SJWEH - Online-first articles

Does a history of physical exposures at work affect hand-grip strength in midlife? A retrospective cohort study in Denmark

Fri, 10 May 2013 20:27:09 +0200

Objective The aim of this cohort study was to examine associations between physical exposures throughout working life and hand-grip strength (HGS) in midlife. Methods The Copenhagen Aging and Midlife Biobank (CAMB) provided data about employment and HGS for 3843 Danes. Individual job histories, including duration of employment in specific jobs, were assigned exposures from a job exposure matrix. Exposures were standardized to ton-years (lifting 1000 kg each day in one year), stand-years (standing/walking for six hours each day in one year) and kneel-years (kneeling for one hour each day in one year). The effects of exposure-years on HGS were analyzed as linear effects and cubic splines in multivariate regression models, adjusted for potential confounders. Results Mean age was 59 years among both genders and HGS was 49.19 kg [standard deviation (SD) 8.42] and 30.61 kg (SD 5.49) among men and women, respectively. Among men, exposure to kneel-years was associated with higher HGS (>0.030 kg (P=0.007) per exposure-year). Ton- and stand-years were not associated with HGS among either men or women in linear analyses. In spline regression analyses, associations between ton- and stand-years and HGS were non-linear and primarily positive among men. Among women, the associations were non-linear and, according to ton-years, primarily negatively associated with HGS but statistically insignificant. Conclusion A history of physical exposures at work explained only a minor part of the variation in HGS, though exposure to kneeling throughout working life was associated with a slightly higher HGS among men. Exposure to lifting and standing/walking was not associated with HGS. by M�ller A, Reventlow S, Hansen �M, Andersen LL, Siersma V, Lund R, Avlund K, Andersen JH, Mortensen OS. doi:10.5271/sjweh.3366

Change in economic difficulties and physical and mental functioning: Evidence from British and Finnish employee cohorts

Mon, 22 Apr 2013 16:50:05 +0200

Objective The main aims of this longitudinal study were to (i) examine associations between changes in economic difficulties and health functioning among middle-aged employees and (ii) assess whether the associations remained after considering conventional domains of socioeconomic position. The associations were tested in two European welfare state occupational cohorts to strengthen the evidence base and improve generalizability. Methods Data came from two cohorts: the Finnish Helsinki Health Study (baseline 2000�2002, follow-up 2007, N=6328) and the British Whitehall II Study (baseline 1997�1999, follow-up 2003�2004, N=4350). Responses to the survey item �finding it hard to afford adequate food and clothes and pay bills� repeated at baseline and follow-up were used to examine persistent, increasing, and decreasing economic difficulties. Poor physical and mental health functioning were denoted as being in the lowest quartile of the Short Form 36 physical and mental component summary. Logistic regression analyses were adjusted for sex, age, childhood economic difficulties, household income at baseline and follow-up, employment status at follow-up, and baseline health functioning. Results We observed strong sex- and age-adjusted associations between increasing [odds ratio (OR) range 1.69�2.96] and persistent (OR range 2.54�3.21) economic difficulties and poorer physical and mental health functioning in both British and Finnish occupational cohorts. These associations remained after full adjustments. Those reporting decreasing difficulties over follow-up also had poorer functioning (OR range 1.30�1.61) compared to those who did not have difficulties at baseline, possibly reflecting residual effects of economic difficulties at baseline. Conclusion Changes in economic difficulties are associated with poorer physical and mental health functioning independent of income, employment status, and baseline health functioning by Lallukka T, Ferrie JE, Rahkonen O, Shipley MJ, Pietil�inen O, Kivim�ki M, Marmot MG, Lahelma E. doi:10.5271/sjweh.3365

Risk and rate advancement periods of total hip replacement due to primary osteoarthritis in relation to cumulative physical workload

