[Carpal tunnel syndrome: example of assessment of the role of occupational exposure based on self-reported data].

Background: The prevalence of surgical cases of carpal tunnel syndrome (CTS) tends to increase in the general population in Italy. Nevertheless, it is still unclear what percentage of CTS is attributable to occupational exposure, to ergonomic or psychosocial factors. Moreover, the problem of obtaining a reliable definition of occupational exposure in the absence of direct observation and measurement in the workplace remains unsolved. Piedmont (north-western Italy) is one of the Italian regions with the highest number of musculoskeletal disorders recognized and compensated as work-related. The aim of this study was to estimate the proportion of work-related CTS surgical cases, based on self-reported exposure data.

Methods: An interview-based questionnaire included items on medical history, workplace exposures and non-occupational risk factors for CTS. The study was carried out between June 2003 and November 2004. A total of 260 adult patients (aged 18-65 years) were interviewed. An evaluation of the questionnaires was made by 3 occupational physicians, assigning every patient a probability score of occupational aetiology. Seventy-four per cent of the sample were female; the mean age was 48.4 years.

Results: Seventy-one percent of the patients reported bilateral CTS. Occupational exposure preceded the onset of CTS symptoms for 184 patients. The probability that CTS was work-related was estimated as high for 66 patients (26% of the sample). Agreement among examiners, evaluated using the kappa statistic, was good.

Conclusions: Despite the limitations of the study, the number of cases attributable to occupation was much higher than the number of diseases reported to INAIL (National Institute for the Insurance of Industrial Accidents), which suggests that there is substantial under-notification in Italy.