Hand-armvibration syndromeThe term hand-arm vibration syndrome is used to refer to the collection ofperipheralneurological, vascular, and musculoskeletal symptoms that are recognised

Occupational and Environmental Medicine 1994;51:603-61 1

Hand-arm vibration syndrome and dose-responserelation for vibration induced white finger amongquarry drillers and stonecarvers

M Bovenzi and the Italian Study Group on Physical Hazards in the Stone Industry

AbstractObjectives-To investigate the occur-rence of disorders associated with thehand arm vibration syndrome in a largepopulation of stone workers in Italy. Thedose-response relation for vibrationinduced white finger (VWF) was also studied.Methods-The study population con-sisted of 570 quarry drillers andstonecarvers exposed to vibration and 258control stone workers who performedonly manual activity. Each subject wasinterviewed with health and workplaceassessment questionnaires. Sensori-neural and VWF disorders were stagedaccording to the Stockholm workshopscales. Vibration was measured on a rep-resentative sample of percussive androtary tools. The 8 h energy equivalentfrequency weighted acceleration (A (8))and lifetime vibration doses were calcu-lated for each of the exposed stoneworkers.Results-Sensorineural and musculo-skeletal symptoms occurred more fre-quently in the workers exposed tovibration than in the controls, but trendstatistics did not show a linear exposure-response relation for these disorders. Theprevalence ofVWF was found to be 30'2%in the entire group exposed to vibration.Raynaud's phenomenon was discoveredin 4*3% ofthe controls. VWF was stronglyassociated with exposure to vibration anda monotonic dose-response relation wasfound. According to the exposure data ofthis study, the expected percentage ofstone workers affected with VWF tends toincrease roughly in proportion to thesquare root of A(8) (for a particularexposure period) or in proportion to thesquare root of the duration of exposure(for a constant magnitude ofvibration).Conclusion-Even although limited to aspecific work situation, the dose-response relation for VWF estimated inthis study suggests a time dependencysuch that halving the years of exposureallows a doubling ofthe energy equivalentvibration. According to these findings,the vibration exposure levels currentlyunder discussion within the EuropeanCommunity seem to represent reason-able exposure limits for the protection ofworkers against the harmful effects ofhand transmitted vibration.

Adverse health effects resulting from the useof vibrating tools in the stone industry havebeen reported since the beginning of thiscentury. In 191 1, Giovanni Loriga, anItalian physician, first described the occur-rence of episodes of tingling, numbness, andwhiteness in the fingers and hands of stoneand marble cutters and carvers who used bar-rel shaped air hammers without a handle andthrottle valve.' Later in 1918, Alice Hamiltonreported that 89-5% of 38 limestone cutters ofBedford, Indiana, United States, had attacksof finger blanching (defined as "spastic ane-mia affecting the arterioles of the fingers andhands")2 resembling the digital ischaemicphenomenon described by the French physi-cian Maurice Raynaud in 1862. A personalreview of the available scientific literatureshowed that in the last 80 years about 20 epi-demiological surveys of vibration induced dis-orders among stone workers have beenperformed. 1-12

Italy produces more stone than any othercountry in the world (7-2 million tons in1991). In Italy great varieties of ornamentalstones such as marble, travertine, porphyry,granite, and serpentine are excavated in thequarries and processed in the mills. In recentdecades there has been limited implementa-tion of technical measures aimed at reducingthe risk from exposure to excessive vibrationin the stone industry. Taylor et al who revis-ited the limestone quarries of Bedford after a60 year interval,7 found that no change in thedesign of the air hammers used by the stone-cutters had taken place since the 1918Hamilton survey. We did similar observationsin a previous study of travertine quarry drillersand stonecutters who mainly operated percus-sive pneumatic tools.'0 In the present study,the occurrence of hand-arm vibration syn-drome was investigated in a large sample ofquarry drillers and stonecarvers working inseveral districts of Italy. The term hand-armvibration syndrome is used to refer to thecollection of peripheral neurological, vascular,and musculoskeletal symptoms that arerecognised to affect the upper extremities ofworkers exposed to vibration. As thecharacteristics of vibration exposure in thestone industry were found to be stable overtime, mainly with respect to the type anddesign of the pneumatic tools used by thestone workers, the relation between vibrationexposure and the various components of thehand-arm vibration syndrome was alsostudied.

(Occup Environ Med 1994;51:603-61 1)

Institute ofOccupational Health,University ofTrieste,c/o Centro Tumori,Via delta PietA 19, 1-34129 Trieste, ItalyM BovenziUO TSLL, USSL 21,Morbegno, SondrioS CerriSMML, USL CentroSud, BolzanoA Merseburger

SPISLL USL30. SienaL ScattoniI PintoUO TSLL, USSL 58,Domodossola, NovaraV RoncaSPISLL, USL 3,Pietrasanta, Lucca,A NucciSMPIL, USL 28,BolognaS MattioliULSS 26, Bussolengo,VeronaC ZanderigoCorrespondence to:Dr Massimo Bovenzi,Istituto di Medicina delLavoro, UniversitA diTrieste, c/o Centro Tumori,Via della Pietk 19, 1-34129Trieste, Italy.Accepted 16 May 1994

603

on October 2, 2020 by guest. P

rotected by copyright.http://oem

.bmj.com

/O

ccup Environ M

ed: first published as 10.1136/oem.51.9.603 on 1 S

eptember 1994. D

ownloaded from

http://oem.bmj.com/

Bovenzi and the Italian Study Group on Physical Hazards in the Stone Industry

Materials and methodsSUBJECTSThe study population consisted of 828 activestone workers employed in nine districts ofNorth and Central Italy, where quarrying andstonecarving have an important role in thelocal economic life. The group exposed tovibration included 145 quarry drillers whoused rock breakers and rock drills and 425stonecarvers processing stone blocks in themills. Of the stonecarvers, 188 (group A) usedonly rotary tools (angle grinders), and 237(group B) used both rotary and percussivetools (angle grinders and light stone ham-mers). The remaining 258 stone workersformed the control group, which consisted ofmanual polishers and machine operators notexposed to hand transmitted vibration. All thestone workers employed in six districts partic-ipated in the survey (n = 578, 69 8%),whereas in the three other districts they wereselected on the basis of a random sampling ofthe quarries and mills located in the respectivegeographical areas (n = 250, 30.2%). In total,42 quarries and 99 stone mills were surveyed.

