Stefano Mattioli

Associations of Psychosocial and Individual Factors with Three Different Categories of Back Disorder among Nursing Staff

Associations of Psychosocial and Individual Factors with Three Different Categories of Back Disorder among Nursing Staff: Francesco S. Violante, et al. Alma Mater Studiorum—University of Bologna, Occupational Medicine Unit, Sant’Orsola‐Malpighi Hospital, Italy—Although back disorders are a major occupational problem for nursing staff, few studies distinguish different types. By means of a structured questionnaire, we performed a cross‐sectional study on the prevalence of diagnosed lumbar disc hernia, chronic low‐back pain (LBP) (at least 90 d in the preceding 12 months) and acute LBP (intense pain for at least 1 d) with respect to physical, individual and psychosocial factors among female nurses (n=587), nursing aides (n=228) and head‐nurses (n=43) working in a university hospital (95% of the female workforce). Almost all respondents reported known high‐risk occupational activities. Overall prevalence of reported back disorders was 44% (acute LBP 19%, chronic LBP 17%, lumbar hernia 8%). On multinomial logistic regression analysis, scoliosis and commonly stress‐related psychosomatic symptoms were associated with all three types of back disorder; trauma/ fractures of the spine, pelvis and/or legs and a global work‐environment/job‐satisfaction score with acute LBP; increasing age with lumbar disc hernia. While confirming the relevance of considering different definitions of back disorder, our data indicate items for investigation in cohort studies. These include: identification of specific risk factors for lumbar hernia; avoidance of possible work‐environment risk factors such as hurried execution of different tasks at the same time; and influence on job suitability of underlying spinal pathologies such as scoliosis.

The background of mitochondrial DNA haplogroup J increases the sensitivity of Leber's hereditary optic neuropathy cells to 2,5-hexanedione toxicity.

Lebers hereditary optic neuropathy (LHON) is a maternally inherited blinding disease due to mitochondrial DNA (mtDNA) point mutations in complex I subunit genes, whose incomplete penetrance has been attributed to both genetic and environmental factors. Indeed, the mtDNA background defined as haplogroup J is known to increase the penetrance of the 11778/ND4 and 14484/ND6 mutations. Recently it was also documented that the professional exposure to n-hexane might act as an exogenous trigger for LHON. Therefore, we here investigate the effect of the n-hexane neurotoxic metabolite 2,5-hexanedione (2,5-HD) on cell viability and mitochondrial function of different cell models (cybrids and fibroblasts) carrying the LHON mutations on different mtDNA haplogroups. The viability of control and LHON cybrids and fibroblasts, whose mtDNAs were completely sequenced, was assessed using the MTT assay. Mitochondrial ATP synthesis rate driven by complex I substrates was determined with the luciferine/luciferase method. Incubation with 2,5-HD caused the maximal loss of viability in control and LHON cells. The toxic effect of this compound was similar in control cells irrespective of the mtDNA background. On the contrary, sensitivity to 2,5-HD induced cell death was greatly increased in LHON cells carrying the 11778/ND4 or the 14484/ND6 mutation on haplogroup J, whereas the 11778/ND4 mutation in association with haplogroups U and H significantly improved cell survival. The 11778/ND4 mutation on haplogroup U was also more resistant to inhibition of complex I dependent ATP synthesis by 2,5-HD. In conclusion, this study shows that mtDNA haplogroups modulate the response of LHON cells to 2,5-HD. In particular, haplogroup J makes cells more sensitive to its toxic effect. This is the first evidence that an mtDNA background plays a role by interacting with an environmental factor and that 2,5-HD may be a risk element for visual loss in LHON. This proof of principle has broad implications for other neurodegenerative disorders such as Parkinsons disease.

Carpal tunnel syndrome and manual work: a longitudinal study.

Objective: To assess risks associated with work-related biomechanical overloads in onset/course of carpal tunnel syndrome. Methods: Workgroups with job tasks spanning different biomechanical exposures were evaluated at baseline in terms of American Conference of Governmental Industrial Hygienists hand-activity/peak force action limit and threshold limit values (TLV). Exposures of interest were “unacceptable” (hand-activity above TLV) and “borderline” (between action limit and TLV) overloads. Clinical/individual data were collected at baseline and 12 months. Results: One-year incidence of “classic/possible” carpal tunnel syndrome symptoms as defined by consensus criteria was 7.3% (153 of 2092). “Unacceptable” overload was associated with a 3-fold increased risk of onset with respect to “acceptable” load. At ordered logistic regression analysis of symptom-status variations, increased risks were recorded for “unacceptable” and “borderline” overloads. Conclusions: Effectiveness of encouraging workplace adherence to the American Conference of Governmental Industrial Hygienists recommendations deserves investigation as a possible key to wide-scale prevention.

