What is a demanding lifting job for manual handling workers in Hong Kong?

Evaluation of the Impact of the Revised National Institute for Occupational Safety and Health Lifting Equation

OBJECTIVE

The objective of this article is to evaluate the impact of the Revised National Institute for Occupational Safety and Health Lifting Equation (RNLE).

BACKGROUND

The RNLE has been used extensively as a risk assessment method for prevention of low back pain (LBP). However, the impact of the RNLE has not been documented.

METHODS

A systematic review of the literature on the RNLE was conducted. The review consisted of three parts: characterization of the RNLE publications, assessment of the impact of the RNLE, and evaluation of the influences of the RNLE on ergonomic standards. The literature for assessing the impact was categorized into four research areas: methodology, laboratory, field, and risk assessment studies using the Lifting Index (LI) or Composite LI (CLI), both of which are the products of the RNLE.

RESULTS

The impact of the RNLE has been both widespread and influential. We found 24 studies that examined the criteria used to define lifting capacity used by the RNLE, 28 studies that compared risk assessment methods for identifying LBP, 23 studies that found the RNLE useful in identifying the risk of LBP with different work populations, and 13 studies on the relationship between LI/CLI and LBP outcomes. We also found evidence on the adoption of the RNLE as an ergonomic standard for use by various local, state, and international entities.

CONCLUSION

The review found 13 studies that link LI/CLI to adverse LBP outcomes. These studies showed a positive relationship between LI/CLI metrics and the severity of LBP outcomes.

Perceived effort and low back pain in non-emergency ambulance workers: implications for rehabilitation

INTRODUCTION

This study aims to explore factors associated with low back pain (LBP) that required treatment from health care provider among non-emergency ambulance transfer workers.

METHOD

A cross-sectional study was conducted to 38 workers of a major hospital in Hong Kong. The influences of four categories of risk factors (personal, physical, psychosocial, and exposure factors) in the prevalence of LBP were investigated by objective measurement and self-reported questionnaires. A modified Nordic musculoskeletal symptoms survey and sick leave record were used to document the prevalence of LBP. Univariate analyses followed by multiple logistic regression analyses were used to explore the risk factors associated with LBP cases.

RESULTS

The results revealed that LBP was associated with age (OR=0.75, CI=0.56-1.00, P < 0.05), perceived effort (OR=7.95, CI=1.46-43.27, P < 0.05), job satisfaction (OR=4.18 CI=1.42-12.33, P < 0.01), and flexor peak torque at 120 degrees /s (OR=1.09 CI= 0.99-1.19, P=0.07).

CONCLUSION

This study suggests that workers' perceived exertion has an valuable role in assessing risk at this workplace. A high perceived exertion at work can signal the need for work adjustment or modification to avoid progression of low back disorder to persistent pain or intense pain. The effects of work adjustment or modification in affected workers needs to be systematically investigated.

Determinants of the progression in lumbar degeneration: a 5-year follow-up study of adult male monozygotic twins

STUDY DESIGN

A 5-year follow-up study of exposure of discordant monozygotic twin pairs with repeated interviews and spine imaging.

OBJECTIVE

The primary goals were to record changes in the degenerative signs over a 5-year interval and to estimate the effects of familial influences and suspected environmental risk factors on the speed of lumbar degeneration.

SUMMARY OF BACKGROUND DATA

Traditionally, disc degeneration has been attributed to aging and environmental exposures; recently, a dominant effect of genetics has been revealed. Yet the etiopathogenesis of disc degeneration remains poorly understood and controversial despite being a primary target of diagnostic and therapeutic interventions.

METHODS

Among 116 monozygotic twin pairs, which had been examined 5 years earlier, 75 pairs (150 men) were reexamined. They were imaged using the same MRI scanner and examination protocol as at baseline. The data were analyzed using statistical methods for longitudinal studies.

RESULTS

Progression in disc height narrowing, disc bulging, osteophytosis, and fatty degeneration in the lumbar spine was seen in about 7% to 13% of the discs in 7% to 46% of subjects during 5-year follow-up. Few degenerative findings appear to reverse; few disc height measures increased, some anular tears were no longer visible, and bulging/herniation diminished. New anular tears (in axial view) were detected in 1.5%, disappeared in 2%, and were unchanged in 5.3% of discs; in the sagittal view, new high intensity zones findings were identified in 0.5%, were no longer apparent in 1.6%, and were unchanged in 7.1% of discs. There were no clear changes in upper endplates: in 2.1% of discs, the irregularity score increased and in 1.8% it decreased. Familial aggregation, reflecting genetic, and shared environmental influences, explained 47% to 66% of the variance in progression of degenerative signs on lumbar MRI, and resistance training and occupational physical loading together explained 2% to 10% of the progression in the degenerative signs in lumbar MRIs.

CONCLUSIONS

Progression of disc height narrowing, bulging, osteophytes, and fatty degeneration was detected in about 10% or less of the T12-S1 discs. Development and disappearance of anular lesions were rarer. No clear changes were seen in endplate irregularities. The results also confirm that hereditary effects have a dominant role in the progression of disc degeneration and suggest that occupational lifting and leisure time resistance training have modest additional effects.

A participatory approach to the study of lifting demands and musculoskeletal symptoms among Hong Kong workers

AIMS

To investigate the use of a worker based methodology to assess the physical stresses of lifting tasks on effort expended, and to associate this loading with musculoskeletal outcomes (MO).

METHODS

A cross sectional study was conducted on 217 male manual handling workers from the Hong Kong area. The effects of four lifting variables (weight of load, horizontal distance, twisting angle, and vertical travel distance) on effort were examined using a linguistic approach (that is, characterising variables in descriptors such as "heavy" for weight of load). The numerical interpretations of linguistic descriptors were established. In addition, the associations between on the job effort and MO were investigated for 10 body regions including the spine, and both upper and lower extremities.

RESULTS

MO were prevalent in multiple body regions (range 12-58%); effort was significantly associated with MO in 8 of 10 body regions (odds ratios with age adjusted ranged from 1.31 for low back to 1.71 for elbows and forearm). The lifting task variables had significant effects on effort, with the weight of load having twice the effect of other variables; each linguistic descriptor was better described by a range of numerical values rather than a single numerical value.

CONCLUSIONS

The participatory worker based approach on musculoskeletal outcomes is a promising methodology. Further testing of this approach is recommended.