MEDICAL INTERVIEWEach stone worker was interviewed by healthand workplace assessment questionnaires sim-ilar to those proposed by Pelmear et al.13 Thequestionnaires were given by occupationalphysicians carefully trained to question thestone workers, employed in the various surveysites, in a standardised fashion. The question-naires contained items on the subject's per-sonal, medical, and work history.Sensorineural (SN), vascular, and musculo-skeletal disorders of the upper extremitieswere investigated. Sensorineural disturbancesin the fingers and hands were staged accord-ing to the following symptom scale, adoptedfrom Brammer et al: stage SNO = no SNsymptoms; stage SNI = intermittent numb-ness with or without tingling; stage SN2 =persistent numbness and reduced sensory per-ception; stage SN3 = persistent numbness,reduced sensory perception, and impairedmanipulative dexterity.14 Vibration inducedwhite finger (VWF) was graded according tothe clinical stages of the Stockholm scale:stage VWF0 = no finger blanching attacks;stage VWF1 = occasional attacks affectingonly the tips of one or more fingers; stageVWF2 = occasional attacks affecting distaland middle (rarely also proximal) phalangesof one or more fingers; stage VWF3 = fre-quent attacks affecting all phalanges of mostfingers.'5 The staging of both neurological andvascular symptoms was made separately foreach hand. The simultaneous presence of thefollowing symptoms and signs was consideredto be suggestive of carpal tunnel syndrome(CTS): (a) paraesthesia, numbness, or painaffecting the median nerve distribution of thehand(s), (b) nocturnal exacerbation of thesensorineural symptoms, (c) Tinel's sign pre-sent, or positive Phalen's test.'6 Further ques-tions concerned history of musculoskeletaldisorders such as persistent pain of the shoul-ders, elbows, wrists, and hands, muscle weak-

ness, and Dupuytren's contracture. Both theworkers exposed to vibration and the controlswere carefully questioned about leisure activi-ties, previous muscle or tendon injuries, bonefractures, constitutional white finger, systemicdiseases (diabetes, connective tissue diseases,cardiovascular, neurological, or joint disor-ders), and regular medical treatment.Cigarette smoking was expressed as pack-years ((cigarettes/day/20) x years smoked).Alcohol consumption was estimated in g/day.

MEASUREMENT AND EVALUATION OFVIBRATION EXPOSUREThe stone workers exposed to vibrationreported a detailed description of the handheld power tools used during their career.Professional usage of vibrating tools wasexpressed in terms of operating h/day, days/y,and total years separately for each tool. Only22 subjects (3 9%) had been engaged in previ-ous jobs with vibrating tools for a short time(0-5-2 y). A workplace tool assessmentshowed that vibrating tools of the same typeand model were used in the quarries andmills, as a very limited number of manufactur-ers supply the Italian stone industry withportable vibratory tools. The tasks performedby the drillers and carvers have beendescribed in detail elsewhere.7 10Hand transmitted vibration was measured

on the handles of a representative sample ofrock breakers (n = 3), rock drills (n = 5),stone hammers (n = 5), and angle grinders (n= 4) used by skilled stone workers underactual operating conditions. Hand held rotaryand percussive tools of varying size and typewere chosen to measure vibration arising fromthe most frequent work operations performedduring stone quarrying and carving. Vibrationacceleration measurements were made in theorthogonal directions X, Y, and Z accordingto the International Standard ISO 5349."7Three accelerometers (Briiel and Kjaer 4374)were firmly attached to an adaptor (Bruel andKjaer UA 0894) tightened around the toolhandle by means of suitable clamps. To avoidzero direct current shifts in the transduceroutput, a butyl rubber sheet (Briiel and KjaerDS 0707) was interposed between the adap-tor and the handle of percussive tools. Beforevibration was measured, the transducers werecalibrated (Briiel and Kjaer 4294), and theaccelerometer connecting cables were care-fully taped to avoid cable movements produc-ing triboelectric noise. The accelerometersignals were amplified by charge amplifiers(Briiel and Kjaer 2635) and recorded on afour channel digital recorder (Teac RD-101T). The acceleration recordings wereanalysed in the laboratory by a real timeanalyser (Larson and Davis 2800). From theone third octave band frequency spectra(6-3-1250 Hz), the magnitude of the rootmean square (rms) of both unweighted accel-eration and frequency weighted accelerationaccording to ISO 5349 was obtained. Thevector sum (ax,.) of the rms unweighted andweighted accelerations was also calculated bythe following formula:

604



.bmj.com

/O

ccup Environ M


eptember 1994. D

ownloaded from

http://oem.bmj.com/

Hand-arm vibration syndrome and dose response relation for vibration induced white finger among quarry drillers and stonecarvers

as= (a.,h2 + aYh2 + aZh2)05 m/s2Daily exposure to vibration was assessed interms of 8 h energy equivalent frequencyweighted acceleration (A(8) in m/s2) accord-ing to the British Standard 6842:A(8) = (T/8) 5- A(T) M/S2where A(T) is the frequency weighted energy

equivalent acceleration for a daily exposure

of Th.'8On the basis of the estimated periods of

tool use, a lifetime vibration dose for eachstone worker was calculated by a method ofsummation suggested by Griffin:Lifetime dose = (E (ahW2 *t)05 td t,)2 m2h3/s4where ahW is the frequency weighted accelera-tion measured on the vibrating tools (m/s2), this the individually estimated daily exposure

(h/day), td is the number of working days/y,and t, is the number of years during which thetool was used.'9

STATISTICAL METHODSData were analysed with the BMDP/Dynamicsoftware (Release 7 0). Continuous data were

summarised as means (SD). The differencebetween two means was tested by Student's ttest and more than two means by one way

analysis of variance (ANOVA). The ScheffEmethod was used for pairwise mean compar-

isons in ANOVA. The relation between con-

tinuous variables was assessed by the methodof the least squares. Appropriate transforma-tions of both the response and the explanatoryvariables used in linear regression analysiswere found by the methods suggested by Boxand Cox20 and Atkinson.21 The x2 statistic wasapplied to data tabulated in 2 x 2 or 2 x k con-

tingency tables. The association betweenupper limb disorders and vibration exposurewas assessed by multivariate logistic regres-sion analysis. Logistic regression coefficientsand standard errors were used to obtainprevalence odds ratios (OR) and 95% confi-dence intervals (95% CI) adjusted for severalpotential confounders. Stepwise selection ofpredictor variables was based on the likeli-hood ratio x2 test. The goodness of fit of the

logistic models was assessed by the Hosmer-Lemeshow x2 statistic.22 To test the hypothesisof a monotonic dose-response relation forvibration induced disorders among theexposed stone workers-that is, increasingrisk with increasing exposure-polynomialregression analysis was performed with qua-

dratic logistic regression as suggested byMaclure and Greenland.23 Incremental oddsratios (IOR), adjusted for covariates, were cal-culated by contrasting the risk for vibrationinduced disorders at each category of expo-

sure with the risk at only the next lower cate-gory. The unexposed category (the controls)was excluded from the quantitative doseresponse analysis.

