How can we approach a disease as hard to pin down as autism, asks Dr Karine Nohr
In the biological study of the rising prevalence of autism, the new paradigm suggests that autism is a systemic disease with gastrointestinal, metabolic, immune, and nutritional abnormalities.
There is evidence that the problems are not limited to the brain, that there may be widespread inflammation, which is worse in vulnerable areas.
Genetic concordance studies suggest a significant genetic factor in it's aetiology, but the risk is relative and not absolute (i.e. no specific genetic abnormality confers a 100% risk of the disorder). So ecological factors must come in to play.
Evaluating those physical environmental factors is complicated (and I'm not even mentioning the psychosocial aspects of environment at this point). Our current standards of risk benefit analysis are that you compare the risks with the benefits and you presume safety until proven otherwise.
There are 58,000 unregistered chemicals in the market place. New chemicals are being found all of the time. Many chemicals are ‘grandfathered' in as safe, because they have been around a long time. But a ‘precautionary principle' would be a safer principle for new chemical or technologies, whereby proof of safety is required before they are accepted or implemented.
There are different levels at which chemicals can have an impact. At worst, they can kill cells. At lesser levels, or lesser exposure, they may imitate the body's own hormones or signaling mechanism and change the way in which the body functions, in a way that the body would not have done if left to its own devices.
Furthermore, combinations of low levels of chemicals can have greater effects than either one alone, or novel effects that one alone would not have had. To further complicate matters, the timing of the exposure may be critical, as may be the individual's genetic vulnerability.
Toxins can impact mitochondria, and some pesticides, for example, have been observed to block particular steps in mitochondrial metabolism. So if you are exposed to multiple environmental noxious substances, your mitochondria may get a little torpid. This might cause low muscle tone, or fatigue. The system is depressed.
This might not be sufficiently so for a clear diagnosis of a recognised disorder, but it may be enough to slow things down. There may be a problem with the more sophisticated networks. In the brain of the infant, for example, where a lot of energy is required, or where a lot of co-ordination between different types of network is required, particularly in the early years, and those networks that are the most sophisticated, such as those for language, or soicialisation or behavioural flexibility, will have the greatest vulnerability to those toxins.
And so the loss of elegant pathways and systems could lead to a person resorting to easier, less challenging functioning, such as restricted repetitive and stereotyped patterns of behavior, interests and activities, that are seen in autistic children.
In the medicine of this new century, do we need to be more mindful than we have been to date, of the way that we are treating our fragile planet and the harm that we may be causing, not only to the planet itself but to the creatures, such as ourselves, that are exposed to these multitudes of toxins?
There have been recent studies finding a strong association between autism and inflammation and oxidative stress in the brain, certainly inflammation is increasingly considered to be a major factor in the aetiology of many common diseases, such as CVD or cancer or asthma.
Many disease entities have abnormalities that are fairly generic, rather than specific to one disease. Many diseases are on a continuum in terms of severity, and the level at which one might label a patient with a diagnosis might be arbitrary, or at least relative rather than absolute.
We are therefore talking about patterns, rather than rules. And thus we have a model of medicine that is holistic, and that demands consideration of individualilty within an Integrative approach.
Dr Karine Nohr is a GP in Sheffield
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