Distal pain and carpal tunnel syndrome diagnosis among cashiers: a longitudinal study

To estimate in a longitudinal study the yearly incidence of carpal tunnel syndrome (CTS) in a cohort of women working as cashiers. A total of 198 cashiers, belonging to a cohort investigated in 2011-2012 for arm pain, were screened for re-assessment in 2015 (at least 40 months from the first examination), and 156 women had complete demographic, personal and working data allowing to be included in this study. On the basis of self- and clinician-administered questionnaires investigating the presence of CTS, all symptomatic patients underwent clinical and neurophysiological [nerve conduction studies (NCS) of median and ulnar nerves] assessments. NCS confirmed the presence of CTS in 17 out of 149 workers; however, seven of them already received the diagnosis of CTS at the previous assessment in 2011-2012, leading to an overall incidence of new cases equal to 7.0%. Cumulative working time at the cashier of the women with CTS in the period 2012-2015 was highly variable (1744-4479 h) without an evident association with the severity of CTS. No differences in general demographic data were found in the women with vs. without CTS. Comorbidities potentially associated with increased risk of CTS were present in 21 women in the entire cohort (14.0% of the population, 40.0% in the subgroup of women with newly assessed CTS). Overweight/obesity and hypothyroidism were the most frequent comorbidities. The results of this prospective study showed that the annualized incidence of CTS in our population of cashier was 2.0%; 40% of the new CTS cases had comorbidities.