Wed, 17 Apr 2013 17:27:15 +0200

Objectives This study aims to (i) evaluate relative risks, excess fraction of cases, and rate advancement periods for total hip replacement (THR) due to primary osteoarthritis in relation to lifelong cumulative physical workload and (2) describe temporal trends in the proportion employed in the most highly exposed industries from 1986�2006. Methods In a cohort study of the Danish working population, we assessed cumulative physical workload by combining year-by-year register information on employment industry with an industry exposure matrix that provided point scores (0�2) of physical workload. Cumulative physical workload was expressed as point-years corresponding to the pack-year concept of smoking. We retrieved register information on first-time THR during 1996�2006 and used a logistic regression technique to fit discrete time hazards models adjusting for age and other factors. We calculated excess fraction of cases and rate advancement periods. Results Total numbers of point-years ranged from 0�86. For men, an exposure�response relation was observed reaching an odds ratio of 1.33 [95% confidence interval (95% CI) 1.17�1.53] for the highest exposure category (35�86 point-years) compared to 0 point-years. The excess fraction of cases was 18%, and THR took place up to 3.4 years earlier with increasing exposure. For women, no exposure�response relation was found. Conclusions At the population level, cumulative physical workload increased the risk of THR among men, with surgery being performed slightly earlier in life. The proportion employed in the most highly exposed industries remained constant. by Rubak TS, Svendsen SW, S�balle K, Frost P. doi:10.5271/sjweh.3361

The effectiveness of a construction worksite prevention program on work ability, health, and sick leave: results from a cluster randomized controlled trial

Mon, 08 Apr 2013 18:43:25 +0200

Objective This study aimed to investigate the effectiveness of a prevention program on work ability, health, and sick leave targeted at construction worksites. Methods A total of 15 departments (N=297 workers) from 6 construction companies participated in this cluster randomized controlled trial and were randomly allocated to the intervention (8 departments; N=171 workers) or control (7 departments; N=122 workers) group. The intervention consisted of two individual training sessions with a physical therapist aimed at lowering the physical workload, a rest-break tool to improve the balance between work and recovery, and two empowerment training sessions to increase the worker�s influence at the worksite. Data on work ability, physical and mental health status, and musculoskeletal symptoms were collected at baseline, and at 3, 6, and 12 months follow-up. Sick leave data were obtained from the companies. Results Overall, no differences in work ability [β 0.02, 95% confidence interval (95% CI) -0.34�0.37] or physical and mental health status (β -0.04, 95% CI -1.43�1.35, and β 0.80 95% CI -1.43�1.35, respectively) were found between the intervention and control group. The intervention showed an overall decline in musculoskeletal symptoms (ranging from OR 0.68, 95% CI 0.34�1.33, to OR 0.86, 95% CI 0.47�1.57) and long-term sick leave (OR 0.44, 95% CI -0.34�0.37) among construction workers. Both reductions were not statistically significant. Conclusion The prevention program seemed to result in a beneficial but not statistically significant decline in the prevalence of musculoskeletal symptoms and long-term sick leave among construction workers, but showed no effects with regard to work ability, physical health, and mental health. by Oude Hengel KM, Blatter BM, van der Molen HF, Bongers PM, van der Beek AJ. doi:10.5271/sjweh.3360

Night work and breast cancer estrogen receptor status � results from the German GENICA study

Fri, 29 Mar 2013 16:05:58 +0200

Objectives The potential mechanisms that link night-shift work with breast cancer have been extensively discussed. Exposure to light at night (LAN) depletes melatonin that has oncostatic and anti-estrogenic properties and may lead to a modified expression of estrogen receptor (ER) α. Here, we explored the association between shift work and breast cancer in subgroups of patients with ER-positive and -negative tumors. Methods GENICA (Gene�ENvironment Interaction and breast CAncer) is a population-based case�control study on breast cancer with detailed information on shift work from 857 breast cancer cases and 892 controls. ER status was assessed by immunohistochemical staining. Associations between night-shift work and ER-positive and -negative breast cancer were analyzed with conditional logistic regression models, adjusted for potential confounders. Results ER status was assessed for 827 cases and was positive in 653 and negative in 174 breast tumors. Overall, 49 cases and 54 controls were �ever employed� in shift work including night shifts for ≥1 year. In total, �ever shift work� and �ever night work� were not associated with an elevated risk of ER-positive or -negative breast tumors. Night work for ≥20 years was associated with a significantly elevated risk of ER-negative breast cancer [odds ratio (OR) 4.73, 95% confidence interval (95% CI) 1.22�18.36]. Conclusions Our case�control study suggests that long-term night-shift work is associated with an increased risk of ER-negative breast cancers. Further studies on histological subtypes and the analysis of other potentially relevant factors are crucial for discovering putative mechanisms by Rabstein S, Harth V, Pesch B, Pallapies D, Lotz A, Justenhoven C, Baisch C, Schiffermann M, Haas S, Fischer H-P, Heinze E, Pierl C, Brauch H, Hamann U, Ko Y, Br�ning T. doi:10.5271/sjweh.3359