ResultsTOOL VIBRATIONTable 1 shows the magnitudes of the rms ofthe frequency weighted and unweighted accel-erations measured in the dominant axis ofvibration, and the vector sum of vibrationaccelerations from the power tools used in thequarries and mills. As expected, small differ-ences between the frequency weighted accel-eration in the dominant axis and theacceleration vector sum were found for thepneumatic tools of percussive type such as

rock breakers, rock drills, and stone hammers.During stone drilling and breaking the fre-quency weighted acceleration in the dominantaxis averaged 15 (5-4) M/s2. For the heavyquarry tools, the greatest accelerations were

measured in the percussive direction aroundthe 31 5-Hz band. During stone cutting andcarving with the small stone hammers operat-ing at full throttle, the frequency weightedacceleration in the percussive axis averaged21-8 (6 6) m/s2. Vibration from these toolsshowed the highest accelerations at the funda-mental frequency of 80 Hz and at the har-monics of 160 and 250 Hz. The mean valueof the frequency weighted acceleration mea-

sured on the handles of the rotary tools duringstone grinding and cutting was 2-84 (1 69)

Table 1 Mean magnitude of root mean square (RMS) of the frequency weighted and unweighted acceleration(6 3-1250 Hz) measured in the dominant axis of vibration and the vector sum of vibration accelerations measured on thehandles ofportable vibrating tools during quarrying and stonecarving

Rms acceleration (mls2)

Weighted Unweighted

Tool type Weight (kg) Dominant axis Vector sum Dominant axis Vector sum

Rock breaker:A 9 10-5 14-3 87-7 100-2B 27 9 55 10-2 77-5 89-1C 24 9-89 13-6 83-6 97-6

Rock drill:A 16 18 6 19-8 83-0 111-7B 21 20-9 21-6 114-8 132-1C 27 19-3 20-2 87-6 110-7D 12 12-4 14-7 71-9 93-6E 18 18-2 19-4 83-3 96-3

Stone hammer:A 1 21-2 22-6 120-2 140-8B 1-25 25-1 26-2 131-1 148-2C 0-5 13-0 13-2 89-2 94-3D 1-1 19-7 21-1 98-8 128-4E 1.9 29-9 32-1 138-6 156-7

Angle grinder:A 5-5 2-85 4-56 49 5 75-4B 1-5 1-09 1-71 25-1 36-9C 4-5 4-92 5-05 33-6 38-0D 4-8 1-73 2-26 28-8 42-9

605



.bmj.com

/O

ccup Environ M


eptember 1994. D

ownloaded from

http://oem.bmj.com/


Table 2 Characteristics of the controls and the stoneworkers exposed to hand transmitted vibration

Controls Stone workers(n = 258) (n = 570)(n (%)) (n (%))

Age (y):<30 89 (34-5) 196 (34-4)30-45 99 (38 4) 148 (26 0)>45 70 (27-1) 226 (39.6)*

Cigarette smoking (pack-y):0 169 (65 5) 329 (57-7)<10 40 (15-5) 108 (18-9)>10 49 (19.0) 133 (23-3)

Alcohol (glday):0 77 (29 8) 161 (28 2)<50 102 (39 5) 254 (44 6)>50 79 (30 6) 155 (27 2)

Cardiovascular drugs 7 (2 7) 27 (4 7)Upper limb injuries 62 (24 0) 161 (28 2)Previous jobs with

vibrating tools 0 (0) 22 ( 3 9)

*p < 0 001 byx2 test.

m/s2. The greatest vibrations occurred at 100Hz (fundamental frequency) and at 200 and400 Hz.

CHARACTERISTICS OF THE WORKER GROUPSThe vibration exposed stone workers were, on

average, older than the controls (39 1 v 36&7y, P < 0-01). Between the two groups no dif-ference in other individual characteristics wasfound (table 2). Seven workers exposed tovibration (1-2%) and three controls (1-1%)had a positive family history for Raynaud likesymptoms, but these subjects had no vasculardisturbances at the time of the survey. Onestone worker was affected with a mild formof asymptomatic non-insulin dependent dia-betes. No subjects had disorders of the con-nective tissues. Medical treatment forcardiovascular diseases (hypertension,ischaemic, or valvar heart diseases) wasreported by seven controls (2-7%) and 27stone workers exposed to vibrations (4-7%,P = 0-19). Univariate analysis showed noassociation between systemic diseases andvibration exposure. According to these find-ings, systemic diseases were not considered tobe important confounders and, as a. result, nosubjects were excluded from the study.Among the stone workers who used hand

held power tools, vibration exposure in termsof years of tool usage, A(8), and lifetime dosewas found to be greater in the quarry drillersand stonecarvers B than in the stonecarvers A

Table 3 Mean (SD) exposures to hand transmitted vibration in the quarry drillers, andthe stonecarvers who use only rotary tools (A) or both rotary and percussive tools (B)

Quarry Stonecarvers Stonecarversdrillers A B Total(n = 145) (n = 188) (n = 237) (n = 570)

Age (y) 40 3 37-9 39 4 39-1(12-2) (11-8) (13-7) (12.7)

Duration of 18-3 14-9 18-9* 17-4exposure (y) (13-2) (10-6) (13.6) (12-7)Daily exposure 4-1 4.3 4.9 4.5(h) (08) (1-7) (09) (1-2)Yearly exposure 940 978 1112** 1024(h/y) (397) (534) (466) (479)A(8)t (m/s') 12-4 2-14 10-8** 8-37

(3-3) (2-0) (4-7) (5-7)Lifetime vibrations 22-9 18 7 22.6** 21-4(In (m2h3/S4)) (2.1) (2 4) (2 4) (3'0)

F test: *p < 0-01; **p < 0-001.tA(8) is the frequency weighted energy equivalent acceleration for a period of 8 h.:Lifetime vibration is expressed on a logarithmic (In) scale.

Table 4 Distribution of upper limb disorders among thecontrols and the stone workers exposed to hand transmittedvibration: the ORs were adjustedfor several covariates(age, smoking, alcohol consumption, and upper limbinjuries) by logistic modelling

Controls Stone workers(n = 258) (n = 570)

Disorders (n (%)) (n (%)) OR (95% CI)

Sensorineural 42 (16-3) 228 (40 0) 3 49 (2-36-5 15)disturbancesSymptoms ofVWF 11 (4 3) 172 (30 2) 9 33 (4-91-17-8)Signs and symptoms 6 (2 3) 50 (8 8) 3-43 (1-42-8-28)of CTSDupuytren's 9 (3 5) 57 (10 0) 2-60 (1-24-5-49)contractureMuscular 2 (0 8) 39 (6 8) 7-78 (1 84-32-9)weaknessPain in the 45 (17 4) 194 (34 0) 2 27 (1 55-3-33)upper limbs

VWF = vibration induced white finger; CTS = carpal tunnelsyndrome.

