[Work-related carpal tunnel syndrome. Motivations and results of a surveillance system]

Current statistics show that work-related carpal tunnel syndrome (CTS) has been increasing constantly over the last ten years. Nevertheless, available data on the incidence of CTS in the general population and on the occupational proportion of the aetiology of this disease suggest considerable underreporting of work-related cases, which reflects on the number of cases reported to INAIL (National Insurance Institute for Industrial Accidents) and does not give an accurate epidemiological picture of their origin and distribution. For this reason, in the course of a prevention programme of upper limb disorders due to biomechanical overload, a second experiment concerning CTS surveillance system was carried out by collecting self-reported information via postal questionnaires. The aim of this study was to estimate the prevalence of work-related cases in the selected group of the general population and to identify work tasks and factories with significant risk of CTS clusters.

From the hospital discharge lists of the Province of Brescia for 2001 and 2005, 1558 surgical cases were selected, aged 18-65 years, excluding housewives (nearly 25% of the total); thus 637 surgical cases were included in the study (68.6% female and 31.4% male).

Obesity frequency was observed to be higher in the sample than in the general population. This was not the case for diabetes. The probability of surgical CTS cases attributable to occupational exposure was estimated by dividing the 637 cases into three exposure categories:probable, possible and improbable with results of respectively 44.4%, 36.6% and 19%; in the first category, the frequency among females was 78.8%. The CTS cases among females less than 40 years old was 40% in the probable exposure category versus 10% into the improbable exposure category. In the latter category, the prevalence of concomitant hand tendinitis was 11% versus 22% in the probable exposure category. Obese patients fell into the three occupational risk groups in the same proportion. Among the 283 STC cases considered as probable occupational exposure cases, only 11 were reported as required by law to the Occupational Health Service. Whereas a number of work tasks and work sectors with high risk factors were confirmed, there were relatively few factories with a possible presence of clusters, probably due to the small sample size compared to the general population and to the density of the factories potentially at risk. The epidemiological surveillance thus carried out provided more evidence confirming the serious underreporting of the work-related STC cases in a highly industrialised province and also provided useful information on the local situation regarding high-risk occupations, which need to be addressed via interventions of primary prevention should, possibly with greater involvement of the occupational physicians.