Incidence of Raynaud's phenomenon in relation to hand-arm vibration exposure among male workers at an engineering plant a cohort study

The baseline population consisted of 94 office and 147 manual workers at an engineering plant. Raynaud's phenomenon (RP) was assessed at baseline and at follow up (at 5, 10 and 15 years). A retrospective and a prospective cohort analysis of data were done. Hand-arm vibration exposure dose was defined as the product of exposure duration and the weighted hand-arm vibration exposure value according to ISO 5349-1.The retrospective/prospective incidence of Raynaud's phenomenon was 16/14 per 1000 exposure years among exposed and 2.4/5.0 per 1000 years among the not exposed. The retrospective dose response curve based on 4 dose classes showed that class 2, 3 and 4 had similar response and showed higher incidence than the not-exposed. The dose with RP response to hand-arm vibration corresponded to a 10 year A(8) value between 0.4–1.0 m/s2.The results indicate that the EU directive on an action value for hand-arm vibration of 2.5 m/s2 is not too low. Rather, it suggests that employers should take on actions even at exposure values of 1 m/s2A(8).Raynaud's phenomenon (RP) is cold provoked episodes of well-demarcated distal blanching (whiteness) in one or more fingers [1,2]. It occurs idiopathic more often among women than men [3]. Vibration induced white finger (VWF) is defined as first appearance of RP after start of professional exposure to hand-arm vibration and no other probable causes of RP [1,2]. The pathogenic mechanism of VWF is not completely understood but digital artery vasospasm is a probable cause. Both central and local mechanisms have been suggested for this vasospasm. The central mechanism may be an overactivity of the central sympathic nervous system and the local a digital vascular fault [1]. Anamnestic diagnostics by medical interview and questionnaire are widely accepted [1]. Cold induced digital artery vasospasm can also be measured by cold provocation tests [1].Despite the number of studies published concerning VWF, the form of the exposure-response relat