(table 3). In the entire vibration group, themean value of daily exposure time was 4-5h/day, A(8) was 8&4 m/s2, and total duration ofexposure was 17 4 y. The length of employ-ment in the stone industry averaged 15-5 y inthe control group (P > 0 1).

DISORDERS OF HAND-ARM VIBRATIONSYNDROMEAfter adjustment for potential confounders(age, smoking, alcohol consumption, andupper limb injuries), the prevalence oddsratios for the workers exposed to vibrationcompared with the controls significantlyexceeded unity for all the upper limb disor-ders investigated (table 4). In the vibrationgroup the observed prevalences were 40 0%for SN disturbances (OR = 3-49), 30-2% forVWF (OR = 9 33), 8-8% for signs and symp-toms of CTS (OR= 3-43), and 10-0% forDupuytren's contracture (OR = 2 60). Thestone workers exposed to vibration also com-plained more frequently ofmuscular weaknessand pain in the upper limbs. Significantlyincreased ORs for most disorders were also

Table 5 Distribution of upper limb disorders among thequarry driers, and the stonecarwers who use only rotarytools (A) or both rotary and percussive tools (B)

Quany Stonecarvers Stonecarversdrivers A B

Disorders (n = 145) (n = 188) (n = 237)

Sensorineural disturbances:No(%) 58 (400) 77 (41-0) 93 (39-2)OR 3-14 3-98 3-3695% CI 192-5 14 2-49-634 2 145-27

Symptoms ofVWF:No (%) 59 (40 7) 26 (13-8) 87 (36-7)OR 15.1 3 43 12 895% CI 7-41-30 7 1-62-7-25 6-50-1725

Signs and symptoms of CTS:No (%) 21 (14-5) 14 (7 4) 15 (6 3)OR 5.59 3-24 2-2795% CI 2-1414-6 1-208-77 0-84-612

Dupuytren's contracture:No (%) 16 (11-0) 12 (6 4) 29 (12-2)OR 2-58 1-85 3-2395% CI 1-07-6-20 0-744-61 1-447-23

Muscular weakness:No (%) 15 (10-3) 6 (3 2) 18 (7-6)OR 11-5 3-91 8-6895% CI 2-53-51-8 0-77-19-8 1-96-38-5

Pain in the upper limbs:No (%) 47 (32 4) 62 (33-0) 85 (35 9)OR 1-96 2-37 2-4095% CI 1-18-3-23 1-49-3-77 1-54-3-74

Adjustments and abbreviations as for table 4. The controlswere assumed to have OR = 1-0.

606



.bmj.com

/O

ccup Environ M


eptember 1994. D

ownloaded from

http://oem.bmj.com/


Table 6 Distibution of sensoineural (SN) symptoms and vibration induced white finger (VWF) by stages in thecontrols, quarry drillers, and stonecarvers who use only rotary tools (A) or both rotary and percussive tools (B)

Stone workers

Controls Quany drillers Stonecarvers A Stonecarvers B Total(n = 258) (n = 145) (n = 188) (n = 237) (n = 570)

Symptom stages (n (%o)) (n (%o)) (n (%)) (n (Co)) (n (%o))

SN stages:SNO 216 (83 7) 87 (60 0) 111 (59-0) 144 (60 8) 342 (60 0)SNI 33 (12 8) 31 (21 4) 58 (30 9) 52 (21-9) 141 (24 7)SN2 4 (1-6) 10 (6 9) 10 (5 3) 19 (8-0) 39 (68)SN3 5 (1 9) 17 (11-7) 9 (4 8) 22 (9-3) 48 (8 4)

VWF stages:VWFO 247 (95 7) 86 (59-3) 162 (86-2) 150 (63 3) 398 (69 8)V1WF1 8 (3-1) 13 (9 0) 10 (5 3) 12 (5-1) 35 (6 1)VWF2 2 (0 8) 27 (18 6) 9 (4-8) 32 (13 5) 68 (11 9)VWF3 1 (0 4) 19 (131) 7 (3 7) 43 (18 1) 69 (12 1)

found for each of the job categories exposedto vibration compared with the controls (table5). The prevalence of VWF was found to begreater among the quarry drillers (40 7%) andthe stonecarvers B (36-7%) than among thestonecarvers A (13-8%). With the stone-carvers A as the reference category, theadjusted OR for VWF was 4 40 (95% CI =2 50-774) for the quarry drillers and 3-75(95% CI = 2-22-6&33) for the stonecarvers B.No significant difference in the occurrence ofother disorders was found between the jobcategories exposed to vibration. The distribu-tion of SN disturbances by stage was similaramong the workers exposed to vibration (table6), whereas moderate or severe symptoms of

Table 7 Distribution ofupper limb disorders in the vibration exposed stone workers,divided into categories oflifetime vibration dose (In scale)

Lifetime vibration dose (In (m2h3/s'))

<19 5 19 5-21-5 21 5-24 >24Disorders (n = 145) (n = 157) (n = 131) (n = 137)

Sensorineural disturbances:No (%) 38 (26-2) 56 (35-78) 50 (38 2) 84 (61-3)OR 2-91 3-29 3-12 46995% CI 1-704-97 2-02-5-36 1-89-5-17 2-81-7-82

Symptoms ofVWF:No (%) 14 (9 7) 25 (15-9) 46 (35-1) 87 (63-5)OR 2-70 4-29 11-3 27-395% CI 1-17-6-26 2-03-9-08 5-56-23-1 13 1-56-6

Signs and symptoms of CTS:No (%) 4 (2-8) 11 (7 0) 16 (12-2) 19 (13-9)OR 1-85 326 5-11 32495% CI 0-50-6-91 1-16-9-19 1 91-137 1-21-8-69

Dupuytren's contracture:No (%) 6 (4-1) 11 (7 0) 13 (9 9) 27 (19 7)OR 1-93 2-25 2 57 3 2095% CI 0-64-584 0-88-5-72 1-04-6-36 1-39-7-37

Muscular weakness:No (%) 5 (3 4) 2 (1-3) 9 (6 9) 23 (16-8)OR 6 13 1-60 8-33 14-795% CI 1-14-33-0 0-22-11-6 1-75-39-6 3-25-66-6

Pain in the upper limbs:No (%) 30 (20 7) 47 (29-9) 41 (31-3) 76 (55 5)OR 1-75 2-19 2-02 3 1595% CI 1-01-3-02 1-34-3-56 1 21-3-37 1-91-5 20

Adjustments and abbreviations as for table 5.

