Volume 22, No. 3/4
2001

[Table of Contents]

Assessment of Hand-Arm Vibration Syndrome in a Northern Ontario Base Metal Mine

Colleen E Hill, Wendy J Langis, John E Petherick, Donna M Campbell, Ted Haines, Joel Andersen, Kevin K Conley, Jason White, Nancy E Lightfoot and Randy J Bissett

Abstract

The objectives of this study were to determine the prevalence of hand-arm vibration syndrome (HAVS) in 617 workers at a base metal mine in northern Ontario and to educate, advise, and make recommendations on the prevention of HAVS. Workers who were employed at the mine between 1989 and 1994 and who continued to live within a 100 km radius of the mine were sent a self-reported questionnaire to identify individuals with possible vibration-induced symptoms in their upper extremities. Of the 162 workers who attended a medical examination, 50% were diagnosed with HAVS and 26% had other diagnoses, some having multiple afflictions e.g., both HAVS and carpal tunnel syndrome (CTS). No vibration-induced symptoms were reported in the 35% of workers who were clinically normal. Ongoing commitments to technological improvements, mandatory and regular rest periods, and continuing educational sessions on the syndrome should help to reduce the prevalence of this disease.

Key Words: hand-arm vibration syndrome (HAVS); mining; personal protective equipment (PPE); prevention; risk factors; tactometry; vibration

Introduction

In 1862 a French physician, Dr. Maurice Raynaud, identified a condition, now called Raynaud's Phenomenon, in which a blanching of the fingertips occurred with exposure to the cold.¹ A condition in which similar symptoms result from exposure to vibrating tools was first investigated in North America by Dr. Alice Hamilton in 1911.² It is known as hand-arm vibration syndrome (HAVS) or as Raynaud's Phenomenon of occupational origin, vibration-induced white finger (VWF), dead finger, traumatic vasospastic disease and vibration syndrome. HAVS is a complex syndrome caused by the constriction of blood vessels in the fingers, and involves circulatory, sensory, motor and musculoskeletal disturbances.³ The blanching of the fingertips becomes more frequent and severe with prolonged vibration exposure; continued exposure can extend the blanching along the length of all of the fingers and thumbs.

In mines, vibration exposure can result from the use of hand-held tools such as a jackleg drills, long-hole drills, stopers, various impact wrenches and smaller hand tools typically utilized on a daily basis. The jackleg drill is so named because it has a heavy metal support at the bottom that helps steady it as the miner is collaring the hole and provides leverage as the drill is being pressed forward.⁴ The jackleg drill is used to drill holes in the stope, a step-like excavation underground to mine vertical or steeply inclined deposits in successive layers where the broken ore can be drawn by gravity to prepare the rock for blasting. The long-hole drill is used in drifts, or horizontal passages underground, for the same purpose as the jackleg drill. A drift follows the vein, as distinguished from a crosscut that intersects it, or a level or gallery, which may do either.⁵ The stoper is similar to a jackleg drill in design but is used to drill into the ceiling of the area being blasted to allow protective bolting and screening to be applied to prevent loose rock from dropping and injuring the workers.⁶ The impact wrenches and hand tools are required for equipment maintenance and to change drill bits.

The prevalence of HAVS so concerned the miners at a northern Ontario base metal mine that the mine's joint health and safety committee asked the Occupational Health Clinics for Ontario Workers Inc. (OHCOW) to investigate. A multidisciplinary team of OHCOW staff and associates initiated, designed and carried out a study of HAVS among the mine workers intended to identify and provide a medical assessment for any worker who was willing to participate. A personal diagnostic report was provided to each participating worker and forwarded to his or her family physician with the worker's consent. An educational seminar was also held for miners, mine workers and interested members of the community on the health effects of vibration exposure, risks of future exposure, treatment, rehabilitation and disability-related benefits.

Methods

Study Population

This study was conducted at a base metal mine located in northern Ontario. Both management and union personnel agreed to work jointly with OHCOW to determine the prevalence of HAVS in the mine workers. The OHCOW team included occupational health physicians and nurses, an ergonomist, an occupational hygienist, an information technician, support staff and executive directors.

Phase I

A self-reported initial questionnaire was created for this project and was mailed to 617 workers who lived within a 100 km radius of the mine and were employed there from 1989 to 1994. The questionnaire was designed to identify those individuals who met the criterion of reported numbness (i.e., reduced sense of touch in one or more fingers, one or more times per week), parasthesias (i.e., tingling in one or more fingers, one or more times per week) or finger whitening. Of the 617 workers, 402 (65.2%) completed and returned the questionnaire.