Work-related psychosocial and mechanical risk factors for work disability: a 3-year follow-up study of the general working population in Norway

Mon, 25 Mar 2013 16:52:14 +0200

Objectives This study examines the impact of work-related psychosocial and mechanical risk factors for work disability in the general working population. Methods A randomly drawn cohort from the general population in Norway aged 18�66 years was followed for 3 years (N=12 550, 67% response rate at baseline). Eligible respondents were in paid work for ≥10 hours per week in 2006 and were still in paid work or had quit working because of health problems (work disability) in 2009 (N=6745). Five work-related psychosocial factors and eight mechanical exposures were measured. The outcome of interest was self-reported work disability at 3-year follow-up. Results In total, 2.6% (176 individuals) reported work disability at the 3-year follow-up. Disability rates were higher among women, older workers, and those with fewer years of education and higher levels of psychological distress and musculoskeletal complaints. After adjusting for these factors, work-related psychosocial predictors of disability were low levels of supportive leadership [odds ratio (OR) 1.61, 95% confidence interval (95% CI) 1.02�2.56] and monotonous work (OR 1.53, 95% CI 1.09�2.16). Mechanical factors were neck flexion (OR 2.49, 95% CI 1.36�4.56), prolonged standing (OR 1.79, 95% CI 1.21�2.46), whole-body vibration (OR 4.15, 95% CI 1.77�9.71), and heavy physical work (OR 2.23. 95% CI 1.08�4.57). The estimated population risk attributable to these factors was about 45%. Conclusion Monotonous work, prolonged standing, neck flexion, and whole-body vibration appear to be the most consistent and important predictors of work disability. by Sterud T. doi:10.5271/sjweh.3358

Chromosomal damage among medical staff occupationally exposed to volatile anesthetics, antineoplastic drugs, and formaldehyde

Fri, 22 Mar 2013 23:46:37 +0200

Objectives Structural chromosomal aberrations in blood lymphocytes represent a biomarker for cellular damage caused by genotoxic carcinogens and are an indicator of increased cancer risk. We evaluated the association between frequencies of total chromosomal aberrations, chromatid- and chromosome-type aberrations, and occupational exposures to volatile anesthetics, antineoplastic agents, and formaldehyde among 601 medical professionals. Methods Chromosomal damage among exposed individuals and unexposed controls was determined by conventional cytogenetic analysis. We used binary logistic regression to evaluate the effects of workplace exposures and major confounders on chromosomal damage. Results Significantly higher frequencies of total chromosomal, chromatid-type and chromosome-type aberrations were observed among subjects occupationally exposed to volatile anesthetics, antineoplastic agents, and formaldehyde compared to age- and sex-matched controls (P<0.0001). The risk of an increased frequency of chromosomal aberrations was associated with exposure to anesthetics [odds ratio (OR) 3.9, 95% confidence interval (95% CI) 2.7�5.8], cytostatics (OR 2.7, 95% CI 1.9�3.9), and formaldehyde (OR 1.7, 95% CI 1.1�2.7). No other covariate contributed significantly to the model. Chromatid- and chromosome-type aberrations were associated with exposure to anesthetics and cytostatics without any contribution of other variables. Stratified data analysis showed the risk of increased chromosomal aberrations among non-smoking female nurses and physicians exposed to anesthetics, cytostatics and, partially, formaldehyde. Chromatid and chromosome exchanges were significantly higher in the exposed groups than among controls. Conclusion Our findings indicate that the presence of genotoxic compounds in operating rooms, oncological units, and pathological departments results in a significant increase of chromosomal damage (impair of chromosomal integrity) among medical workers employed in these facilities. by Musak L, Smerhovsky Z, Halasova E, Osina O, Letkova L, Vodickova L, Polakova V, Buchancova J, Hemminki K, Vodicka P. doi:10.5271/sjweh.3357

The effect of work-related sustained trapezius muscle activity on the development of neck and shoulder pain among young adults

