Hendriek C. Boshuizen

Self-reported back pain in tractor drivers exposed to whole-body vibration

SummaryA postal questionnaire on symptoms of ill health and exposure to whole-body vibration was completed by 577 workers (response rate 79%) who were employed in certain functions by two companies 11 years before. The relation between the occupational history of driving vibrating vehicles (mainly agricultural tractors) and back pain has been analyzed. The prevalence of reported back pain is approximately 10% higher in the tractor drivers than in workers not exposed to vibration. The increase is mainly due to more pain in the lower back and more pain lasting at least several days. A vibration dose was calculated by assigning each vehicle driven a vibration magnitude, estimated on the base of vibration measurements. The prevalence of back pain increases with the vibration dose. The highest prevalence odds ratios are found for the more severe types of back pain. These prevalence odds ratios do not increase with the vibration dose. This might be due to health-related selection which is more pronounced for severe back pain than for back pain in general. The two components of the vibration dose, duration of exposure and estimated mean vibration magnitude, have also been considered separately. Back pain increases with duration of exposure but it does not increase with the estimated mean magnitude of vibration. This is probably due to the inaccuracy of this estimate. The higher prevalence of back pain in tractor drivers might be (partly) caused by whole-body vibration, but prolonged sitting and posture might also be of influence.

Self-reported Back Pain in Fork-lift Truck and Freight-container Tractor Drivers Exposed to Whole-body Vibration

To study the long-term health effect of whole-body vibration, a questionnaire on symptoms of ill health was mailed to 242 drivers and a reference group of 210 workers from six harbor companies (response 81%). Vehicles driven were fork-lift trucks and freight-container tractors. Vibration level during a representative working period (vector sum of the frequency weighted acceleration in the x-, y-, and z-directions) was 0.8 m/sec2 for the fork-lift trucks and 1.0 m/sec2 for the freight-container tractors. Only the results concerning self-reported symptoms of the back are described. Of the young (<35 years), shortterm-exposed drivers, 68% reported that they had back pain regularly vs. only 25% of the reference group of comparable age. With increasing age, the difference in the prevalence of self-reported regular back pain between the drivers and the reference group disappeared. Driving during the 5 years preceding the onset of symptoms seemed to increase the risk of back pain, whereas earlier exposure did not.

Do smokers get more back pain

Recently smoking has been increasingly implicated as a possible risk factor for low-back pain. One explanation for this finding is confounding by occupation. To investigate this possibility, the relationship between smoking and self-reported back pain was studied within 13 occupations. A relationship between smoking and back pain was observed only in occupations that require physical exertion. The relationship between smoking and other musculoskeletal pain also was explored. Pain in the extremities turned out to be related more clearly to smoking than to pain in the neck or the back. This suggests confounding or a general influence of smoking on pain. It is concluded that prevention of back pain could be a beneficial side-effect of anti-smoking campaigns. However, the prime target for prevention of low-back pain would have to be other factors.

Back disorders in crane operators exposed to whole-body vibration

SummaryIn The Netherlands so far little research has been carried out to investigate the health effects of exposure to whole-body vibration at work. In a retrospective (10-year) follow-up study, the incidence of permanent work disabilities in crane operators exposed to vibration was compared to that of a control group. The emphasis in this presentation is on disablement because of back disorders. Among the crane operators with more than 5 years of exposure to vibration, more disability due to back trouble occurred than in the control group. The incidence density ratio (IDR) exceeded 2 for disability because of degeneration of the intervertebral disc, after adjustment for age, nationality, shift work and calendar year. With increasing years of exposure, the risk ratio for disability because of intervertebral disc disorders also increased. The risk ratio for a disability pension due to disease of the intervertebral disc for crane operators with more than 5 years of exposure was almost 3 compared to the control group. A combination of exposure to whole-body vibration, an unfavorable posture, and climatic conditions is responsible for the development of these health effects.

Effect of sporting activity on absenteeism in a working population

Objectives: To determine the effects of sporting activity on absenteeism in a working population. Methods: Data were used from a prospective cohort study in a working population with a follow up period of 3 years and were collected with yearly questionnaires or collected from company records. Complete data on absenteeism, sporting activity, and potential confounders were collected for 1228 workers. ANOVA was used to test differences in frequency and duration of absenteeism, correlations were computed to measure the association between number of sporting years (divided by age) and frequency and duration of absenteeism, and survival analysis, according to the Cox proportional hazards model, was used to test differences in relative risk at absenteeism and recovery. All analyses were adjusted for age, gender, smoking, and alcohol consumption, and were stratified for employees with sedentary and with more active jobs. Results: ANOVA showed a statistically significant higher mean duration of absenteeism among employees not practicing sports, of approximately 20 days over a period of 4 years. The survival analysis showed an increased relative risk at absenteeism (relative risk (RR) 1.09; confidence interval (CI) 1.01 to 1.18) and a decreased relative risk at recovery (RR 0.90; CI 0.85 to 0.95) for employees not practicing sports. The effect of sporting activity is larger in employees with sedentary work. No associations were found between number of sporting years and absenteeism. Conclusion: Employees practicing sports take sick leave significantly less often than their colleagues not practicing sports, while their periods of sick leave are shorter, especially when their work is sedentary.

