Development of a high-utility, evidence-based system of occupational health surveillance for divers

Abstract

Routine health surveillance, and specifically routine occupational health surveillance in the form of a medical examination, is commonplace, and for many workers is mandatory. Perpetuation of workplace policies that mandate testing such as ‘the annual medical’ is influenced by a variety of ‘stakeholder’ agendas. However, evidence of the utility of such testing is lacking. The primary aim of this research was to find evidence to clarify whether widely accepted basic components of the current occupational diver health surveillance programme are ‘fit for purpose’ and actually enable an appropriate determination of fitness to work. The working hypothesis underlying the studies that comprise this thesis was that there is no evidence to support many of the current mandatory requirements of occupational health surveillance or fitness-to-work determination. A secondary aim was to propose a justifiable and logical health surveillance system for this particular group of workers, professional divers, with possible broader applicability to other categories of workers. Using the case of professional divers as an exemplar, the various components of the routine health surveillance and certification process were examined for their contribution to determining fitness to dive. First, the only two mandatory investigations of the physical examination are tests of lung function and hearing. The value of these investigations was assessed using three longitudinal studies seeking evidence of any correlation between professional diving and clinically significant deterioration in either lung function or hearing. Second, a postal survey was conducted to determine whether the doctors who perform dive medical examinations were able to accurately determine fitness to dive based on vital health information. Third, diver satisfaction with the current certification system was determined using an internet-based survey of registered divers over a 12-month period. Fourth, a qualitative study examined diver interpretations and the value of the individual component questions in the current annual health questionnaire. Fifth, the utility of the current surveillance system was examined using two audits spanning different 5-year intervals. These audits involved analysis of divers’ health records to iv determine whether the vital information leading to diver disqualification came from the annual health questionnaire or from the medical examination. Finally, an audit of ex-divers was conducted to determine whether health-related issues were a significant factor in the high rate of attrition of professional divers. The results demonstrated that neither lung function nor hearing was significantly affected by long-term professional diving activity. The doctors who conduct medical assessments of divers were found to perform little better than chance in determining fitness to dive. Most divers were satisfied with the current health certification/surveillance system. Dissatisfaction was mainly related to cost and a limited understanding of the reasons for the various facets of the system. All questions comprising the annual health questionnaire were correctly interpreted by divers, although some questions were considered of low value by experts. Audits of the current system concluded that routine physical examination or investigations did not add significantly to the value of the health questionnaire in uncovering those conditions incompatible with, or requiring modification of, ongoing professional diving. Finally, health-related factors did not appear to be a significant determinant of diver attrition, strongly validating the modifications thus far to the health surveillance system. The over-all conclusion to be drawn from this body of research is that routine medical examinations of professional divers are unreliable and unnecessary. A modified surveillance programme, centred on a health questionnaire, has been proposed for this specialised group of workers, with the aim of providing considerable savings of time and money, but no increase in health risk. Other groups of workers are likely to be similarly affected by health surveillance protocols in need of revision for lack of a reliable supporting evidence base.