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Originally Posted by deek
CT, you are absolutely spot on regarding your comments about a scientist in Canada if he was asked the same question in respect of the reported health complaints in Canada (which appear to be zero). However, it would appear you are taking this out of context. If the scientist in Canada has no health complaints to study then he will have difficulty forming an opinion without referring to the learned journals.
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No deek, if a scientist in Canada has looked at the epidemiology and determined that no apparent health effects are occurring in Canada, despite the very large area of canola grown in Canada, he or she would have every right to form an opinion that “they believed canola crops did not increase the prevalence of allergy symptoms in the local population who live in close proximity to the crops”. What they might understand from the literature is some concern in Scotland that people living near canola crops reported a small increase in respiratory symptoms such as sneezing cough and headache among a small number of individuals. This is correlation, not causation. The fact that the villagers reported symptoms coinciding with flowering of canola may be significant or it may be that canola flowers are so visible that their minds put 2 and 2 together. Humans are very good at finding patterns, even when no such patterns exist. The fact that reports of respiratory symptoms (I should point out that none of the symptoms reported are specific to allergies which is immunological) occurred in a village near canola crops in Scotland may have more to do with the specific environment in Scotland rather than the crop per se. This could include specific fungal spores or factors that arise because of local environmental conditions that don’t occur elsewhere.
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Originally Posted by deek
In a situation like this, the scientist, if asked to form an opinion, would have to refer to previously published studies in other parts of the world (in the UK) in order to arrive at an informed opinion.
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Not necessarily so. You are assuming that no information is available elsewhere. But there is and it is all negative. I should point out that the evidence from Scotland is very slight and does fall squarely in the region of self-reported correlation. This information has been around for over a decade now and no causative effect has been identified.
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Originally Posted by deek
If there is any doubt (based upon previously published findings) regarding potential risks to human health then, I believe, precautions should be implemented as a matter of common sense. I do not wish to draw parallels with the precautionary principle because I’m sure you are well versed with this. However, as forfismum says, public health authorities should be seen to take adequate steps in order to ensure the safety and well-being of its citizens. Failure to do so would be a breach of public duty and perhaps negligent.
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However, a risk assessment would determine that the highest risk of canola allergy would be from grain dust. There is quite a lot of evidence that this happens. In fact it is a very similar situation to baker’s allergy. The risk management would be to have grain handlers and farmers wear masks when handling the grain. Problem solved. Risk assessment considers both the probability of a situation occurring, the potential hazard that might result and what can be done to minimize the risks. None of the symptoms reported by Parratt et al. or Souter et al. actually carry any significant hazard to people. They might be uncomfortable for those who get them for a short period of time, but you get the same symptoms from common cold. Secondly the increase in symptoms was very small and could not be connected to the cultivation of the crop. Studies elsewhere have failed to find a connection.
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Originally Posted by deek
I don’t think this thread is the correct location for a detailed discussion on causal factors relative to oilseed rape crops, however, I would say that the over-whelming scientific opinion is that more research is required in order to bring resolution to these public health concerns.
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Given that this seems to only be an issue in Scotland, a country that grows very little canola, I would suggest that a study to look at the impact of canola and other factors in that region needs to be conducted. I would also suggest that even the studies from Scotland indicate the public health concerns are slight. Perhaps any funding could be better spent on public health concerns of greater significance?
And while we are quoting the literature (OK, we are quoting editorials) perhaps these might be apt?
Murphy D.J. (1999 ) Is rapeseed really an allergenic plant? Popular myths versus scientific realities. Immunology Today 20: 511-1514.
“Coincidental with the expansion of rapeseed cultivation, there have been increases in the number of reported cases of asthma and other conditions related to allergenicity and irritancy. This has led to the creation of a powerful popular perception that rapeseed cultivation is linked to increasing allergic symptoms, particularly among populations in the vicinity of the crop[3]. Although this perception is supported by little scientific evidence, it continues to be received wisdom in both the popular and scientific press.”
"It is interesting that this extremely negative perception of rapeseed appears to be overwhelmingly concentrated in the UK. For example, in a study of 4468 patients with suspected inhalant allergy in Austria, only four individuals blamed rapeseed for their condition [16]. By contrast, a relatively large proportion of individuals with similar symptoms in the UK were inclined to attribute these to rapeseed [27]. This was particularly true if they lived or worked in the vicinity of rapeseed crops. No similar concerns have been expressed in countries such as France or Germany, despite the fact that each of these countries produces well over twice as much rapeseed as the UK.”
Hemmer, W. (1998 ) The health effects of oilseed rape: myth or reality?
No clear evidence that it has adverse effects on health. British Medical Journal 316: 1327-1328.
“Higher prevalences of headaches, cough, and wheezing—at the borderlines of statistical significance—have been described from areas of oilseed rape cultivation,10,12 but symptom scores were generally low in these studies and no correction was made for other potential factors, such as climate, that might have explained the observed differences.”
“Only in Britain has oilseed rape been suspected by the public of causing ill health effects. In other rape growing countries, such as France, Germany, Denmark, and Canada, no such public concern against oilseed rape exists. Is there some prejudice because the expansion of this crop is subsidised by the European Union, or do people simply dislike its intense smell and flashy yellow flowers? Science must never ignore potential health hazards, but so far there is little evidence to incriminate a versatile crop of economic importance as a cause of ill health.”
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Originally Posted by deek
It begs serious questions regarding the integrity of those conducting environmental risk assessments in respect of the cultivation of GM crops. Do you not think it rather strange CT, that substantial equivalence is conveniently forgotten about when evaluating the risks to human health in respect of GM canola/oilseed rape? Or are you going to tell me that the corporate sponsors have engineered out this undesirable trait? No doubt (as I type) they are busy splicing away right now trying to find a solution to a problem that allegedly does not exist.
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deek, this is indeed a strange remark. In all the risk assessments of GM canola I have seen, substantial equivalence is a key component. In fact substantial equivalence is one of the things that gets quite a number of the anti-GM campaigners frothing at the mouth. Yet you are suggesting it doesn’t get used?
I very much doubt anyone is working on changing canola to reduce the symptoms observed in Scotland. As yet there is no cause identified for these symptoms, so no one would know what to change. Secondly, these symptoms appear to occur in only a miniscule region of the canola-growing landscape. Thirdly, EU politics is such that even if a crop were to be developed, permission to grow it in Scotland would never eventuate.