INTERNATIONAL ARCHIVES OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH
Abstract
Objectives To investigate prospectively the relation
between vibration-induced white finger (VWF), exposure
to hand-trasmitted vibration (HTV) and the cold response
of digital arteries in users of vibrating tools.
Methods Two-hundred and sixteen HTV workers and 133
control men of the same companies underwent initially a
medical examination and a standardised cold test with
measurement of the change in finger systolic blood pressure
(FSBP) after finger cooling from 30 to 10C. They
were re-examined 1 year later. Tool vibration magnitudes
were expressed as frequency-weighted and unweighted
r.m.s. accelerations. From the vibration magnitudes and
exposure durations, alternative measures of cumulative
vibration dose were calculated for each HTV worker,
according to the expression: dose ¼ Pami
ti, where ai is the
acceleration magnitude on tool i, ti is the lifetime exposure
duration for tool i, and m = 0, 1, 2 or 4.
Results Among the HTV workers, the initial prevalence
and the 1-year incidence of VWF were 18.1 and 1.7%,
respectively. At the first examination, the HTV workers
with moderate or severe score for VWF showed a significantly
increased cold reaction in the fingers when
compared with the controls and the HTV workers with no
vascular symptoms. At the follow-up, the controls, the
asymptomatic HTV workers, and the prevalent cases of
VWF did not show significant changes in the cold response
of digital arteries. A deterioration of cold-induced digital
vasoconstriction was found in the incident cases of VWF.
In the HTV workers, vibration doses with high powers of
acceleration (i.e., dose ¼ Pami
ti with m[1) were major
predictors of the vasoconstrictor response to cold at the
follow-up examination.
Conclusions The measurement of FSBP after local
cooling may be a helpful objective test to monitor prospectively
the change in vibration-induced vascular
symptoms. The findings of this longitudinal study suggest a
dose–effect relationship between cold-induced digital
arterial hyperresponsiveness over time and measures of
cumulative vibration exposure. In the controls, the cold
response of the digital arteries was stable over 1-year follow-
up period.