Table 8 Dose-response relation for vibration induced white finger among the stoneworkers, divided into categories of lifetime vibration dose (an scale): incremental odds ratios(IOR) were obtained by polynomial regression, contrasting the risk at each category ofexposure with the risk of the next lower category

Lifetime vibration dose (In (m2h3/s4))<195 195-21-5 21 5-24 >24(n = 145) (n = 157) (n = 131) (n = 137)

OR (95% CI) 1-0 1 60 (0 78-3-28) 4-23 (2-14-8&37) 10-2 (4-81-21-6)IOR (95% CI) 1-93 (1-07-3-45) 2-10 (1-42-3-10) 2-83 (1-854-34)

Adjustments and abbreviations as for table 4. The lowest exposure category was assumed tohave OR= 1-0.

VWF (stages 2 and 3) were more frequentlyfound in the quarry drillers and stonecarversB than in the stonecarvers A (P < 0-001).Most of the workers who had VWF experi-enced blanching attacks in both hands(70 3%). The second, third, and fourth fin-gers were the most affected ones (18-8%-23 0%). No significant association was foundbetween SN disturbances, signs and symp-toms of CTS, and VWF (P > 0 35), suggest-ing that the various components of thehand-arm vibration syndrome may developindependently of each other.'4 15

RELATION BETWEEN UPPER LIMB DISORDERSAND VIBRATION EXPOSUREThe occurrence of sensorineural, vascular,and musculoskeletal disorders was also investi-gated by vibration exposure. Table 7 showsthe adjusted ORs for the stone workersexposed to vibration divided into several cate-gories of lifetime dose, when compared withthe controls. Significant associations betweenupper limb disorders and vibration exposurewere found, mainly for the stone workers witha cumulative vibration dose >215 m2h'/s4 (lnscale). Within the vibration group, however,only VWF showed a pattern of increasingORs with increasing vibration exposure (table8). All of the lower 95% CIs for the incremen-tal OR estimates were >1, providing evidencefor an increasing dose-response relationbetween VWF and vibration exposure. Itshould be noted that the lowest dose categoryconsisted primarily of stonecarvers who oper-ated only rotary tools generating low magni-tudes of hand transmitted vibration. In theexposure-response analysis, we found a con-tinuously increasing risk for VWF withincreasing equivalent daily acceleration andduration of tool usage (results not shown).The log odds of risk of VWF associated

with vibration exposure was also estimatedwith A(8) and duration of exposure as quanti-tative predictor variables (fig 1). The logisticmodel including linear terms for each of A(8)and duration of exposure achieved an excel-lent goodness of fit (Hosmer-Lemeshow x2 =

2-295, degrees of freedom = 8, P = 0-97 1).The specific test for curvature in the regres-sion line was not significant (P = 0343 for thequadratic effect of A(8) and P = 0-149 for thequadratic effect of duration of exposure). Nointeraction of A(8) with duration of exposure

607



.bmj.com

/O

ccup Environ M


eptember 1994. D

ownloaded from

http://oem.bmj.com/


3

2

1-

+

0U,

00)0-j

0 5 10 15 20 25 30

Duration of exposure (y)

Figure 1 Log odds of occurrence of vibration inducedwhite finger (VWF) according to 8 h frequency weightedenergy equivalent acceleration (A (8), x, in mis2) andduration of vibration exposure (x, in y), included in thelogistic model as quantitative independent variables. Ongrounds of expediency, 3 has been added to each of the logodds in the graph.In (P1(l-P)) = -2954 + 0-09923 (xl) + 0-06302 (x2)Goodness offit x2 (Hosmer-Lemeshow) = 2-295, df = 8,P = 0 971

was found. Hence, the results of the quantita-tive logistic analysis suggested that the effectsof A(8) and duration of exposure combined toincrease the risk for VWF among the stoneworkers exposed to vibration. In particular,the OR for VWF was estimated to increase by1-10 (95% CI = 106-1-15) for each unit ofdaily vibration exposure (m/s2) and by 1 07(95% CI = 1-05-1-08) for every unit of expo-sure duration (y). It is also remarkable thatthe baseline probability of white fingerpredicted by the logistic model was 0 049, afigure very similar to that found among thecontrols (4 3%).

RISK ASSESSMENT FOR VWF AMONG THESTONEWORKERSFor purposes of comparison with the doseeffect guidances included in the annexes tosome Standards,'718 the observed prevalenceof VWF was related to the midpoints of sev-eral intervals of A(8) and duration of expo-sure. Tests for data transformations suggesteda linear model in which the ln transformedprevalence of VWF was regressed on In A(8)and in duration of exposure (adjusted R2 =0-908, fig 2 and table 9). According to theexposure data of this study, the estimatedregression equation indicates that theexpected percentage of stone workers affectedwith VWF tends to increase roughly in pro-portion to the square root of A(8) (for a par-

Table 9 Expected prevalence of vibration induced whitefinger (%) among the stoneworkers according to the estimated 8 h frequency weighted energy equivalent acceleration(A (8) in mis') and the duration ofexposure: (figure 2 shows the estimated regressionequation)

Duration ofexposure (y)

A(8) (mYs2) 1 2-5 5 10 15 20 30

1 2-8 4-4 6-2 8-8 10-8 12-5 15-32-5 4-4 7-0 9-9 14-0 17-1 19-7 24-25 6-2 9-9 14-0 19-7 24-2 27-9 34-2

10 8-8 14-0 19-7 27-9 34-2 39-5 48-315 10-8 17-1 24-2 34-2 41-9 48-3 59-2

100A(8) 15 rn/s2A(8) 10 rn/s2

/ /.- A(8) 5 r/s2o A(8) 2.5 M/s2o S 9 _ , A(S) 1 rn/s2

CL

L- 1 10 100

Duration of exposure (y)Figure 2 Expected occurrence of vibration induced whitefinger (FIEF) among the stone workers operatingvibrating tools, as estimated by regression of the log (In)transformed VZF prevalence (y) on logA (8)(8 h frequency weighted energy equivalent acceleration, x,in mls2) and log duration of vibration exposure (x2 in y):1ny = 1 0266 + 0 4747 (In xd + 0-535 (In x2)The regression equation was approximated to:y = 2 79156 * W1) * (x2).

ticular exposure period) or in proportion tothe square root of the duration of exposure(for a vibration of constant magnitude). Thisrelation was confirmed by that found betweenVWF and lifetime vibration dose (fig 3). Ongrouping the stone workers into increasingintervals of cumulative dose, the expectedoccurrence of VWF was found to be propor-tional to a power of the lifetime dose (dosedadjusted R2 = 0-971).