Phase II

Two hundred and eighty-eight workers reported potential HAVS-like symptoms (e.g., finger numbness, parasthesia and finger whitening) and were sent a more extensive self-reporting questionnaire. This second questionnaire requested information on demographics, complete work history, medical history, lifestyle patterns and hobbies.

Phase III

The workers who had completed the second questionnaire were contacted and appointments were scheduled for tactometry testing and review of the second questionnaire by OHCOW staff. Of those 288 workers, 182 (63.2%) agreed to be assessed.

Phase IV

The grip strength, pinch grip testing and index finger temperature of each worker was recorded by OHCOW staff. Occupational health nurses recorded the results of each worker's blood pressure, Tinel and Phalen Tests, Dellon's Modified Pick-up, wrist extension and flexion (range of motion), and pulp-to-palm tests,* then reviewed each worker's history, blood pressure and test results with the OHCOW physician before he or she interviewed and examined the worker.

A diagnosis was made based on the findings from the testing performed as described in Phases III and IV, and the worker was advised. An individual consultation note was delivered to the worker and to the family physician with the worker's written consent. If the occupational health physician deemed it necessary, the family physician was informed of his or her recommendations for further diagnostic testing to determine the severity of the disease, methods of treatment, rehabilitation and disability-related benefits.

Phase V

A well-attended educational seminar was held at the local community centre for interested workers, family members and the general public. HAVS was explained in detail, as were its causes, diagnosis, treatment and prevention. A further discussion of the known health effects of smoking on the human body resulted in a recommendation that stopping smoking could reduce the severity of HAVS as well as improve a person's overall health. The seminar was followed by a question and answer period.

Phase VI

The data were entered into a FoxPro^®12 database. Statistical Package for the Social Sciences (SPSS^®)¹³, a comprehensive data analysis package for use in research and business, was used to tabulate frequencies, percentages and descriptive statistics.

Results

Of the 402 respondents to the first questionnaire, 288 (72%) reported potential HAVS-like symptoms. One hundred and eight-two (63%) participants were assessed. Prior to completion of the final phase of the study, 20 (11.0%) of the participants withdrew, mainly due to relocation to another community and/or employer. The results are reported for the 162 participants who completed all four phases of the study.

* The Tinel's sign is considered positive when the median nerve is tapped at the wrist⁷ and a tingling sensation is experienced in area(s) of the hand. Acute flexion of the wrist for 60 seconds (Phalen test) in some but not all patients or strenuous use of the hand increases the paresthesia.⁸ Dellon's Modified Pick-up Test requires increasing discrimination for object recognition.⁹ The Moberg Pick-up Test requires the subject to pick up a series of 10 to 12 small objects of various sizes from a table surface and place them in a small container.¹⁰ The wrist extension and flexion or range of motion of the wrists is measured in degrees with a goniometer, an instrument for measuring angles.¹¹ The pulp-to-palm test measures the ability of the patient to touch the palm of his or her hand with the third digit of that hand.

The demographics for the study participants appear in Table 1. The mean age for the group was 44.8 years (standard deviation 10.8) with approximately 22 years of employment and 15 years of vibratory tool use. Fourteen (8.6%) of the participants did not identify any use of vibrating tools. In these cases, the participant's current age was used as a surrogate for "age at first use (in years)", and "time since first use (in years)" and "use of vibrating tools (in years)" were considered to be nil.

With respect to diagnosis (Table 2), 81 (50.0%) of all participants were diagnosed with HAVS and 27 (16.7%) were diagnosed with CTS. Three participants (1.9%) were diagnosed with Raynaud's Phenomenon that was not due to hand-arm vibration exposure. Some participants experienced multiple afflictions raising the percentage to over 100.

The data for current/last job with the mine appear in Table 3. Most (136, 84.0%) of the participants held production or maintenance jobs, either underground or on the surface. Sixteen (9.9%) of the participants held management, supervisory or salaried positions. The remainder of the participants held a variety of jobs, including clerical and surface drivers.

