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Biomedical subjects

L Punnett

Publications and source records attributed to L Punnett.

At least 19 recordsLinked to original sources
PubMed2006

Hospital injury rates in relation to socioeconomic status and working conditions.

OBJECTIVES: To describe the risk of work injury by socioeconomic status (SES) in hospital workers, and to assess whether SES gradient in injury risk is explained by differences in psychosocial, ergonomic or organisational factors at work. METHODS: Workforce rosters and Occupational Safety and Health Administration injury logs for a 5-year period were obtained from two hospitals in Massachusetts. Job titles were classified into five SES strata on the basis of educational requirements and responsibilities: administrators, professionals, semiprofessionals, skilled and semiskilled workers. 13 selected psychosocial, ergonomic and organisational exposures were assigned to the hospital jobs through the national O*NET database. Rates of injury were analysed as frequency records using the Poisson regression, with job title as the unit of analysis. The risk of injury was modelled using SES alone, each exposure variable alone and then each exposure variable in combination with SES. RESULTS: An overall annual injury rate of 7.2 per 100 full-time workers was estimated for the two hospitals combined. All SES strata except professionals showed a significant excess risk of injury compared with the highest SES category (administrators); the risk was highest among semiskilled workers (RR 5.3, p<0.001), followed by nurses (RR 3.7, p<0.001), semiprofessionals (RR 2.9, p = 0.006) and skilled workers (RR 2.6, p = 0.01). The risk of injury was significantly associated with each exposure considered except pause frequency. When workplace exposures were introduced in the regression model together with SES, four remained significant predictors of the risk of injury (decision latitude, supervisor support, force exertion and temperature extremes), whereas the RR related to SES was strongly reduced in all strata, except professionals. CONCLUSIONS: A strong gradient in the risk of injury by SES was reported in a sample population of hospital workers, which was greatly attenuated by adjusting for psychosocial and ergonomic workplace exposures, indicating that a large proportion of that gradient can be explained by differences in working conditions.

Accidents, Occupational↗
PubMed2005

Digital vibration threshold testing and ergonomic stressors in automobile manufacturing workers: a cross-sectional assessment.

Upper extremity musculoskeletal disorders (UEMSDs) comprise a large proportion of work-related illnesses in the USA. Physical risk factors including manual force and segmental vibration have been associated with UEMSDs. Reduced sensitivity to vibration in the fingertips (a function of nerve integrity) has been found in those exposed to segmental vibration, to hand force, and in office workers. The objective of this study was to determine whether an association exists between digital vibration thresholds (VTs) and exposure to ergonomic stressors in automobile manufacturing. Interviews and physical examinations were conducted in a cross-sectional survey of workers (n = 1174). In multivariable robust regression modelling, associations with workers' estimates of ergonomic stressors stratified on tool use were determined. VTs were separately associated with hand force, vibration as felt through the floor (whole body vibration), and with an index of multiple exposures in both tool users and non-tool users. Additional associations with contact stress and awkward upper extremity postures were found in tool users. Segmental vibration was not associated with VTs. Further epidemiologic and laboratory studies are needed to confirm the associations found. The association with self-reported whole body vibration exposure suggests a possible sympathetic nervous system effect, which remains to be explored.

Adult↗
PubMed2004

Ergonomic stressors and upper extremity musculoskeletal disorders in automobile manufacturing: a one year follow up study.