Thu, 14 Mar 2013 18:58:18 +0200

Objective This study aimed to evaluate if sustained trapezius muscle activity predicts neck and shoulder pain over a 2.5-year period. Methods Forty young adults (15 hairdressers, 14 electricians, 5 students and 6 with various work) were followed during their first years of working life. Self-reported neck and shoulder pain during the last four weeks was assessed seven times over the observational period. Upper-trapezius muscle activity was measured during a full working day by bilateral surface electromyography (EMG) at baseline (winter 2006/7). Sustained trapezius muscle activity was defined as continuous muscle activity with amplitude >0.5% EMGmax lasting >4 minutes. The relative time of sustained muscle activity during the working day was calculated and further classified into low (0�29%), moderate (30�49%) and high (50�100%) level groups. Results Generalized estimating equations (GEE), adjusted for time, gender, mechanical workload, control-over-work intensity, physical activity, tobacco use, and prior neck and shoulder pain, showed that participants with a high level of sustained muscle activity had a rate of neck and shoulder pain three times higher than the low level group during a 2.5-year period. The association was strongest at the same time and shortly after the EMG measurement, indicating a time-lag of ≤6 months. Conclusion The results support the hypothesis that sustained trapezius muscle activity is associated with neck and shoulder pain. This association was strongest analyzing cross-sectional and short-term effects. by Hanvold TN, W�rsted M, Mengshoel AM, Bjertness E, Stigum H, Twisk J, Veiersted KB. doi:10.5271/sjweh.3356

Working hours and depressive symptomatology among full-time employees: Results from the fourth Korean National Health and Nutrition Examination Survey (2007�2009)

Thu, 14 Mar 2013 18:13:57 +0200

Objective This study aimed to examine the distribution of working hours and the association between working hours and depressive symptomatology using representative data from a national, population-based survey. Method Data came from the fourth Korean National Health and Nutrition Examination Survey (2007�2009), which employed a systematic, stratified cluster-sampling method. We used logistic regression procedures to estimate the importance of weekly working hours as a predictor of depressive symptomatology. Results The prevalence of depressive symptomatology was 10.2%. The work week, which averaged 48.3 hours for the sample as a whole, was longer for men (49.8 hours) than women (45.3 hours), and 12.1% of respondents were engaged in shift work. In logistic regression analyses, compared to those working <52 hours per week, the odds ratios (OR) of working hours as a predictor of depressive symptomatology were 1.19 [95% confidence interval (95% CI) 0.77�1.85] for those working 52�59 hours per week and 1.62 (95% CI 1.20�2.18) for those working ≥60 hours per week, after adjustment for demographic characteristics, health behaviors, socioeconomic status, employment status, and work schedules. It showed a positive dose�response relationship between working hours and depressive symptomatology (P=0.0059). Conclusions Working hours in Korea are long. There is an association between working hours and depressive symptomatology, and there seems be a trend in working hours and depressive symptomatology. by Kim I, Kim H, Lim S, Lee M, Bahk J, June KJ, Kim S, Chang WJ. doi:10.5271/sjweh.3355

Black boxes and modifiable exposures

Wed, 06 Mar 2013 16:58:48 +0200

by Olsen J. doi:10.5271/sjweh.3353

Do work factors modify the association between chronic health problems and sickness absence among older employees?

Mon, 25 Feb 2013 17:12:09 +0200

Objectives The aim of this study was to (i) assess how common chronic health problems and work-related factors predict sickness absence and (ii) explore whether work-related factors modify the effects of health problems on sickness absence. Methods A one-year longitudinal study was conducted among employed persons aged 45�64 years from the Study on Transitions in Employment, Ability and Motivation (N=8984). The presence of common chronic health problems and work-related factors was determined at baseline and self-reported sickness absence at one-year follow-up by questionnaire. Multinomial multivariate logistic regression analyses were conducted to assess associations between health, work factors, and sickness absence, and relative excess risk due to interaction (RERI) techniques were used to test effect modification. Results Common health problems were related to follow-up sickness absence, most strongly to high cumulative sickness absence (>9 days per year). Baseline psychological health problems were strongly related to high sickness absence at follow-up [odds ratio (OR) 3.67, 95% confidence interval (95% CI) 2.80�4.82]. Higher job demands at baseline increased the likelihood of high sickness absence at follow-up among workers with severe headaches [RERI 1.35 (95% CI 0.45�2.25)] and psychological health problems [RERI 3.51 (95% CI 0.67�6.34)] at baseline. Lower autonomy at baseline increased the likelihood of high sickness absence at follow-up among those with musculoskeletal [RERI 0.57 (95% CI 0.05�1.08)], circulatory [RERI 0.82 (95% CI 0.00�1.63)], and psychological health problems [RERI 2.94 (95% CI 0.17�5.70)] at baseline. Conclusions Lower autonomy and higher job demands increased the association of an array of common chronic health problems with sickness absence, and thus focus should be placed on altering these factors in order to reduce sickness absence and essentially promote sustainable employability. by Leijten FRM, van den Heuvel SG, Ybema JF, Robroek SJW, Burdorf A. doi:10.5271/sjweh.3352

