The long-term effects of occupational exposure to vinyl chloride monomer on microcirculation: a cross-sectional study 15 years after retirement.

OBJECTIVES

To assess residual long-term microcirculation abnormalities by capillaroscopy, 15 years after retiring from occupational exposure to vinyl chloride monomer (VCM).

DESIGN

Cross-sectional study.

SETTING

Allier, one of the major areas of polyvinyl chloride production in France.

PARTICIPANTS

We screened 761 (97% men) retired workers exposed to chemical toxics. Exposure to chemicals other than VCM excluded potential participants.

PRIMARY AND SECONDARY OUTCOME MEASURES

These participants underwent a medical examination including a capillaroscopy, symptoms of Raynaud and comorbidities, as well as a survey to determine exposure time, direct or indirect contact, type of occupation, smoking status and time after exposure. A double blind analysis of capillaroscopic images was carried out. A control group was matched in age, sex, type of occupation.

RESULTS

179/761 retired workers were only exposed to VCM at their work, with 21 meeting the inclusion criteria and included. Exposure time was 29.8±1.9 years and time after exposure was 15.9±2.4 years. Retired workers previously exposed to VCM had significantly higher capillaroscopic modifications than the 35 controls: enlarged capillaries (19% vs 0%, p<0.001), dystrophy (28.6% vs 0%, p=0.0012) and augmented length (33% vs 0%, p<0.001). Time exposure was linked (p<0.001) with enlarged capillaries (R(2)=0.63), dystrophy (R(2)=0.51) and capillary length (R(2)=0.36). They also had higher symptoms of Raynaud (19% vs 0%, p=0.007) without correlation with capillaroscopic modifications.

CONCLUSIONS

Although VCM exposure was already known to affect microcirculation, our study demonstrates residual long-term abnormalities following an average of 15 years' retirement, with a time-related exposure response. Symptoms of Raynaud, although statistically associated with exposure, were not related to capillaroscopic modifications; its origin remains to be determined.