AIMS: To estimate the one year cumulative incidence and persistence of upper extremity (UE) soft tissue disorders, in a fixed cohort of automotive manufacturing workers, and to quantify their associations with ergonomic exposures. METHODS: At baseline and at follow up, cases of UE musculoskeletal disorders were determined by interviewer administered questionnaire and standardised physical examination of the upper extremities. The interview obtained new data on psychosocial strain and updated the medical and work histories. An index of exposure to ergonomic stressors, obtained at baseline interview, was the primary independent variable. Cumulative incidence and persistence of UE disorders (defined both by symptoms and by physical examination plus symptoms) were analysed in relation to baseline ergonomic exposures, adjusting for other covariates. The incidence of new disorders was modelled using multivariate proportional hazards regression among workers who were not cases in the first year and the prevalence on both occasions was modelled by repeated measures analysis. RESULTS: A total of 820 workers (69% of eligible cohort members) was examined. Follow up varied slightly by department group but not by baseline exposure level or other characteristics. Among the non-cases at baseline, the cumulative incidence of UE disorders was 14% by symptoms and 12% by symptoms plus examination findings. These rates increased with index of physical exposures primarily among subjects who had the same jobs at follow up as at baseline. Increased exposure during follow up increased risk of incidence. The persistence of UE disorders from baseline to follow up examination was nearly 60% and somewhat associated with baseline exposure score. CONCLUSIONS: These longitudinal results confirm the previous cross sectional associations of UE musculoskeletal disorders with exposure to combined ergonomic stressors. The exposure-response relation was similar for incident cases defined by symptoms alone and those confirmed by physical examination.

Adult↗
PubMed2001

Covariation between workplace physical and psychosocial stressors: evidence and implications for occupational health research and prevention.

There is increasing interest in distinguishing the effects of physical and psychosocial workplace stressors on the aetiology of work-related musculoskeletal disorders (MSD). Modest associations have been found between psychosocial stressors and MSD, such as intensive load, monotonous work and low job control. Interpretation of these results has been limited by likely covariation between physical and psychosocial stressors. This investigation examined exposure covariation among blue- and white-collar workers employed in a mass production manufacturing environment (N = 410). Physical stressors were assessed from questionnaire and accelerometry. Psychosocial stressors were assessed from questionnaire. Pearson and Spearman correlation coefficients were computed. An exploratory factor analysis procedure identified possible common factors linking specific physical and psychosocial stressors. Moderate to high correlations between some physical and psychosocial stressors showed evidence of covariation both across and within groups. Covariation was strongest among blue-collar production and low-status office workers. Factor analysis results showed considerable shared variance between some physical and psychosocial stressors, such as repetition and job control, suggesting that these disparate stressors manifest from common work organization factors that govern the structure of work. While recognizing the conceptual differences between physical and psychosocial stressors, these results call attention to the strong empirical relationships that can exist between some stressors in the workplace setting. To guard against ambiguous study findings that can occur when exposures are mixed, it is critical that future epidemiologic studies include information about the degree of association between task-level stressors. Future research on work organization determinants of task-level stressors, and their coincident occurrence in jobs with greater specialization, may provide promising new insights into the nature of risk for MSD and effective prevention strategies.

Adult↗
PubMed2001

Surveillance of work-related carpal tunnel syndrome in Massachusetts, 1992-1997: a report from the Massachusetts Sentinel Event Notification System for Occupational Risks (SENSOR).

BACKGROUND: This surveillance study was undertaken to target efforts to prevent work-related carpal tunnel syndrome (WR-CTS) and to assess physician case-reports as a source of surveillance data. METHODS: Physician case-reports and workers' compensation disability claims were used to document patterns of WR-CTS in Massachusetts from March 1992 to June 1997 by age, gender, industry, occupation, and calendar year. Characteristics of cases identified through the two data sources were compared. RESULTS: 4,836 cases of WR-CTS were ascertained; 6% were identified by both data sources. Whereas the two sets of cases were similar with respect to age and occupation categories, physician-reported cases were more likely male and employed in manufacturing. The number of compensation claims filed by women declined over time, and a substantial number of cases under age 25 years were identified. Manufacturing workers had the highest rates; the highest numbers of cases were employed in hospitals, grocery stores, and the insurance industry. Several technical/administrative support occupations likely to use video display terminals had both high rates and frequencies. CONCLUSION: WR-CTS is a significant public health problem. Physician reports are useful in understanding problem magnitude and targeting specific establishments for intervention but are currently of limited use in targeting specific industries and occupations.

Administrative Personnel↗
PubMed2001

Validity of fixed-interval observations for postural assessment in construction work.