DiscussionVALIDITY OF THE STUDY AND COMPARISONWITH OTHER INVESTIGATIONSIn this study of stone workers exposed to handtransmitted vibration, the overall prevalenceof VWF was found to be 30% and sensori-neural symptoms 40%. These figures arequite similar to those reported by most of theauthors who investigated the occurrence ofvibration induced disorders in the stoneindustry (table 10). The very high prevalence

0a)

0

a)5)a-

0-

y = 6-327 x0-24981

10 100 1000 10 000 100 000

Lifetime vibration dose ((M2 h3/s4)/107)

Figure 3 Relation between the prevalence of vibrationinduced white finger (VWF) and the estimated lifetimevibration dose in the stone workers who use vibrating tools.

608

I0



.bmj.com

/O

ccup Environ M


eptember 1994. D

ownloaded from

http://oem.bmj.com/


Table 10 Observed prevalence of vibration induced whitefinger (VWF) and sensorineural (SN) symptoms inreports ofepidemiological studies ofstone workers exposedto hand transmitted vibration

VWF SN symptomsSample

Author(s) (n (N(%)) (N1/o))Longs' (1911) -200 - 40 (20 0)Edsall* (1918) 19 19 (100) -Hamilton2 (1918) 38 34 (89-5) -

50 43 (86-0) -78 44 (564) -

Takamatsu (1973)** 58 24 (42-0) 38 (66-0)Osaki (1974)** 61 21 (344) 12 (19-7)Iwata (1975)** 90 40 (44-4) -Miura3 (1975) 70 26 (37-1) 24 (34 3)Miura (1976)** 71 28 (39-4) 28 (40-1)Nakaya (1978)** 314 64 (20-1) -Firkkilf et al (1978) 16 14 (87-5) -Olsen and Nielsen5 (1979) 18 13 (72-0) -Kuzalovi et al* (1984) 174 90 (52-0) -Taylor et all (1984) 30 19 (63-3) 11 (30-0)Sakakibara et aP (1984) 69 25 (36 2) -Futatsuka et aP (1985) 42 13 (31-0) 23 (54-8)Bovenzi et al °(1988) 76 27 (35-5) 31 (40 8)Tominaga'2 (1992) 69 20 (29 0) 25 (36 2)Present study (1993) 570 172 (30 2) 228 (40-0)

*Cited by Griffin".**Cited by Takamatsu et al.6

ofVWF found in the studies performed from1910-1920 (56%-100%) is probably due toan excessive daily tool use (from 7-10 h/dayaccording to Lorigal and Hamilton2).Discrepancies with the results of other surveys

may also depend on differences in the studydesign and the sample sizes, which in generalwere much smaller than that of our study. It iswell known that prevalence studies are suit-able for investigating occupational diseasespersisting for long periods of time, but theycan have various limitations. On planning thisstudy several efforts were made to controlpotential sources of bias. From the registers ofthe companies it seemed that by 1975 thelevel of employment was stable in the quarriesand mills investigated in this study. Thisinformation, however, cannot exclude selec-tion bias due to work force turnover, as onlyactively employed workers were investigated.Nevertheless, according to employers'appraisal there was little job mobility in thelast 15 years, during which time stone produc-tion in Italy increased more than 10%.Likewise, changes in job categories within theindustry were negligible, as stone processingrequires skilled labour. Furthermore, the find-ing of an increasing occurrence of upper limbdisorders with increasing age for both theworkers exposed to vibration and the controls(test for linear trend: P < 0-001), as well as

the use of an internal comparison group withsimilar socioeconomic characteristics, suggest

that bias due to the healthy worker effect was,at least partially, minimised. All the activestone workers participated in the survey, so

that self selection was not a source of bias inthis study. Data on current exposure to vibra-tion was considered a reliable surrogate forpast exposure as the type and design of mostvibrating tools had remained fairly similarover time.710 In this investigation, subjects'daily exposure time and total years of tool use

were estimated on the basis of informationobtained by interviewing employees andemployers and by consulting personnel

employment records, when available.Certainly, daily and lifetime exposures may besubject to recall bias. Nevertheless, there issome evidence for a good concordancebetween estimated and measured exposuretime among workers exposed to vibration.24 Inthis study the occurrence of vibration induceddisorders was investigated by assessmentquestionnaires and the Stockholm workshopscales were used to grade sensorineural andvascular symptoms. We recognise that symp-toms reported by patients may be open tobias. Nevertheless, in view of the large popu-lation studied the use of assessment question-naires, based on international symptom scalesand given by trained occupational physicians,may be considered appropriate to investigatethe occurrence of vibration induced disordersamong worker groups at risk.

NON-VASCULAR DISORDERSThe findings of our study showed that theprevalence of upper limb disorders was signif-icantly greater among the stone workersexposed to vibration than among the controlswho performed only manual work. Theoccurrence of sensorineural disturbancestended to increase with increasing exposure tovibration, but a linear dose-response relationcould not be shown. It may be argued that thesensorineural scale adopted in this study is notfully adequate to discover an effect of expo-sure and this limitation may be responsible forthe lack of significant findings. For other dis-orders including CTS, Dupuytren's contrac-ture, muscle weakness, and pain in the upperextremities, trend statistics did not show anincreasing risk with increasing lifetime dose ofvibration. It is likely that as well as vibration,several other stress factors can contribute tothe onset and development of musculoskeletaldisorders. Working with vibrating tools duringquarrying and stone processing involves notonly vibration exposure, but also awkwardpostures, firm hand grip on tool handles,forceful and sometimes repetitive movementswhich can overload the muscles, tendons, andbones of the upper limbs. From a medicolegalpoint of view, it is worth noting that a recentrecommendation of the Commission of theEuropean Communities (EC) includes thedisorders due to overstraining of the tendonsheaths, the peritendinous tissues, and themuscular and tendinous insertions, in a list ofdiseases recognised to be linked directly to theoccupation.25 According to the ECCommission, the Member States should con-sider these occupational diseases liable forcompensation and subject to preventive mea-sures.