Prognosis of ulnar neuropathy and ulnar neuropathy-like symptoms in relation to occupational biomechanical exposures and lifestyle

Thu, 21 Feb 2013 19:43:03 +0200

Objective The aim of this paper was to identify prognostic factors for severity of symptoms and disability among patients with ulnar neuropathy confirmed by nerve conduction studies (NCS) or ulnar neuropathy-like symptoms with normal ulnar nerve NCS. Methods We conducted a cohort study based on a matched case-referent study. In 2008, we mailed a questionnaire to 1179 patients who were examined by NCS for suspected ulnar neuropathy at the age of ≥18�<65 years, 2001�2007. Potential prognostic factors included occupational biomechanical exposures, lifestyle factors, and NCS result. Outcomes were severity of symptoms and disability according to questionnaire scores. Referents delivered reference values. We used ordinal logistic regression. Results The percentage of those responding was 61%, comprising 324 patients with ulnar neuropathy and 396 with ulnar neuropathy-like symptoms. At follow-up, both patient groups had more severe symptoms and disability than age and sex matched referents. Abnormal NCS indicated a poorer prognosis regarding symptom severity [odds ratio (OR) 1.44, 95% confidence interval (95% CI) 1.01�2.01], but not disability (OR 0.78, 95% CI 0.57�1.08). High occupational force requirements indicated a poorer prognosis regarding both symptom severity (OR 1.78, 95% CI 1.10�2.88) and disability (OR 1.66, 95% CI 1.06�2.59). Other negative prognostic factors for both outcomes were current smoking, obesity, distal upper-extremity fractures, female sex, and a recent NCS date (suggesting improvement over time). Conclusions NCS confirmation of ulnar neuropathy identified patients with a poorer prognosis regarding symptoms. A negative impact of high occupational force requirements, current smoking, and obesity on both outcomes suggested that reduction of these factors might improve prognosis of ulnar neuropathy and ulnar neuropathy-like symptoms. by Svendsen SW, Johnsen B, Fuglsang-Frederiksen A, Frost P. doi:10.5271/sjweh.3351

Prevalence and incidence of carpal tunnel syndrome in US working populations: pooled analysis of six prospective studies

Tue, 19 Feb 2013 21:28:33 +0200

Objectives Most studies of carpal tunnel syndrome (CTS) incidence and prevalence among workers have been limited by small sample sizes or restricted to a small subset of jobs. We established a common CTS case definition and then pooled CTS prevalence and incidence data across six prospective studies of musculoskeletal outcomes to measure CTS frequency and allow better studies of etiology. Methods Six research groups collected prospective data at >50 workplaces including symptoms characteristic of CTS and electrodiagnostic studies (EDS) of the median and ulnar nerves across the dominant wrist. While study designs and the timing of data collection varied across groups, we were able to create a common CTS case definition incorporating both symptoms and EDS results from data that were collected in all studies. Results At the time of enrollment, 7.8% of 4321 subjects met our case definition and were considered prevalent cases of CTS. During 8833 person-years of follow-up, an additional 204 subjects met the CTS case definition for an overall incidence rate of 2.3 CTS cases per 100 person-years. Conclusions Both prevalent and incident CTS were common in data pooled across multiple studies and sites. The large number of incident cases in this prospective study provides adequate power for future exposure�response analyses to identify work and non-work related risk factors for CTS. The prospective nature allows determination of the temporal relations necessary for causal inference. by Dale AM, Harris-Adamson C, Rempel D, Gerr F, Hegmann K, Silverstein B, Burt S, Garg A, Kapellusch J, Merlino L, Thiese MS, Eisen EA, Evanoff B. doi:10.5271/sjweh.3350

Notification of occupational disease and risk of work disability � authors� response to commentaries