While observing six simulated construction tasks in the field, trained analysts recorded arm, trunk and leg postures categorically with two fixed-interval observational protocols. Observations were compared to measurements obtained with an electronic postural assessment system coupled with video analysis. The electronic postural assessment system consisted of electronic inclinometers to measure upper arm posture, knee flexion and trunk flexion, coveralls to house the inclinometer wiring, and an eletrogoniometric system to measure trunk lateral bending and twisting. Video analysis included frozen-frame analysis that corresponded to the moment of observation and simulated real-time analysis. Measurements were made on five male participants who each performed three tasks representative of construction laborers' work. Agreement among the observational and reference methods was generally high, although significant differences in measured frequency of exposure existed for knee flexion, trunk lateral bending and trunk twisting. The results suggest that, under appropriate conditions, discrete observations can be used to obtain reasonably accurate estimates of exposure frequency for broad categories of certain body postures.

Humans↗
PubMed2001

Effects of drop out in a longitudinal study of musculoskeletal disorders.

OBJECTIVES: The drop out rates in different longitudinal studies of musculoskeletal disorders range between 7% and 57%, and little is known about the characteristics of the subjects who dropped out. The aim was to analyse various consequences of drop out in a longitudinal study of musculoskeletal disorders and occupational risk factors during 1969-97. METHOD: Data about occupational conditions and health in 1969 and in 1993 were analysed. Differences between those who participated throughout (participants) and drop out subjects in these analyses formed the basis for recalculations of earlier reported analyses of associations between occupational conditions and low back pain. In the recalculation the data were weighted to compensate for the differences. RESULTS: More female and male drop out subjects than participants in 1993 had monotonous work, fewer women and more male drop out subjects had heavy lifting in 1969. In 1997, more female and male drop out subjects had had heavy lifting and low stimulation at work in 1993. At both occasions, there were differences between the drop out subjects and participants in occurrence of musculoskeletal disorders. The weighted analyses resulted in changes in risk ratio of 0.1-0.2. CONCLUSIONS: Differences in occupational conditions and health among participants and drop out subjects in a longitudinal study of musculoskeletal disorders and occupational risk factors during 1969-97 did not markedly influence the risk ratios.

Adolescent↗
PubMed2000

Physical and psychosocial factors related to low back pain during a 24-year period. A nested case-control analysis.

STUDY DESIGN: A retrospective nested case-control study. OBJECTIVES: To identify occupational factors related to low back pain, and to study how interactions between psychosocial and physical factors, and between work-related and leisure-related factors affect low back pain in women and men. SUMMARY OF BACKGROUND DATA: A cohort of 484 subjects drawn from the general population was examined in 1969 and 1993, with a focus on occupational working conditions and musculoskeletal disorders. METHODS: Information about the physical and psychosocial working conditions and low back pain during the period 1970 to 1993 was collected retrospectively. Odds ratios and confidence intervals were calculated for different potential risk factors. RESULTS: During the 24-year period, 46% of the subjects became patients with low back pain. Among women, heavy physical workload, sedentary work, smoking, and the combination of whole-body vibrations and low influence over work conditions were associated with an excess risk of low back pain. Among men, excess risk for low back pain was seen in heavy physical workload, sedentary work, high perceived load outside work, and the combination of poor social relations and overtime. CONCLUSIONS: Factors at work were seen to be risk indicators for low back pain among both genders. Low influence over work conditions among women and poor social relations at work among men, in combination with other factors, seem to be of high relevance for the occurrence of low back pain.

Adolescent↗
PubMed2000

A comparison of approaches to modeling the relationship between ergonomic exposures and upper extremity disorders.

BACKGROUND: For a study of upper extremity musculoskeletal disorders among automobile manufacturing workers, an ergonomic exposure index was constructed by summing ten psychophysical (interview) items. Here we explore the sensitivity of the exposure-response relationship to the formulation of that index. METHODS: Five alternative exposure indices were constructed: three a priori weighting schemes and two sets of weights derived from multivariate regression coefficients. In addition, structural equation modeling was performed with LISREL. RESULTS: The original index and a priori weighting schemes had similar associations with upper extremity disorders, adjusted for nonoccupational covariates. A reasonable model fit was achieved in LISREL after two modifications; the standardized solution showed that nonneutral postures were significantly related to upper extremity signs and symptoms. CONCLUSIONS: In this large population, with adequate range of exposures, the exposure-response relationship appeared generally robust to the mathematical formulation of the exposure index. Among the available exposure variables, postural strain had the strongest association.