Evaluation of Two Preventive Interventions for Reducing Musculoskeletal Complaints in Operators of Video Display Terminals

Background and Purpose The purpose of this study was to evaluate the efficacy of a preventive ergonomic intervention, which was provided by physical therapists, on spinal and upper-extremity work-related posture and symptom complaints of workers who use video display terminals (VDT). Subjects Two hundred employees who spent at least 20 hours per week at a VDT were randomly divided into 2 groups. Group E received the ergonomic intervention and an informative brochure, and group I received only the brochure. Methods Both groups were evaluated at the beginning of the study and at a follow-up 5 months later. The following tools were used: a pain drawing and the Rapid Entire Body Assessment (REBA) method to assess spinal and upper-extremity work-related posture. Results Group E had a lower REBA score and reduced lower back, neck, and shoulder symptoms compared with group I. Discussion and Conclusion The results suggest that a personalized preventive ergonomic intervention can improve spinal and upper-extremity work-related posture and musculoskeletal symptoms for workers who use VDTs.

Available instruments for measurement of psychosocial factors in the work environment

ObjectiveTo provide an overview of the spectrum of available for measurement and evaluation of work-related psychosocial factors.MethodsWe systematically searched the literature/internet to identify and describe the main available questionnaires and observational instruments for assessment of work-related psychosocial factors (with/without other job stressors).ResultsA total of 33 instruments were identified (26 questionnaires, 7 observational), many (11 questionnaires, 5 observational) linked to national institutions/intiatives. Accessibility of relevant information (on the internet or elsewhere) regarding the instruments varied widely.ConclusionsThis summary of the range of instruments currently available for evaluation of multiple work stressors at individual, group and/or organizational levels may provide a useful tool for operators and researchers.

Validation of the ACGIH TLV for hand activity level in the OCTOPUS cohort: a two-year longitudinal study of carpal tunnel syndrome

OBJECTIVES This study aimed to evaluate the risk of musculoskeletal disorders to the hand-wrist system. The American Conference of Governmental Industrial Hygienists (ACGIH) proposed threshold limit values (TLV©) based on hand activity level (HAL) and normalized peak force (PF). We validated ACGIH TLV© in OCTOPUS, a large cohort study on carpal tunnel syndrome (CTS). METHODS Industrial and service workers were followed from 2000-2003. We classified subjects with respect to action limit (AL) and TLV. Case definitions were: (i) self-reported symptoms; and (ii) combination of symptoms and positive nerve conduction studies. Poisson regression models including age, gender, body mass index, and presence of predisposing pathologies were conducted to estimate incidence rate ratios (IRR) of CTS. RESULTS There were 4097 eligible workers. Of these, 236 (5.8%) were non-responders, 2194 (53.6%) had a complete follow-up, 728 (17.8%) were lost after intermediate assessment, and 939 (22.9%) were lost after baseline. Among the 3860 subjects with complete information at baseline, 2599 (67.3%) were women [mean age 38.1 [standard deviation (SD) 9.5] years; mean body mass index (BMI) 23.8 (SD 3.9) kg/m2]. ACGIH TLV© classification predicted both CTS symptoms [IRR between AL and TLV 2.43 [95% confidence interval (95% CI) 1.77-3.33]; above TLV 3.32 (95% CI 2.34-4.72)] and CTS confirmed by nerve conduction studies [IRR between AL and TLV 1.95 (95% CI 1.21-3.16); above TLV 2.70 (95% CI 1.48-4.91)]. CONCLUSIONS We found a dose-response relationship between ACGIH TLV© classification and risk of CTS. The increased risk observed for workers exposed between AL and TLV suggests that the current AL and TLV might not be sufficiently protective.

Effectiveness of an ergonomic intervention on work-related posture and low back pain in video display terminal operators: A 3 year cross-over trial

UNLABELLED This study investigated the effectiveness of a workstation ergonomic intervention for work-related posture and low back pain (LBP) in Video Display Terminal (VDT) workers. 100 VDT workers were selected to receive the ergonomic intervention, whereas 100 were assigned to a control group. The two groups were then crossed-over after 30 months from baseline. Follow-ups were repeated at 5, 12, and 30 months from baseline and then at 6 months following crossover. OUTCOMES Work-related posture and LBP point-prevalence using the Rapid Entire Body Assessment method and a Pain Drawing, respectively. The ergonomic intervention at the workstation improved work-related posture and was effective in reducing LBP point-prevalence both in the first study period and after crossover, and these effects persisted for at least 30 months. In conclusion, our findings contribute to the evidence that individualized ergonomic interventions may be able to improve work-related posture and reduce LBP for VDT workers.