Tue, 19 Feb 2013 20:36:55 +0200

Poul Frost and colleagues (1) argue that the excess work disability that we observed following notification of occupational disease is small and reassuring indicating no need for major concern. We agree with respect to patients who are not at work when notified because for them we observed no increased risk of subsequent work disability. For patients, who were at work when notified, we do not agree however. For them, we observed a hazard ratio of 1.46 [95% confidence interval (95% CI) 1.17�1.82] and a risk difference of 12.5% (risk notified - risk not notified = 48.1% - 35.6%) (2). Whether an absolute risk of 12.5% is small or not depends on the comparison. One example among many is Acheson and colleagues� seminal work on sinonasal adenocarcinoma in wood-dust-exposed Buckinghamshire furniture workers, a milestone in occupational epidemiology (3, 4). In a population of 5371, they observed 8 cases of sinonasal adenocarcinoma while the expected number was 0.06. This corresponds to a risk difference of 0.15% which is about 1/80 of that observed in our study. Had their findings been neglected because of arguments about low public health impact, we would have been denied information with immense impact on our understanding of carcinogenesis as well as the prevention of sinonasal cancer. Another way of assessing the size of the problem is by estimating the excess number in the general population. Annually, about 18 000 patients are notified of occupational disease in Denmark. If we assume that 50% are at work when notified, as in our data, this means that 1125 patients are work-disabled annually due to notification if our findings represent a causal effect (18 000 � 50% � 12.5%). This is in our opinion not a negligible number of patients even if it is expected to represent a small fraction of all work-disabled patients as only about 0.6% of the workforce is notified annually. A low population-attributable fraction is generally seen in occupational medicine because of low population exposure prevalence (5). The high prevalence of work disability in our study population indicates a multifactorial etiology that includes more and frequent causes than for sinonasal adenocarcinoma, but this should not inveigle us into neglecting individual risk factors that step by step may improve our understanding of the mechanisms behind work disability and furthermore may be amendable and thus targeted by preventive initiatives that can improve workers� health (6). In our opinion, the major problem is thus not the magnitude of the effect we observed but how workers� compensation systems can implement our results, bearing in mind the methodological limitations of the study and the fact that this is a delicate topic in occupational health. In a second commentary on our original research, Kuijer and colleagues (7) argue � based on Dutch experiences � that our suggestions for changing worker�s compensation might be counterproductive for preventing work disability. They refer to a national survey showing that patients who presumed that their disease was work-related and who were not notified had longer sick leave. In our opinion, this indicates that patients� perception of work-relatedness may be an important confounder when studying the effect of notification. Because all patients included in our study were referred to our occupational medicine department explicitly because their health problems were presumed to be work-related this should, however, not have confounded our results. By the same token, the side-effect of notification that we observed should add on top of the effect associated with the mere presumption of work-relatedness. Kuijer and colleagues recommend a randomized, controlled intervention study as more appropriate than our observational design. We agree that this would have addressed the key problem of higher levels of clinical, occupational, and social characteristics, which predict a poorer vocational prognosis, among the notified patients. However, this was and is not an option due to ethical and statutory reasons. Kuijer et al recommend that occupational physicians discuss the work-relatedness of the illness with their patients, make a timely diagnosis, and provide appropriate care and intervention at the workplace to prevent work disability. We fully agree, and this is the focus of our clinical as well as our scientific work (8�10) as it should be for any occupational physician regardless of whether the patient�s disease is caused by the occupation or not, or whether the patient is notified to the compensation board or not. Our data suggest that the latter may be an important predictor of work disability. Conflicts of interest Lone Donb�k Jensen and Ane Marie Thulstrup prepare specialist�s statements for the National Board of Industrial Injuries. Vivi Schl�nssen is advisor for the labor union �HK Danmark� in notification issues. Jens Peter Bonde prepares expert testimonies concerning industrial injuries for the Medico-Legal Council. by Kolstad HA, Christensen MV, Jensen LD, Schl�nssen V, Thulstrup AM, Bonde JP. doi:10.5271/sjweh.3349

Avoid yelling �stop thief!� and work disability prevention due to an occupational disease