Adult↗
PubMed2000

Risk factors for neck and shoulder disorders: a nested case-control study covering a 24-year period.

BACKGROUND: In 1969 a population-based study was conducted in the Stockholm region. From the 2,579 randomly selected participants (18-65 years of age in 1969), the youngest subset were asked to participate in a reexamination in 1993. Information regarding working conditions, conditions outside work, and neck and shoulder disorders was collected retrospectively for the period 1970-1993. METHODS: Of 783 eligible subjects (42-59 years of age in 1993), 484 responded. Cases of neck/shoulder disorders were defined by past sick leave or medical attention or recent symptoms, depending on available information. For each case (n = 271) two controls were randomly selected, matched by age and gender. Variables regarding both physical and psychosocial conditions were included in the matched analyses. RESULTS: Among women mainly psychosocial factors and among men mainly physical factors were associated with neck/shoulder disorders. The only gender common risk indicator found was repetitive hand work (OR approximately 1.5). Interactive effects were also observed. CONCLUSIONS: The impact on neck/shoulder disorders from separate factors was moderate but combinations of physical and psychosocial factors, as well as of work-related and non-work-related factors, produced relative risks above 2.

Adult↗
PubMed2000

Shoulder disorders and postural stress in automobile assembly work.

OBJECTIVES: A case-referent study was conducted in an automobile assembly plant to evaluate the risk of shoulder disorders associated with nonneutral postures. METHODS: The cases were workers who reported shoulder pain to the plant clinic during a 10-month period and met symptom criteria (pain frequency or duration in the past year) in an interview; more than one-half also had positive findings in a physical examination. The referents were randomly selected workers who were free of shoulder disorders according to the clinic records, the interview, and the physical examination. For each of the 79 cases and 124 referents, 1 job was analyzed for postural and biomechanical demands by an analyst blinded to the case-referent status. RESULTS: Forty-one percent of the subjects flexed or abducted the right arm "severely" (above 90 degrees) during the job cycle, and 35% did so with the left arm. The peak torques at the shoulder were rather low. Shoulder disorders were associated with severe flexion or abduction of the left [odds ratio (OR) 3.2, 95% confidence interval (95% CI) 1.5-6.5] and the right (OR 2.3, 95% CI 1.2-4.8) shoulder. The risk increased as the proportion of the work cycle exposed increased. The relationships were similar for the cases with and without physical findings. Use of hand-held tools increased the risk and also modified the association with postural stress, although the joint exposure distributions limited full analysis of this finding. CONCLUSIONS: The findings support the conclusion that severe shoulder flexion or abduction, especially for 10% or more of the work cycle, is predictive of chronic or recurrent shoulder disorders.

Adult↗
PubMed1999

Physical capacity in relation to present and past physical load at work: a study of 484 men and women aged 41 to 58 years.

BACKGROUND: A negative association has previously been reported between long-lasting physically heavy work and some measures of physical capacity. This relationship was further investigated in a 24-year follow-up study of 484 middle-aged men and women from the general population. METHODS: A questionnaire was administered in 1993 concerning retrospective recall of physical work loads and physical training in the time span between 1970 and 1993. Laboratory tests performed in 1993 included tests of muscle function (maximal isometric strength and dynamic endurance) and aerobic power (submaximal ergometer test). RESULTS: Consistent with the hypothesis, but mainly among the women, associations between long-lasting physically heavy demands and low trunk flexion strength, squatting endurance, and aerobic power were observed. In contrast, low isometric hand grip strength and low weight lifting endurance were seldom seen among those with high physical work loads, indicating a possible maintaining or training effect on the hand/arm/shoulder muscle groups. CONCLUSIONS: Physically heavy work seems to have a different impact on different parts of the musculoskeletal system, an effect that is also different between men and women.