Musculoskeletal pain in Europe: the role of personal, occupational, and social risk factors

OBJECTIVES The prevalence of musculoskeletal pain in European countries varies considerably. We analyzed data from the fifth European Working Conditions Survey (EWCS) to explore the role of personal, occupational, and social risk factors in determining the national prevalence of musculoskeletal pain. METHODS Over the course of 2010, 43 816 subjects from 34 countries were interviewed. We analyzed the one-year prevalence of back and neck/upper-limb pain. Individual-level risk factors studied included: sex; age; educational level; socioeconomic status; housework or cooking; gardening and repairs; somatizing tendency; job demand-control; six physical occupational exposures; and occupational group. Data on national socioeconomic variables were obtained from Eurostat and were available for 28 countries. We fitted Poisson regression models with random intercept by country. RESULTS The main analysis comprised 35 550 workers. Among individual-level risk factors, somatizing tendency was the strongest predictor of the symptoms. Major differences were observed by country with back pain more than twice as common in Portugal (63.8%) than Ireland (25.7%), and prevalence rates of neck/upper-limb pain ranging from 26.6% in Ireland to 67.7% in Finland. Adjustment for individual-level risk factors slightly reduced the large variation in prevalence between countries. For back pain, the rates were more homogenous after adjustment for national socioeconomic variables. CONCLUSIONS Our analysis indicates substantial variation between European countries in the prevalence of back and neck/upper-limb pain. This variation is unexplained by established individual risk factors. It may be attributable in part to socioeconomic differences between countries, with higher prevalence where there is less risk of poverty or social exclusion.

Grand Rounds: Could Occupational Exposure to n-Hexane and Other Solvents Precipitate Visual Failure in Leber Hereditary Optic Neuropathy?

Context Leber hereditary optic neuropathy (LHON) is a maternally inherited loss of central vision related to pathogenic mutations in the mitochondrial genome, which are a necessary but not sufficient condition to develop the disease. Investigation of precipitating environmental/occupational (and additional genetic) factors could be relevant for prevention. Case presentation After a 6-month period of occupational exposure to n-hexane and other organic solvents, a 27-year-old man (a moderate smoker) developed an optic neuropathy. The patient had a full ophthalmologic and neurologic investigation, including standardized cycloergometer test for serum lactic acid levels and a skeletal muscle biopsy. His exposure history was also detailed, and he underwent genetic testing for LHON mitochondrial DNA mutations. The patient suffered a sequential optic neuropathy with the hallmarks of LHON and tested positive for the homoplasmic 11778G → A/ND4 mutation. Routine laboratory monitoring revealed increased concentrations of urinary 2.5 hexandione (n-hexane metabolite) and hippuric acid (toluene metabolite) in the period immediately preceding the visual loss. Discussion In a subject carrying an LHON mutation, the strict temporal sequence of prolonged appreciable occupational exposure followed by sudden onset of visual loss must raise a suspicion of causality (with a possible further interaction with tobacco smoke). Relevance In this article, we add to the candidate occupational/environmental triggers of LHON and highlight the need for appropriate case–control (and laboratory) studies to validate the causal effect of mixed toxic exposures.

Biomarkers to assess the genetic damage induced by alcohol abuse in human lymphocytes

Alcohol abuse is a major risk factor for cancer of the upper alimentary tract, the upper respiratory tract, and liver. Chromosome damage is used as early effect biomarker in the surveillance of human exposure to genotoxic carcinogens. In the present study, two genetic markers, namely chromosome aberrations (CAs) and micronuclei (MN), were used to evaluate genetic damage in peripheral lymphocytes from 20 alcoholics, 20 abstinent alcoholics, and 20 controls. Composition of the three groups was fairly similar as regards sex, age and smoking habits. A highly significant increase was observed in the frequencies of CA and MN in lymphocytes of alcoholics as compared both with controls and abstinent alcoholics. However, no correlation was found between the length of alcohol abuse and the frequencies of either biomarkers in alcoholics. CA and MN frequencies in abstinent alcoholics were similar than those in controls. Our data indicate that CA and MN can be two useful biomarkers to assess genetic damage associated with alcohol abuse. They could be included in programs for cancer prevention in alcoholics. Abstinence appears to normalize the frequency of both MN and CA. This could offer therapists another tool to help alcoholics change their lifestyle.