Long-term sick leave and disability pensioning due to back disorders of tractor drivers exposed to whole-body vibration

SummaryIn a historical 11-year follow-up study, disability pensioning and the incidence of the first sick leave of 4 weeks or longer due to back disorders has been investigated in a group of drivers exposed to whole-body vibration (WBV), mainly of agricultural tractors. The reference group comprised workers not or only slightly exposed to WBV from the same and another company. The vibration exposure of the tractor drivers was roughly around the ISO-2631 fatigue-decreased proficiency limit. The incidence of a first long-term sick leave due to back disorders was 3 per 100 person-years in tractor drivers and 2 per 100 person-years in the entire reference group. However, the incidence was not substantially increased in tractor drivers when the referents comprised only those working at the same company, suggesting selection bias. The highest relative risk (ca. 3) was found for long-term sick leave due to intervertebral disc disorders and this risk seemed to increase with the received WBV dose. That especially the incidence of intervertebral disc disorders increased, agrees well with findings in other studies. Data on disability pensioning due to back disorders are too scarce to be conclusive, but a trend towards younger disablement in tractor drivers is evident. Exposure to WBV, together with twisted posture and prolonged sitting, are considered to be responsible for the increased incidences observed in tractor drivers.

Long-term sickness absence due to back disorders in crane operators exposed to whole-body vibration.

SummaryIn a retrospective (10-year) follow-up study, the incidence of at least one spell of sickness absenteeism of 28 d or longer in crane operators exposed to whole-body vibration and a control group was investigated. In contrast to a previous study on permanent work disability in the same groups, no difference was observed in long-term sickness absenteeism because of lumbar disorders. Spells of sickness absence due to intervertebral disc disorders did last longer in the index group and also more disability pensions with this diagnosis were recorded in the index group. This indicates that these disorders particularly interfere with the work of a crane operator. Exposure to whole-body vibration and strained posture are considered to be responsible for this situation.

Back disorders and occupational exposure to whole-body vibration

Abstract During the past five years, a number of epidemiological studies on occupational exposure to whole-body vibration have been carried out at the Coronel Laboratory. These studies include both retrospective follow-up studies on long-term sick leaves and disability pensioning among crane-operators ( N = 1,084 ) and tractor drivers ( N = 423 ) and questionnaire studies on the prevalence of back pain among tractor drivers ( N = 455 ), helicopter pilots ( N = 133 ) and lift-truck drivers ( N = 233 ). Measurements (according to the ISO 2631 (1985)) were conducted to establish the accelation levels of the tractors, the helicopters and the lift-trucks. The prevalence of back pain, in most studies, was significantly higher among workers exposed to whole-body vibration compared to workers not exposed to whole-body vibration. Incidence rates of sick leave and disability pensioning due to back disorders, in particular intervertebral disc disorders, were in some studies higher in occupations that expose workers to whole-body vibration. The relationship between the received vibration dose and the prevalence of back pain as observed in these studies is explored.

Longitudinal Associations Between Physical Load and Chronic Low Back Pain in the General Population The Doetinchem Cohort Study

Study Design. Prospective cohort study. Objective. We explored long-term associations between physical load exposure and chronic low back pain (LBP) using data from an ongoing population-based cohort study. Summary of Background Data. Physical load in work or daily life is often studied in relation to LBP. Most studies are cross-sectional or have a limited follow-up. Methods. Between 1993 and 2007, 4738 men and women aged 25 to 64 years were measured maximal 3 times with 5-year intervals. Physical load in daily activities (9 items, e.g., awkward postures, mechanical vibration) was assessed by questionnaire at 2 measurements and chronic LBP 3 times. Physical load exposure at both measurements was described. Multivariable logistic regression analyses were adjusted for sex, age, education, work status, body mass index, physical activity, and smoking. Results. Despite stable prevalence rates of physical load exposure, about 50% of the participants exposed changed their exposure during a 5-year period. 7.2% of the participants reported awkward postures at 2 measurements, 8.4% at the first measurement only, and 6.8% at the second measurement only. Among all physical load variables, associations with chronic LBP were found only for awkward postures. An increased risk for incident chronic LBP was found in participants exposed twice to awkward postures. In contrast, only single exposure to awkward postures was associated with persistence of chronic LBP. Conclusion. Awkward postures were associated with chronic LBP in the general population. Exposure to awkward postures at 2 measurements with 5 years in between did increase the risk for incident chronic LBP, but not for persistence of chronic LBP.