Background: Vibration-induced white finger (VWF) is often assessed using the Stockholm Workshop Scale (SWS) and cold challenge plethysmography. However, long-term longitudinal studies using both methods are scarce.
Aims: To study the long-term course and prognostic factors of VWF assessed with the SWS and photoplethysmography (PPG), and to examine the effects of lifestyle on PPG score, regardless of VWF status.
Methods: Forty male construction workers were examined with a test battery and clinical examination in 1994 and 2016/17.
Results: At baseline, the sample comprised 27 workers with, and 13 without, symptoms of hand-arm vibration syndrome (HAVS). Thirty-five workers reported vibration exposure during follow-up. The mean age of the workers was 60 years (45-78) at follow-up. The paired t-test showed that PPG scores deteriorated from 1994 to 2017 in the 27 workers with HAVS in 1994 (mean difference 2.7 min, 95% confidence interval (CI) 0.2-5.2). However, there was no statistically significant change in SWS scores in these workers over time. Smoking and age were associated with PPG score deterioration. Vibration exposure during follow-up predicted SWS score deterioration: 1000 h of exposure predicted a deterioration stage of 0.09 (95% CI 0.03-0.16). Analysis of all 40 workers showed that 2017 PPG scores were associated with positive serum cotinine and self-reported smoking during follow-up.
Conclusions: Whereas age and smoking predicted a PPG deterioration, continued vibration exposure predicted worsening of white finger symptoms. The association of PPG score and smoking should be considered in diagnostic and prognostic factor evaluations.