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We read the paper by Compston et al on bone loss in Gulf veterans1 with concern and interest. However, if taken to represent the problems of unwell Gulf veterans it is open to serious misinterpretation because of problems in design, factual accuracy, and certain conjectures.
The 17 cases are potential litigants who are highly unlikely to be representative of the Gulf veteran population. Apart from very brief sociodemographic details, smoking and alcohol consumption histories, no clinical information is given about the indications for bone biopsy except that 16 complained of unspecified arthralgia and other musculoskeletal symptoms. The 13 controls were taken from a study, reported 20 years ago, involving bone biopsies on civilians undergoing minor surgery and are thus not a comparable group. Furthermore, investigators were not blind to case/control status, allowing for observer bias. Therefore, no general conclusions about Gulf veterans’ morbidity can be inferred from this work.
The findings of reduced bone formation are said to be heterogeneous but bone histology was normal in six cases. No clinical histories suggesting bone disorder are reported and the presence of osteoporosis is denied. We agree that the clinical relevance of these findings is unclear, but would point out that bone loss occurs in several conditions in which reduced activity is a feature, including depressive illnesses and other multisymptom disorders,2,3 which are not uncommon in Gulf veterans.4 Exclusion of these and other conditions associated with bone loss are necessary steps before these findings are associated with service in the Gulf.
The attribution of these findings to possible exposures in the Gulf deserves comment. Lifestyle changes are briefly discussed but no other possible clinical explanations are offered. Instead, the authors point to associations with very dubious exposures to organophosphate (OP), compounds such as pesticides and sarin. What exactly was the basis of the statement of obvious OP pesticide spraying and why was it accepted so uncritically? Sarin is an odourless, colourless vapour whose detection on military operations is only possible by either patients experiencing symptoms or special detection equipment. There was no confirmed offensive use during the Gulf conflict or subsequently. Given the toxicity of sarin and the fact that no deaths from or cases of OP poisoning were seen during the Gulf conflict the uncritical acceptance of a statement of awareness of sarin exposure is irresponsible. To claim similarities with findings in agricultural workers with chronic OP exposure from sheep dipping is equally unjustified because any possible exposure histories would be quite dissimilar, usually involving several years of exposure. Immunisation history is a red herring. A search of MEDLINE reveals no evidence to connect osteoporotic conditions with immunisations. It is true that the reversible anticholinesterase pyridostigmine was used as a nerve agent pretreatment but doses were small. If this was a factor in the bone changes found would one not expect to see a similar picture in patients with myasthenia gravis? Clearly, there are many alternative explanations for the reported findings, which may of course have no clinical relevance at all.
(The authors are all employed by the Ministry of Defence. The views expressed here are their own and do not represent those of the Ministry of Defence.)