Adult↗
PubMed1999

Evaluation of interrater reliability for posture observations in a field study.

This paper examines the interrater reliability of a quantitative observational method of assessing non-neutral postures required by work tasks. Two observers independently evaluated 70 jobs in an automotive manufacturing facility, using a procedure that included observations of 18 postures of the upper extremities and back. Interrater reliability was evaluated using percent agreement, kappa, intraclass correlation coefficients and generalized linear mixed modeling. Interrater agreement ranged from 26% for right shoulder elevation to 99 for left wrist flexion, but agreement was at best moderate when using kappa. Percent agreement is an inadequate measure, because it does not account for chance, and can lead to inflated measures of reliability. The use of more appropriate statistical methods may lead to greater insight into sources of variability in reliability and validity studies and may help to develop more effective ergonomic exposure assessment methods. Interrater reliability was acceptable for some of the postural observations in this study.

Analysis of Variance↗
PubMed1999

The costs of work-related musculoskeletal disorders in automotive manufacturing.

Inadequate application of ergonomic principles to the design of workplaces and individual jobs has adverse consequences for worker health and safety, especially in terms of strains, sprains, and other musculoskeletal disorders. In addition to the human pain and suffering, other losses are externalized to workers, with adverse financial and psychosocial impacts. There are also costs to employers through workers' compensation claims, scrap, and decreased production quality, medical insurance premiums, labor turnover, and adverse impacts on labor relations, although many of these are not linked by traditional accounting methods to ergonomic problems per se. Data collected in five plants of two major U.S. automotive manufacturing companies in the last decade have been used to estimate some of the costs associated with work-related musculoskeletal disorders (MSDs), only some of which resulted in workers compensation claims. In one plant in 1984-85, the payroll cost of all back and shoulder disorders was at least $320 per year per worker, not including workers' compensation premiums or claims paid. A large proportion of these costs were accrued by "unreported" cases, that is, cases that either had never been reported to the plant clinic or had been reported in the past and were considered administratively to have recovered. In the other four plants, annual costs associated with in-plant medical visits for MSDs in 1989-93 were almost as high as those resulting from compensation claims. At least one-half of these disorders were estimated to be attributable to physical ergonomic exposures in the workplace and thus preventable. These data are consistent with estimates by others that the real costs to employers are at least two to three times the amount paid in workers' compensation cases, and that at least 50 percent of all work-related musculoskeletal disorders among the working population could be prevented by appropriate ergonomic job design. Furthermore, recent experience with ergonomics programs in various manufacturing and service settings shows that they are cost-effective in reducing morbidity, work absenteeism, and workers' compensation claims; payback periods for workplace modifications can be as short as a few months. Further investigations should explore the reasons that monetary costs and other impacts on profitability do not always motivate employers to improve working conditions.

Journal Article↗
PubMed1999

Effects of an ergonomic training program on workers with video display units.

OBJECTIVES: This study evaluated the effect of an ergonomic training program on workstation changes and on the prevalence of musculoskeletal disorders among video display unit (VDU) users at a large university. METHODS: A pretest-posttest design with a reference group was used with random allocation of administrative and geographic units. In each group, the measurements involved direct observation of the workstations, a self-administered questionnaire, and a physical examination. The measurements were performed 2 weeks before and 6 months after the training in parallel in both groups. The study population was composed of 627 workers (81% of those eligible). RESULTS: The prevalence of all 3 of the postural stressors evaluated decreased in the experimental group after the training. In the reference group, 2 of the 3 stressors decreased in frequency but to a less extent. Some of these beneficial changes were more frequent in workers under 40 years of age. The prevalence of musculoskeletal disorders decreased among the workers under 40 years of age in the experimental group, from 29% to 13% determined by questionnaire and from 19% to 3% determined by physical examination. In other groups, there was no significant change in the prevalence of musculoskeletal disorders. CONCLUSIONS: Improvements in postural stressors occurred more frequently in the experimental group, and these beneficial changes tended to be more frequent in workers under 40 years of age. Improvements in musculoskeletal disorders occurred in the experimental group among the workers under 40 years of age.

Adult↗