S. A. Syurin, MD, DrMedSci.
Kola Research Laboratory for
Occupational Health, Kirovsk, Russia
Whole-body and hand-arm vibration-related health disorders
in High North miners
Introduction. In many occupations workers are exposed to
vibration of different types and parameters not encountered by man prior to the
industrialization of human society. In the modern Russian industry vibration-related
disorders (VRD) of vascular, neurological and musculoskeletal systems represent
one of the most common occupational health problems including temporary and permanent
disability [1].
The aim of the
study was to investigate the characteristic features of VRD in the Russian High North miners exposed to
whole-body vibration (WBV) or hand-arm vibration (HAV) and cold workplace environment.
Material and methods. The study included 667 VRD
cases which diagnostics was based on physical, functional and x-ray examination
of patients. According to the Russian vibration safety standard [2], exposure
to workplace WBV and HAV was measured by indices of vibration velocity (m/s)
and vibration load (dB). In addition, noise level (dBA), air temperature (0С), relative humidity (%) and velocity (m/s) were
measured for more complete characterization of workplace environment. Student's t-criterion and Pearson's correlation coefficient (r) were applied
for statistical analysis of the collected data.
Results. It was found that in Murmansk region (Russian
European High North) VRD were diagnosed in 20.1% of all patients suffering from
occupational health problems. The vast majority of diagnosed
cases of VRD (81.7%) were
observed in workers of the mining
industry. In the structure of occupational diseases, VRD ranked third being
inferior only to chronic respiratory diseases and neurosensory impairment of
hearing. The prevalence of VRD caused by mainly HAV was 1.84 times higher than that
due to mainly WBV: 432 and 235 patients, respectively. In the first
group, operators of various load-haul-dump vehicles and drilling rigs formed
the majority of patients. Drill operators, tunnelers and mine-face workers dominated in the latter group.
The
early adverse health effects (stage 1 of the Russian classification for VRD)
caused by WBV manifested themselves in angiodystonic syndrome and sensori-vegetative
polyneuropathy of the lower extremities. In the stage 1-2, there were
additional more advanced health disorders:
polyradiculoneuropathy, secondary lumbar-sacral radicular syndrome due
to osteochondrosis of vertebral column, cerebral angiodystonic syndrome. Severe
health disorders (belonging to the stage 3) did not develop in the workers who
were under regular medical surveillance. VRD caused by WBV were diagnosed first
at the mean age 49.9±0,5 yrs (29-70 yrs) and the mean duration of employment 24.4±0.7 yrs (5-44 yrs). The distribution of
VRD according to severity of clinical symptoms and functional disorders was the
following: stage 1 – 71 (30.2%), stage 1-2 - 79 (33.6%) and stage 2 - 85 (36.2%)
workers. There was a correlation between severity of VRD and the patients´
age (r=+0.29, p<0.01) and duration of employment (r=+0.30, p<0.01).
Exposure
to HAV led to the development of angiodystonic syndrome and sensori-vegetative
polyneuropathy of the upper extremities, degenerative changes of the
locomotorium of the upper part of body, cervicobrachial plexopathy. VRD due to HAV
were found first at the age 42.7±0.4 yrs (25-59 yrs) and duration of
employment 16.6±0.3 yrs (4 – 36 yrs).
So their development took place at a significantly earlier age (p<0.001) and after shorter duration of
employment (p<0.001) as compared to
exposure to WBV. The staging of VRD due to HTV was similar to that caused by
WBV: stage 1 – 151 (35.0%), stage 1-2 - 133 (34.0%) and stage 2 - 148 (34.3%)
workers. Severity of pathological changes induced by HTV correlated with
patients´ age (r=+0.28, p<0.01) and duration of work (r=+0.32, p<0.01).
The operators of hand-held vibratory
tools used in Russian mining industry may be exposed to vibration levels significantly
higher than excepted limit values (LV): vibration velocity may reach 2.30 m/s
(LV 2.00 m/s) and vibration load – 145 dB (LV 126 dB). As a rule, operators of
various vehicles and machines were exposed to WBV with action levels within excepted
LV. Vibration velocity did not exceed 0.45 m/s (LV 0.28-0.56 m/s) and vibration
load – 95 dB (LV 109-115 dB). In addition, operators of hand-held vibratory
tools were exposed to contributing occupational hazardous factors such as higher
noise levels and worse protection against workplace cold. For operators of
hand-held vibratory tools maximum noise levels reached 113 dBA (LV 80 dBA). The
cold workplace environment was due to low air temperature (4-100 С), high air relative humidity (86-100%) and flow of
cold air caused by natural and artificial ventilation in the mines (up to 1.2
m/s).
Analysis
of the obtained data suggests the following explanation of the earlier and more
frequent development of VRD in operators of hand-held vibratory tools: 1) higher
intensity of HAV as compared to WBV; 2) additive effect of cold-related and
noise-related disorders of vascular, neurological and musculoskeletal systems;
3) possible higher susceptibility to vibration and cold of upper extremities
and upper part of the human body.
Conclusion.
Health problems arising from whole-body and hand-arm vibration are highly
prevalent among industrial workers in the Russian High North. HAV causes
earlier and more frequent occurrence of health disorders as compared to WBV. To
reduce or eliminate adverse effects of vibration on exposed workers there is a
need for improvement of technical characteristics of hand-held vibratory tools
and various load-haul-dump vehicles in combination with strict observance of
occupational safety rules. On the other hand, current situation requires the
implementation of more efficient medical methods of prevention and treatment of
the cited above VRD.
References
1. Artamonova V.G.,
Mukhin N.A. Occupational Diseases. Moscow: Meditsina Publishing House. 2006: 125-153
(in Russian).
2. System of Labor
Safety Standards. Vibration Safety. General Requirements. State Standard
12.1012-90. Moscow. 1990: 1-44 (in Russian).