DOSE-RESPONSE RELATION FOR VWFThe association between VWF and occupa-tional exposure to hand transmitted vibrationis well recognised, but the form of the expo-sure-response relationship for VWF is not yetfully understood.1126 In this study, symptomsof VWF were found to be associated withseveral indicators of exposure to vibrationsuch as equivalent daily acceleration, total

609



.bmj.com

/O

ccup Environ M


eptember 1994. D

ownloaded from

http://oem.bmj.com/

Bovenzi and the Study Group on Physical Hazards in the Stone Industry

exposure duration, and lifetime dose.Furthermore, within the group exposed tovibration there was evidence that the risk forVWF continued to increase with each incre-ment of vibration exposure, suggesting amonotonic dose-response relation.Annex A to ISO 534917 proposes a dose-

effect relation between the energy equivalentfrequency weighted acceleration for a periodof four hours-that is, A(4) = A(8)]V/2-andthe duration of exposure necessary before theonset of VWF-that is, the latency for fingerblanching. On the basis of the observed VWFprevalence and the estimated A(4) for thestone workers of this study, the ISO equationpredicted latent periods of 3-44 years for thequarry drillers, 11 -6 years for the stonecarversA, and 3-76 years for the stonecarvers B. Theobserved mean latencies for VWF were 16-5years for quarry drillers, 12-7 years for stone-carvers A, and 16 1 years for stonecarvers B.These findings indicate a good agreementbetween the expected and observed latenciesfor the stonecarvers operating only rotarytools, and an overestimation of risk of VWFfor the stone workers exposed to vibrationfrom percussive tools. The tendency of ISO5349 to overestimate the risk in some cate-gories of workers exposed to vibration hasbeen reported by several investigators.'027-29 Itmay be argued that the dose-effect guidanceoffered by ISO 5349 estimates correctly therisk for worker groups exposed to vibrationfrom specific types of tools-for example,grinders, chain saws-whereas it is not applic-able to all other sources of hand transmittedvibration. For instance, it has been suggestedthat the ISO frequency weighting factors maybe inappropriate for hand held tools generat-ing vibrations with dominant low frequencies.A substantial difference between the dose-

effect relation suggested by ISO 5349 and thatestimated in the present survey arises from thedefinition of exposure duration. In the stan-dard the mean duration of exposure repre-sents the mean latent period required beforeVWF symptoms develop in selected per-centiles of a group exposed to vibration. But,as discussed by Griffin, within a populationgroup the mean latency for the individualsaffected with VWF is always shorter than themean vibration exposure period for the groupmembers, and this leads to overestimate therisk for VWF with respect to the vibrationexposure (magnitude and duration) experi-enced by the entire worker group." In ourstudy, the dose-response relation for VWFamong the stone workers exposed to vibrationcould be approximated by a relation in which a

twofold change in the percentage of workersaffected results from a fourfold change in A(8)(for the same number of years of exposure) orfrom a fourfold change in exposure duration(for a constant magnitude of equivalent dailyvibration). In contrast, the ISO dose-effectrelation predicts a fourfold increase in occur-rence of VWF for a twofold increase in fourhours energy equivalent acceleration (with thelatent period unchanged). As suggested bysome investigators, dose-response relations

based on the mean latency as an indicator ofexposure duration tend to allow greater preva-lences of VWF with lower vibration magni-tudes.1 26 Hence, it is not surprising that theuse of different quantities to express exposureduration (latency or total exposure period)can result in discrepancies between studies inthe risk estimates for VWF.

It is recognised that the prevalence ofsymptoms of VWF in a group exposed tovibration depends on several factors includingthe characteristics of vibration exposure (mag-nitude, frequency, duration), the operator'smethod of working, the environmental condi-tions, and the individual susceptibility.Prevalence, as an effect measure, is also highlydependent on the rate at which workers enterand leave the group. Even though the relationof VWF to vibration exposure has proved tobe complex and the results of cross sectionalsurveys should be interpreted with caution,nevertheless the findings of this study suggest asimple dose-response relation based on a timedependency such that, if vibration magnitudesare doubled, a halving of the years of exposureis required to produce the same effect. Thus,within the frame of the currently proposedtime dependencies for vibration exposure, thisstudy tends to substantiate a form of dose-response relation in which vibration magni-tude and total duration of exposure contributeequally to the prediction of occurrence ofVWF. This finding provides epidemiologicalsupport to some general statements containedin hand transmitted vibration standards718and adds further dose-effect information forfuture development of the current standards.Even though limited to a specific category ofworkers exposed to vibration our results mayalso be used to assist in the formulation ofexposure limits. With regard to this subject,the EC Commission has recently suggestedexposure levels for hand transmitted vibrationwithin a proposal of directive for the protec-tion of workers from the risks arising fromphysical agents.30 In the proposal of directivethe methods of measurement and assessmentof vibration exposure are basically derivedfrom BS 6842,18 and the exposure levels areexpressed in terms of A(8). The thresholdlevel is established at 1 m/s2, the action level at2-5 m/s2, and the ceiling level at 5 m/s2.Specific provisions are indicated for exposurevalues above the threshold level, which isdefined as "the value towards which imple-mentation of this Directive should be geared".Considering a prevalence of 10% as a thresh-old effect value for VWF in a group exposedto vibrations the dose-response relation of thisstudy predicts that such a prevalence willoccur after about 5-1 years of exposure to theEC action level. This figure is similar to thatsuggested in a recent review paper,3' and is notfar from the estimates provided by BS 6842.18

ConclusionThe findings of this study showed a greateroccurrence of upper limb disorders in quarrydrillers and stonecarvers exposed to vibration

610



.bmj.com

/O

ccup Environ M


eptember 1994. D

ownloaded from

http://oem.bmj.com/


than in control stone workers performing onlymanual activity. As well as vibration,ergonomic stress factors are likely to haveplayed a part in the development of carpaltunnel syndrome and musculoskeletal disor-ders among the stone workers who use handheld vibrating tools. Symptoms ofVWF werestrongly related to vibration exposure, and amonotonic dose-response relation could beshown. Even though the results of this studyconcern the health hazards associated with theuse of vibratory tools in a specific work situa-tion, nevertheless the estimated relationbetween VWF and exposure to vibration wasfound to be consistent with the current stateof knowledge of the dose-effect relation forhand transmitted vibration.'7 Differences inthe estimates of the expected occurrence ofVWF between different studies are probablydue to several factors such as the variability indose-response data that arise from differentjobs and exposure conditions, the use of non-uniform methods for the assessment of dailyand cumulative exposure to vibration, andsome general limitations related to the designof occupational cross sectional studies. Ourfindings and the results of other epidemiologi-cal studies seem to indicate that the vibrationacceleration levels currently under discussionwithin the EC represent reasonable exposurelimits for the protection of workers against theharmful effects of hand transmitted vibra-tion.32 The adoption of the proposed vibrationlimits, together with the implementation ofthe administrative, technical, and medicalmeasures specified in the EC directive forphysical agents,30 should contribute todecrease the risk of disorders induced byvibration among the exposed workers.