Table 4 displays the differences between participants diagnosed with HAVS (n = 81) and those not diagnosed with HAVS (n = 81) in relation to their self-reported medical histories. For all the health-related conditions examined, those with HAVS more frequently reported health problems than those without HAVS. Thirty-two participants with HAVS (35.9%) had noise-induced hearing loss (NIHL) compared to 23 (28.4%) of unaffected participants. Participants with HAVS also reported a greater incidence of hypertension, diabetes, migraine and heart attack.

Diagnostic test results, which included index finger pad temperature and pinch and grip strength, showed no statistically significant differences between those diagnosed with HAVS and those without. Due to the study design, the differences between the HAVS and the non-HAVS group were insignificant.

The smoking histories of the participants appear in Table 6. Surprisingly, over 80% of all participants reported that they had smoked. Of the participants diagnosed with HAVS, 74 (91.4%) reported that they formerly smoked and 41(50.6%) reported that they were current smokers. As smoking is well known to have a vasoconstrictive effect on the peripheral vascular system, it is presumed that smoking may be a factor contributing to the development of VWF.¹⁴

The data on equipment and tool usage appear in Table 7. Over 60% of participants diagnosed with HAVS reported that they had used a jackleg drill; only 25% of those not diagnosed with HAVS reported having used this piece of equipment. Approximately two and a half times as many of the participants diagnosed with HAVS reported using a stoper than those who did not.

Discussion

This study was designed to be a screening tool for the detection of HAVS in miners. If the test results showed a possible diagnosis of HAVS, the workers were referred to their doctor for further testing in a vascular laboratory. Due to the design of the study, workers who reported no symptoms were not included in the testing and examination phases. The study was only able to show the prevalence of HAVS among the workers who completed the initial questionnaire on the possible symptoms of the syndrome.

At the mine studied, the miners were regularly required to use hand-held vibratory tools such as jackleg drills, long-hole drills, stopers, various impact wrenches and hand tools. Over the years, use of these tools can cause circulatory and neurological changes. The cold and wet underground mining environment is another consideration.¹⁵ On comparing the frequency of use of vibrating equipment, it was found that the workers suffering from HAVS operated equipment such as chainsaws and all-terrain vehicles (ATVs) more often. Although the findings were of interest, the study design did not allow conclusive analysis of these results.

It is apparent from the frequency of HAVS among workers exposed to vibrating equipment that technological improvements and education are required to reduce the prevalence of this syndrome in the mining industry. Anti-vibration devices such as rubber grips, anti-vibration gloves, and better tool design and maintenance should reduce the amount of vibration, as should keeping the hands warm and dry by wearing water-resistant gloves and maintaining core body temperature. It is known that the risk of HAVS increases with continuous exposure, length of exposure and a history of smoking. It is recommended that regular vibration-free periods (10 minutes per hour) be implemented, perhaps by alternating tasks with vibrating and non-vibrating tools. Workers should also be advised to grip the tool as lightly as possible, allowing the tool to do the bulk of the work.

Withdrawal from the source of the vibration appears to be the most effective way to halt, and in some cases reverse, the progression of HAVS. Avoidance of smoking is important as it represents a known aggravating factor and increases the severity of HAVS symptoms. The adoption of and adherence to threshold limit values (TLVs^®)¹⁶ developed as guidelines to assist in the control of health hazards, and vibration codes and standards have been recommended for the control and prevention of HAVS.¹⁷

Educational sessions are recommended for workers at risk, stressing the importance of using anti-vibration equipment to lessen the exposure. The sessions should include how to prevent HAVS from developing and, if a positive diagnosis has been made, how to prevent further deterioration. Other factors that impact on HAVS, such as smoking (vasoconstrictor), hobbies (hand tools, recreational vehicles) and medical conditions (hypertension, diabetes), should be discussed.

The National Institute for Occupational Safety and Health (NIOSH) recommends that occupational health professionals, workers and employers should consider the seriousness of HAVS. It also recommends that engineering controls, medical surveillance, work practices and personal protective equipment be used to reduce exposure to vibrating hand tools and to help identify HAVS in its early stages among workers likely to be at risk.¹⁸

Limitations

There were several limitations to this study that are worthy of mention. As the questionnaires were self-reported, it was difficult to obtain accurate and complete information on work exposures, personal protective equipment or personal and leisure activities. The design of the study limited accurate reporting because the questionnaire prompted the workers to add comments that could not be analyzed.

