Organophosphates: Questions to COT (Hansard, 7 July 1998)

§ The Minister of State, Department of Health (Baroness Jay of Paddington)

The questions proposed inOfficial Group on OPs—Report to Ministers are as follows:

(i) What evidence is there that it is possible to develop long-term symptoms from recognised acute organophosphate poisoning?
(ii) What evidence is there that an unrecognised acute poisoning incident could cause long-term effects?
(iii) What evidence is there that people can develop chronic symptoms from low-level exposure to organophosphates?
(iv) Does the picture become clearer if the studies to which the Institute of Environment and Health report refers are divided up between those which purport to show objective or subjective end points?
(v) Does the committee agree that a number of the studies discussed in the report had methodological flaws? If so, what were the flaws and how serious were they?
(vi) Is it possible, nonetheless, to deduce anything from these "flawed" studies?
(vii) Does the committee agree with the evaluation of the five particular studies suggested by Dr. Ray as being the most reliable?
(viii) Is it possible that the chronic symptoms and signs from low-level exposure could be different from delayed symptoms from acute exposure?
(ix) Have the epidemiological studies that have been carried out on the effects of low dose exposure to organophosphates been of the right design and of sufficient statistical power to detect a biologically significant effect?
(x) Is OP induced delayed polyneuropathy (OPIDP) relevant to the controversy about organophosphate sheep dips and does this aspect of the problem need further investigation?
(xi) What evidence is there of variable individual susceptibility to the extent that some people are more likely to suffer ill effects from OP exposure than others and could this account for long-term effects?
(xii) Are there indications of possible mechanisms other than the inhibition of acetylcholinesterase at work?
(xiii) Is it the committee's view that the animal models being used to investigate mechanisms of effects of OPs are the right ones to predict how OPs will affect humans?
(xiv) What recommendations would the committee make for further research?
(xv) Is it the committee's view that those epidemiological studies identified to be sufficiently well-conducted could be used as the basis for a meta-analysis?
(xvi) How do the symptoms experienced by those who attribute illness to OPs relate to effects observed in the epidemiological studies?

(These questions are given on pages 31 and 32 of Official Group on OPs—Report to Ministers.)

This issue was put to the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT), which has set up a working group to discuss the topic. The questions were presented to the sub group at its first meeting (on 22 May). Some refinements were suggested, but without altering the substance of the questions. In addition, the group may add to these questions during their deliberations.