1 Loriga G. II lavoro con i martelli pneumatici. Bollettino delIspettorato del Lavoro 191 1;2:35-60.

2 Hamilton A. A study of spastic anemia in the hands ofstonecutters. In: Bull US Bureau of Labor Statistics, No236. Industrial accidents and hygiene. Washington, DC:Government Printing Office, 1918:53-66 Series No191.

3 Miura T. On the vibration syndrome in Japan due tohandheld vibration tools. Journal of Science of Labour1975;31:771-87.

4 Farkilla M, Starck J, Hyvarinen J, Kurppa K. Vasospasticsymptoms caused by asymmetrical vibration exposure ofthe upper extremities to a pneumatic hammer. Scand JWork Environ Health 1978;4:330-5.

5 Olsen N, Nielsen SL. Diagnosis of Raynaud's phenome-non in quarrymen's traumatic vasospastic disease. ScandJ Work Environ Health 1979;5:249-56.

6 Takamatsu M, Futatsuka M, Sakurai T, Matoba T, GotohM, Aoyama H, et al. A study of the extent and scope oflocal vibration hazards in Japan. Ind Health 1982;20:177-90.

7 Taylor W, Wasserman D, Behrens V, Reynolds D,Samueloff S. Effect of the air hammer on the hands ofstonecutters. The limestone quarries of Bedford,Indiana, revisited. BrJ Ind Med 1984;41:289-95.

8 Sakakibara H, Miyao M, Nakagawa T, Yamada S5Kobayashi F, Ono Y, et al. Vibration hazards in quarryworkers. Japanese Journal of Industrial Health 1984;26:

170-6. (In Japanese).9 Futatsuka M, Yasutake N, Sakurai T, Matsumoto T.

Comparative study of vibration disease among operatorsof vibrating tools by factor analysis. Br J Ind Med1985;42:260-6.

10 Bovenzi M, Franzinelli A, Strambi F. Prevalence of vibra-tion-induced white finger and assessment of vibrationexposure among travertine workers in Italy. Int ArchOccup Environ Health 1988;61:25-34.

11 Griffin MJ. Handbook of human vibration. London:Academic Press, 1990.

12 Tominaga Y. Age at commencement of vibrating toolusage and the resulting onset of VWF. In: Proceedingsof the 6th international conference on hand-armvibration. Bonn; Hauptuerbrand-der-Gewerblichen-Berufsgenossenschaften 1992:919-23.

13 Pelmear PL, Taylor W, Wasserman DE, eds. Hand-armvibration-a comprehensive guide for occupational healthprofessionals. New York: Van Nostrand Reinhold, 1992:201-14.

14 Brammer AJ, Taylor W, Lundborg G. Sensorineural stagesof the hand-arm vibration syndrome. Scand J WorkEnviron Health 1987;13:279-83.

15 Gemne G, Pyykk6 I, Taylor W, Pelmear PL TheStockholm workshop scale for the classification of cold-induced Raynaud's phenomenon in the hand-arm vibra-tion syndrome (revision of the Taylor-Pelmear scale).ScandJ Work Environ Health 1987;13:275-8.

16 Anonymous. Occupational disease surveillance: carpaltunnel syndrome. MMWR Morb Mortal Waty Rep.1989;38:485-9.

17 International Organization for Standardization. Mechanicalvibraion-guidelines for the measurement and the assessmentof human exposure to hand-transmited vibration. Geneva:ISO, 1986:5349.

18 British Standards Institution. Measurement and evaluationof human exposure to vibration transmitted to the hand.London: BIS, 1987:6842.

19 Griffin MJ. The effects of vibration on health.Southampton: University of Southampton, ISVRMemorandum, 1982:632.

20 Box GEP, Cox DR An analysis of transformations (withdiscussion). J R Stat Soc 1964;26:211-46.

21 Atkinson AC. Plots, transformations and regression. Oxford:Oxford Sci Publ, 1985. (Oxford Statistical ScienceSeries 6.)

22 Hosmer DW, Lemeshow S. Applied logistic regression. NewYork: John Wiley, 1989.

23 Maclure M, Greenland S. Tests for trend and doseresponse: misinterpretations and alternatives. Am 3Epidemiol 1992;135:96-104.

24 Nilsson T, Burstr6m IL, Hagberg M. Risk assessment ofvibration exposure and white fingers among platers. IntArch Occup Environ Health 1989;61:473-81.

25 Commission of the European Communities. Commissionrecommendation of 22 May 1990 to the Member States con-cerning the adoption of a European schedule of occupationaldiseases. Brussels: Official Journal of the EuropeanCommunities, 1990. (90/326/EEC, No L 160/39-48,26-6 90.)

26 Gene G, Lundstr6m R, Hansson JE. Disorders induced bywork with hand-held vibrating tools. Solna: Arbeten OchHilsa, 1993:6.

27 Futatsuka M, Sakurai T, Ariizumi M. Preliminary evalua-tion of dose-effect relationship for vibration-inducedwhite finger in Japan. Int Arch Occup Environ Health1984;54:201-21.

28 Pelmear PL, Leong D. Hand-arm vibration syndrome infoundrymen and miners in Ontario. In: Abstracts of the4th international symposium on hand-anm vibration.Helsinki: Institute of Occupational Health 1985:78.

29 Tasker EG. Assessment of vibration levels associated withhand-held roadbreakers. Scand J Work Environ Health1986;12:407-12.

30 Council of the European Communities. Proposalfora coun-cil directive on the minimum health and safety requirementsregarding the exposure of workers to the risks arising fromphysical agents. Brussels: Official Journal of the EuropeanCommunities, 1993. (93/C77/02, No C 77/12-29,18-3-93.)

31 Brammer AJ. Thresholds for exposure of the hands tovibration. In: Proceedings ofthe 6th international conferenceon hand-arm vibration. Bonn: Hauptuerbrand-der-Gewerblichen-Berufsgenossenschaften 1992:61-9.

32 Inaba R, Mirbod SM, Komura Y, Yoshida H, Nagata C,Miyashita K, et al. A vibration-dose limit forJapanese workers exposed to hand-arm vibration. In:Proceedings of the 6th international conference on hand-armvibration. Bonn: Hauptuerbrand-der-Gewerblichen-Berufsgenossensehaften 1992:913-8.

611



.bmj.com

/O

ccup Environ M


eptember 1994. D

ownloaded from

http://oem.bmj.com/

Documents

Hand-armvibration syndromeThe term hand-arm vibration syndrome is used to refer to the collection ofperipheralneurological, vascular, and musculoskeletal symptoms that are recognised