Quantifying relationships between selected work-related risk factors and back pain: a systematic review of objective biomechanical measures and cost-related health outcomes.

The objective of this investigation was to use published literature to demonstrate that specific changes in workplace biomechanical exposure levels can predict reductions in back injuries. A systematic literature review was conducted to identify epidemiologic studies which could be used to quantify relationships between several well-recognized biomechanical measures of back stress and economically relevant outcome measures. Eighteen publications, describing 15 research studies, which fulfilled search criteria were found. Quantitative associations were observed between back injuries and measures of spinal compression, lifting, lifting ratios, postures, and combinations thereof. Results were intended to provide safety practitioners with information that could be applied to their own work situations to estimate costs and benefits of ergonomic intervention strategies before they are implemented.

Estimating investment worthiness of an ergonomic intervention for preventing low back pain from a firm's perspective.

A mathematical model was developed for estimating the net present value (NPV) of the cash flow resulting from an investment in an intervention to prevent occupational low back pain (LBP). It combines biomechanics, epidemiology, and finance to give an integrated tool for a firm to use to estimate the investment worthiness of an intervention based on a biomechanical analysis of working postures and hand loads. The model can be used by an ergonomist to estimate the investment worthiness of a proposed intervention. The analysis would begin with a biomechanical evaluation of the current job design and post-intervention job. Economic factors such as hourly labor cost, overhead, workers' compensation costs of LBP claims, and discount rate are combined with the biomechanical analysis to estimate the investment worthiness of the proposed intervention. While this model is limited to low back pain, the simulation framework could be applied to other musculoskeletal disorders. The model uses Monte Carlo simulation to compute the statistical distribution of NPV, and it uses a discrete event simulation paradigm based on four states: (1) working and no history of lost time due to LBP, (2) working and history of lost time due to LBP, (3) lost time due to LBP, and (4) leave job. Probabilities of transitions are based on an extensive review of the epidemiologic review of the low back pain literature. An example is presented.

An intrinsic pattern of reduced susceptibility to fluoroquinolones in pediatric isolates of Streptococcus pyogenes.

A total of 116 clinical isolates collected in 2003 from a tertiary pediatric hospital and a primary pediatric department in Chicago, IL, were screened for reduced susceptibility to selected fluoroquinolones by disc diffusion. Correlation between reduced susceptibility and point mutations in the quinolone resistance-determining region of parC and gyrA genes was evaluated, and point mutations were compared with other reports of isolates derived from adult or mixed patient populations. Nine percent of isolates had reduced susceptibility to 1 or more of these fluoroquinolones by Etest: ciprofloxacin, levofloxacin, and moxifloxacin. A single point mutation (Ser-79) in parC seemed responsible for the reduced susceptibility. Resistant Streptococcus pyogenes isolates were compared using M/emm type, repetitive sequence-based PCR (rep-PCR), and pulsed-field gel electrophoresis (PFGE). Rep-PCR provided no more separation of strains than M/emm typing, and PFGE results with SgrAI were more discriminatory than with SmaI. The majority of these isolates were M/emm type 6. PFGE analysis using SgrAI demonstrated 2 different resistant strains among the M/emm type 6 isolates. The findings suggest that a population of S. pyogenes with an intrinsic reduced susceptibility to fluoroquinolones exists in pediatric clinical isolates. Monitoring of amino acid changes in both parC and gyrA will assist in the prediction of emergence of high-level fluoroquinolone resistance.

Identification and antimicrobial susceptibility of lactic acid bacteria from retail fermented foods.

One important safety criterion of using lactic acid bacteria (LAB) in food applications is to ensure that they do not carry transferable antimicrobial resistance (AR) determinants. In this study, 63 LAB belonging to six genera, Streptococcus, Lactobacillus, Lactococcus, Enterococcus, Leuconostoc, and Pediococcus, were recovered from 28 retail fermented food products in Maryland, identified to species with 16S-23S rRNA spacer PCRs, and characterized for antimicrobial susceptibility against eight antimicrobials. Besides intrinsic resistance to ciprofloxacin or vancomycin in some lactobacilli, tetracycline resistance was observed in two Streptococcus thermophilus isolates from one cheese and one sour cream sample and was associated with the presence of a nonconjugative tet(S) gene. The results indicated a low level of AR among naturally occurring and starter LAB cultures in fermented dairy and meat products in the United States; therefore, the probability for foodborne LAB to serve as reservoirs of AR is low. Further studies involving a larger sample size are needed to assess the potential risk of AR gene transfer from LAB in fermented food products.

Stressful psychosocial work environment increases risk for back pain among retail material handlers.

BACKGROUND: Back pain is a major source of lost work time. Occupational physical activity only accounts for a fraction of low back pain; therefore, there is growing interest in investigating other possible causes of back pain including the psychosocial work environment. METHODS: Material handlers (N = 6,311) in 160 newly opened stores were interviewed at study entry and approximately 6 months later. Factor analysis was used to reduce the 37 psychosocial questionnaire items to seven distinct factors. RESULTS: After adjusting for history of back problems and work-related lifting, risk of back pain was moderately increased among employees who reported high job intensity demands (odds ratio (OR) = 1.8), job dissatisfaction (OR = 1.7), and high job scheduling demands (OR = 1.6). CONCLUSIONS: Modification of the psychosocial work environment for material handlers in large retail stores may help reduce back pain among employees.

Predictors of shoulder and back injuries in nursing home workers: a prospective study.

BACKGROUND: Nursing assistants (NAs) working in nursing homes have among the highest back and shoulder injury rates in the US. Incidence, severity, and cost of non-traumatic soft tissue musculoskeletal disorders in the nursing home industry in Washington State are quite high. METHODS: To determine whether resident characteristics data reported on the Health Care Financing Administration Minimum Data Set (MDS) could be used as a surrogate measure of cumulative exposure to physical loads, we conducted an 18-month prospective study in one nursing home. RESULTS: The combined NA injury incidence rate (IR) was 45.8 self-reported back and shoulder injuries per 100 [FTE] workers per year. In general, MDS reported resident characteristics failed to predict risk with the exception of exposure to loss of voluntary leg mobility (OR = 1.11 per person-shifts of exposure, 95% CI [0.97-1.27]), with the highest risk on the day shift (OR = 1.15, 95% CI [0.95-1.40]). CONCLUSIONS: These findings suggest social integration and work organization issues may be more important predictors of back and shoulder injuries in nursing assistants than reported resident characteristics as measured by the MDS.