Association Between Environmental Particulate Matter and Carpal Tunnel Syndrome in Patients Undergoing Hemodialysis

The deposition of β2-microglobulin induced by reactive inflammation causing carpal tunnel syndrome (CTS) is one of the complications of dialysis-related amyloidosis in maintenance hemodialysis (MHD) patients. Air pollution levels, especially particulate matter with an aerodynamic diameter of <2.5 mm (PM2.5), have significantly been associated with the elevation of systemic inflammatory markers. There is no previous research on possible associations between CTS and PM2.5.

This study enrolled 866 MHD patients treated at the outpatient HD centers. Senior neurologists diagnosed the presence of CTS. Air pollution levels were recorded by a network of 27 monitoring stations near or in the patients' living areas throughout Taiwan. The 12- and 24-month average concentrations of PM with an aerodynamic diameter of <10 and <2.5 mm (PM10 and PM2.5, respectively), sulfur dioxide, nitrogen dioxide, carbon monoxide, and ozone were included.

Multivariate logistic regression analyses showed that HD duration, the normalized protein catabolic rate (nPCR), hypoalbuminemia (albumin < 4 g/dl), and the mean previous 12-month environmental PM2.5 were positively associated with CTS; HD duration, nPCR, hypoalbuminemia (albumin < 4 g/dl), and the mean previous 24-month environmental PM2.5 were positively associated with CTS; HD duration, hypoalbuminemia (albumin < 4 g/dl), and previous 12-month PM2.5 excess days were positively associated with CTS; and HD duration, nPCR, hypoalbuminemia (albumin < 4 g/dl), and previous 24-month PM2.5 excess days were positively associated with CTS.

PM2.5 levels and PM2.5 excessing days were positively correlated with CTS.