The mine at which the study was carried out was in a remote area of northeastern Ontario, was slated for closure and had a workforce that had already been significantly reduced. It was difficult to communicate with the workers, especially those who had found other employment and had relocated. The workers came from a variety of educational backgrounds; it is possible that some did not fully comprehend the questions, and their answers may not have been accurate. The initial screening was based on the workers' self-reported symptoms, which may not have been present or were not severe enough to be detected. The company was not requested to provide information on the condition or maintenance of the vibratory tools used in the mine, or on the monitoring of exposure to them. Neither the company nor the union was requested to provide information on due diligence or the monitoring of HAVS exposure. These factors did not permit precise data entry, which subsequently affected the results extracted from the database.

Acknowledgement

We would like to thank Dr. P. L. Pelmear for his very helpful advice.

References

1. Raynaud, M. Local Asphysia and Symmetrical gangrene of the extremities (MD Thesis). Paris, 1862, Translated into English by the New Sydenham Society and published in selective monographs. London, 1888.

2. Hamilton, A. A study of spastic anaemia in the hands of stonecutters. Ind. Accident Hyg. Services Bulletin 236, No. 19. U.S. Dept of Labor, Bureau of Labor Statistics 1918:53-66.

3. Occupational Health Clinics for Ontario Workers Inc. (OHCOW). Bulletin Hand-Arm Vibration Syndrome; Occupational Health Clinics for Ontario Workers Inc.; December 1998; p. 2.

4. Clement, W. Hardrock Mining: Industrial Relations and Technological Changes at INCO. Toronto: McClelland and Stewart Limited; 1981.

5. Pennsylvania Department of Environmental Protection, Bureau of Deep Mine Safety; Glossary of Mining Terms; http://www.dep.state.pa.us/dep/deputate/minres/dms/
website/training/glossary.html. Accessed October 26, 2001.

6. Clement, W., p. 109.

7. Andersen, JE. A Review and Case Study of Hand Arm Vibration Syndrome. Unpublished thesis for certification with the Canadian Board of Occupational Medicine; July 1994; p. 20.

8. Canale: Campbell's Operative Orthopaedics, Ninth Edition; 1998; St. Louis, MO: Mosby; Inc. p. 3685.

9. Pelmear, PL, Taylor, W, Wasserman, DE. Hand-Arm Vibration. A Comprehensive Guide for Occupational Health Professionals; Second Edition. USA: OEM Press; 1998; p. 86.

10. Pelmear, PL, Taylor, W, Wasserman, DE. p. 86.

11. Miller, BF, M.D., et al. Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Pennsylvania; W. B. Saunders and Company; 1978; p. 426.

12. Microsoft Inc. FoxPro; http://msdn.microsoft.com/vfoxpro/. Site accessed October 26, 2001.

13. SPSS Inc. SPSS 60606SPSS; Version 8.

14. Pelmear, PL,Taylor, W, Wasserman, DE. p. 56.

15. Ashe, WF. Occupational Raynaud's II. Archives of Environmental Health.1964; p. 425.

16. American Conference of Governmental Industrial Hygienists (ACGIH). Threshold Limit Values for Chemical Substances and Physical Agents. Cincinnati (Ohio): American Conference of Governmental Industrial Hygienists; 2000; Policy Statement.

17. Andersen, JE. p. 21.

18. National Institute for Occupational Safety and Health (NIOSH). Criteria for a Recommended Standard: Occupational Exposure to Hand-Arm Vibration. Cincinnati (Ohio); U.S. Department of Health and Human Services; September 1989; p. 104.

19. ICD-9-CM; International Classification of Diseases, 9^th Revision, 4^th Edition. Clinical Modification, Volumes 1, 2 & 3, 1992. Practice Management Information Corporation. Los Angeles (California); p. 247.

Author References

Joel Andersen, Donna M Campbell, Colleen E Hill, Wendy J Langis, John E Petherick, Occupational Health Clinics for Ontario Workers Inc., Sudbury, Ontario

Ted Haines, Occupational Health Clinics for Ontario Workers Inc., Hamilton, Ontario

Kevin K Conley, United Steelworkers of America Local 6500, Sudbury, Ontario

Randy J Bissett, Nancy E Lightfoot, Jason White, Northeastern Ontario Regional Cancer Centre, Sudbury, Ontario

Correspondence: Colleen Hill, Occupational Health Clinics for Ontario Workers Inc. (Sudbury), 1780 Regent Street South, Sudbury, Ontario P3E 3Z8; Fax: (705) 523-2606; E-mail: CHill@ohcow.on.ca

[Previous] [Table of Contents] [Next]