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Screening for Disease


Introduction:

The screening of workers, or indeed of any members of the population, for the presence of disease is an important issue which needs to be critically considered, and never embarked upon lightly. It is worth noting a few principles, relating to the value of and justification for screening. The following questions should be asked before embarking on a screening programme: 
    In an occupational context the most important preliminary questions are: 
     
  • What ill-health could be caused by working in this context?
  • Is everything reasonable being done to prevent this ill-health?
  • Should health surveillance therefore be undertaken in relation to occupational ill-health?
  • ONLY once the above questions have been addressed, should one then consider other screening issues that are not directly work-related: 

    Is the condition important for individuals or the community? 
    Is there effective treatment for/management of the condition? 
    Is the condition's natural history, especially its evolution from latent to overt, understood? 
    Is there a recognisable latent or early stage? 
    Is there a valid and reproducible screening test? 
    Are facilities available for management of the positive findings, both true or false? 
    Is there an agreed management policy? 
    Does this management favourably influence the course of the disease? 
    Is the cost of case-finding and management acceptable in relation to the overall costs of health care? 
    Do the potential benefits to true positives outweigh the potential disadvantages for the false positives?

It is clear that any thoughtful person would pause before introducing general health screening in a workforce if such questions were considered. The chief disadvantage of 'health checks', apart from their grossly inefficient use of resources, is the harm done to individuals when insignificant findings lead to a series of unnecessary and sometimes dangerous investigations. When screening a healthy workforce, such false positives are likely greatly to outnumber true positives for whom useful intervention is possible. 

So-called 'executive medicals' are widely practised in some sectors of industry. Good evidence that they constitute a cost effective way of promoting health at work is lacking and one wonders whether they are more of a status symbol whereby the recipient can demonstrate to colleagues how highly he or she is prized by the organisation. Various reports, mainly from North American companies, have suggested that initiatives to improve lifestyle coupled with health screening appear to reduce the medical bills for which the firms are responsible. However, there are hardly any well designed and executed scientific studies that have measured the effectiveness of health promotion in the workplace either in terms of improved health or productivity. 

 

References

Acknowledgement: Part of this page has been adapted, with permission, from Practical Occupational Medicine (Copyright) - Arnold publishers.