Autism 2002 Mercury, Heavy Metals... Toxicity

Walter O. Spitzer, M.D., M.P.H., F.R.C.P.C. Emeritus Professor of Epidemiology at McGill University, Montreal, Dr. Spitzer is a member of the Institute of Medicine of the National Academy of Sciences of the USA. and Senior Scientist of the Foundation for Biomedical Sciences Integrity (Canada - USA - UK).

WHAT WE DO NOT KNOW ABOUT THE CAUSE OF AUTISM AND WHY

Issues related to the natural history of autistic syndromes will be reviewed in clinical and epidemiological terms. A justification of the current epidemic of autism will be given. Beyond that, a review of epidemiological research published to date will demonstrate that relationships between any potential causal factor and autism have not been ruled out nor have they been ruled in. Notably, there has not been any epidemiological research with undertaken with controls. Rigorous safety studies have not been done. Several studies alleging exoneration of one particular potential causal factor, measles-mumps-rubella triple vaccine (MMR), will be demonstrated to be inappropriate in methodology and largely irrelevant. Small sample sizes, inappropriately short follow up and the misuse of correlations to test hypotheses are among the shortfalls in methodology to be reviewed.

It is recognized that the efficacy (as opposed to the safety) of MMR has been adequately demonstrated. On the other hand, work to date in the clinic and the laboratory is not complete yet but increasingly suggestive of a key role of MMR as a determinant of at least some forms of autism.

A scientifically admissible research strategy will be formulated which could clarify what we do not know about prevention, treatment, and palliation, especially prevention. The centre-piece is a pivotal case control study to be expanded upon by Heinemann, L.A.J. in Part II of this exposition. Other tiles in the mosaic include completion of clinical and laboratory studies and improvement of descriptive epidemiology with emphasis on incidence studies in various regions. Linking all future work with genetics is crucially important. We are likely faced with a multifactorial web of causation and a spectrum of autistic conditions where the interactions must be understood.

Scientists in the clinic, the laboratory and the population along with the parents, the care givers and the government must assume a more interdependent and mutually supportive role. The problems must be solved with solid data, sound analysis and clinical judgment. Speculation and wishful thinking have no place in the elucidation of the causes and treatment of autism.

Dr. Lothar A.J. Heinemann, M.D., D.Sc. Dr. Heinemann's clinical professional background is in internal medicine and cardiology. He holds a Masters degree in clinical psychology. He defended two doctoral theses in science in 1967 and 1977, and was appointed Professor of Preventive Medicine in the Academy of Sciences in Berlin (Germany) in 1982. He was involved in clinical epidemiological research mainly focussed on cardiovascular and cancer epidemiology during the greater part of his career and in the last decade in pharmacoepidemiology. Currently he is Director of the Center for Epidemiology & Health Research, Berlin.

The first controlled epidemiological study of autism: an international approach

Prevalence studies in various places show evidence of an increase in the frequency of autistic disorders. The cause is not clear, and it is particularly not sufficiently clear whether this increase in prevalence means that the incidence of this disease in the population is increasing. For this reason and reasons outlined before by Professor Spitzer, a well designed epidemiological study is needed to explore associations and causation.

This study is planned to be performed in 8-9 countries in 3 continents. It was agreed that a large case-control study is the appropriate design to test a series of hypothesis on the risk of alleged risk factors mentioned by Spitzer, particularly the impact of mercury and MMR vaccine, controlling for all other potentially relevant factors. Apart from this, a large series of well-defined cases of autism will be available to study the natural course of autism and of certain subgroups in various places around the world and to generate further hypotheses. I some centers with relevant resources, genetical studies will be performed in collaboration with interested institutions.

The design of this complex epidemiological study consists of (a) an incidence study of new cases of autism with standardized methods in defined populations to provide data for compatible time trend analysis, and (b) the case-control study. The incidence study could be done in a 18-months period. It would be the first time that reliable incidence rates are available for phenotypically clear defined subgroups. The incidence study will also allow to establish the methods for the later case-control study, that are cross-culturally applicable under different conditions in several countries.

Most of the instruments to be applied in these studies have been drafted and wait to be tested in practice. The study infrastructure has been agreed upon in general. Many collaborating centers around the world have been identified and are ready to start the study as soon as funding issues are resolved.