Tue, 19 Feb 2013 19:46:28 +0200

Kolstad and colleagues (1) reported on a well-conducted prospective cohort study among 2304 patients referred to an occupational medicine department of a university hospital in Denmark to assess whether the notification of an occupational disease increases the risk of work disability. Working employees with a notification had an increased risk of work disability with a hazard ratio of 1.4 [see table 2 (1]). Their recommendation is that �compensation systems should ensure that only workers with high odds of compensation are notified and physicians should consider the risk of exclusion from the job market before notifying a patient�. This is remarkably outspoken advice for such a delicate topic in occupational health. We believe this recommendation might be one step ahead of their findings and, more importantly, might be counterproductive for the prevention of work disability. First, regarding the evidence base, the notified group differs considerably from the non-notified group at baseline regarding prognostic factors for work disability: for instance there are more blue-collar workers (76% versus 54%), ergonomic exposures (51% versus 26%) and work-related disabling diseases such as dorsalgia (14% versus 7%), shoulder lesions (10% versus 4%), irritant contact dermatitis (8% versus 2%), Raynaud�s syndrome (5% versus 1%), and carpal tunnel syndrome (5% versus 1%). In addition, no adjustments were made for physical and mental job demands. The authors are aware of this given their statement in the conclusion �� data analyses may not have fully accounted for the poorer vocational prognosis��. Moreover, work disability was in fact defined as sick leave of >12 weeks in the upcoming year, independent of the notified occupational disease. From a national survey in the Netherlands, we know that among working patients, who presume that their disease is mainly or partly work-related and who were not notified, the duration of sick leave is more than twice as long when taking into account the type of disease: 16 versus 7 days (2). A similar effect was found among Dutch patients without employment who were not notified about their occupational disease: the sickness absence lasted 1.5 times longer when the sick-listing was due to an occupational disease, and 2.6 times more often the sick-listed worker reached � after two years of sick leave � the work disability assessment required for the entitlement of disability benefits. At that time, they were granted the disability benefits twice as often. Secondly, we consider an intervention study to be more appropriate to support this kind of recommendation, preferably a (randomized) controlled study. No description is given about the potential impact of the notification: how was the patient notified about the occupational disease? At what point in time was this done since the complaints arose? How were the consequences for return-to-work discussed and what care was provided to support sustainable return-to-work among this vulnerable population? Especially in the case of an occupational disease, timely and tailored integrated care might be necessary to accomplish sustainable return-to work, with an important role for both employer and employee and of course the occupational physician (4, 5). Finally, by the nature of their job, occupational physicians should discuss as soon as possible the work-related aspects of a disease with their patient, regardless of the compensation mechanisms at stake. Many patients themselves have � true or false � perceptions and expectations about the work-relatedness of their complaints. In the Netherlands, more than 50% of the employees on sick leave due to mental health complaints and musculoskeletal complaints of the low back and upper extremity are of the opinion that work is mainly or partly the cause (2). Therefore, instead of a recommendation that might discourage occupational physicians from discussing the work-relatedness of the disease with their patients, a timely diagnosis and appropriate care and intervention at the workplace seems warranted to prevent work disability in the case of an occupational disease (6). We do not expect a security officer to remain silent while witnessing a theft; the same goes for an occupational physician unwilling to address the topic and consequences of an occupational disease. by Kuijer PPFM, Smits PB, van der Molen HF, van Dijk FJH. doi:10.5271/sjweh.3348

Notification of occupational disease and risk of work disability � how concerned should we be?

Tue, 19 Feb 2013 19:32:15 +0200

We have with interest read the article by Kolstad et al (1) on the risk of work disability in relation to notification of occupational disease. The study comprised patients seen at a Danish department of occupational medicine and used routinely collected registrations and historical register information on social benefits. Work disability was defined as a year with >12 weeks of sick payment, unemployment payment, disability pension, rehabilitation benefit, or other social benefits. Overall, the hazard ratio (HR) of work disability was 1.11 [95% confidence interval (95% CI) 0.99�1.27] within two years. In the subgroup who were not working at baseline, a HR of 0.99 (95% CI 0.85�1.15) was found. However, a HR of 1.46 (95% CI 1.17�1.82) was reported in the subgroup who were working at baseline. In this group, 124 cases of work disability were identified among patients who were notified (48.1%), while the number of cases was 337 among patients not notified (35.6%). In the total cohort of 2304 patients, 1435 became work disabled (62.3%). Kolstad et al did not estimate the proportion of cases that could have been prevented if none of the patients had been notified. Since this proportion is of major importance to capture the size of the problem, we calculated the excess number of cases in the working subgroup using the HR and the observed number of cases and found that 39 cases [(1.46-1)/1.46�124 cases] were in theory in excess. Thus, the proportion of preventable cases was 8.5% [39/(124+337)�100%] of all cases appearing in the working subgroup and 2.7% [39/1435�100%] of all cases in the total cohort. In other words, completely avoiding notification would reduce the overall disability problem by less than 3%. Notified patients differed from non-notified patients with regard to several factors with a likely negative impact on their work situation. Kolstad et al were well aware of this threat to the internal validity of their results (confounding by indication). Despite this and the fact that the small excess fraction of cases clearly points to other factors as more important for work disability than notification, Kolstad et al called for administrative changes advocating that �The findings of this study underpin the need for actions that effectively reduce administrative delays �. and for changes of notification and acknowledgement procedures to ensure that only workers with high odds of compensation are notified�. Kolstad et al also advised colleagues �to consider the risk of exclusion from the job market� before making a notification�. Many medical establishments have expressed concerns that the mere claiming of workers� compensation may have a negative impact on vocational prognosis. The results presented by Kolstad et al are in fact reassuring with regard to the effect of notification on risk of work disability. Overall, the patients in the study cohort of Kolstad et al managed badly on the labor market, notification or not. Prevention of work disability among working-aged patients in secondary healthcare is certainly an important issue, but given the results presented by Kolstad et al there is no need for major concerns for negative side effects of notification of occupational disease. by Frost P, Andersen JH, Thomsen JF, Svendsen SW. doi:10.5271/sjweh.3346

