neonatal Thyroid Stimulating Hormone Levels and Autism Spectrum Disorder. M. A. Lutsky*1, C. Yoshida1, B. Lasley2, M. Kharrazi3, J. K. Grether4, G. Windham4 and L. A. Croen1, (1)Kaiser Permanente Division of Research, Oakland, CA, (2)Department of Population Health and Reproduction, UC Davis, Davis, CA, (3)Genetic Disease Screening Program, California Department of Public Health, Richmond, CA, (4)California Department of Public Health, Richmond, CA
8. Autism Spectrum Disorders In Relation to Parental Occupational Exposures During Pregnancy. G. Windham*1, J. K. Grether2, A. Sumner3, S. Li4, E. Katz5 and L. A. Croen6, (1)California Department of Public Health, Richmond, CA, (2)California Department of Public Health, Richmond, CA, (3)Vermont Department of Health, Burlington, VT, (4)Kaiser Permanente Divison of Research, Oakland, CA, (5)Occupational Health Branch, CA Department of Public Health, Richmond, CA, (6)Kaiser Permanente Division of Research, Oakland, CA