The effect of overcommitment and reward on muscle activity, posture, and forces in the arm-wrist-hand region � a field study among computer workers

Fri, 01 Feb 2013 16:43:22 +0200

Objective Office workers with high levels of overcommitment and low levels of reward are thought to be more prone to arm-wrist-hand symptoms, possibly through a higher internal physical exposure. The aim of this study was to examine the effects of high overcommitment and low reward on (i) forearm muscle activity, (ii) wrist posture and kinematics, and (iii) forces applied to computer input devices during computer work in an actual work setting. Methods We continuously measured wrist extensor muscle activity, wrist posture and kinematics, and forces applied to the keyboard and mouse for two hours during the daily work of 120 office workers with four different levels of overcommitment and reward (low�high, high�high, low�low, and high�low). Results Wrist velocities and accelerations in radial-ulnar direction were higher for workers with high compared to low overcommitment, while their wrist range of motion was similar, possibly indicating a higher work pace. Wrist extensor muscle activity and forces applied to the keyboard and mouse were not increased by high overcommitment and/or low reward. Conclusion Overall, our findings provide little support for the proposed pathway of high overcommitment and low reward in the development of arm-wrist-hand symptoms through a higher internal physical exposure. by Eijckelhof BHW, Bruno Garza JL, Huysmans MA, Blatter BM, Johnson PW, van Die�n JH, van der Beek AJ, Dennerlein JT. doi:10.5271/sjweh.3345

Disability pension due to musculoskeletal diagnoses: importance of work-related factors in a prospective cohort study of Finnish twins

Mon, 28 Jan 2013 18:41:42 +0200

Objectives The aim of this study was to investigate the impact of work-related risk factors for future disability pension (DP) due to musculoskeletal diagnoses and for a subgroup of these, namely, DP due to osteoarthritis. Methods For this prospective study of 16�028 Finnish twins born in 1911�1957 and employed at baseline, a postal questionnaire collected information in 1975 on work-related factors; follow-up data on DP was gathered through register linkages up to 2004. A series of proportional hazards (Cox) regression models were used to analyze the associations between work-related factors and the incidence of DP. Results During the 30-year follow-up, 1297 participants (8%) were granted DP due to musculoskeletal diagnoses, 376 of which were due to osteoarthritis. High stress of daily activities, monotonous work, physical workload (namely work including lifting and carrying or physically heavy work), several workplace changes, and unemployment displayed a strong association with DP due to musculoskeletal diagnoses that was not affected by familial factors, including genetics and shared environment. Additionally, standing work increased the risk for DP due to osteoarthritis. Conclusions Uninfluenced by family background or other confounding factors, several work-related factors were identified as being strong and direct risk factors for DP due to musculoskeletal diagnoses. by K�rkk�inen S, Pitk�niemi J, Silventoinen K, Svedberg P, Huunan-Sepp�l� A, Koskenvuo K, Koskenvuo M, Alexanderson K, Kaprio J, Ropponen A. doi:10.5271/sjweh.3344

Assessment of the effect of occupational exposure to formaldehyde on the risk of lung cancer in two Canadian population-based case�control studies

Thu, 17 Jan 2013 21:56:41 +0200

Objective This study aimed to explore the possible association between formaldehyde exposure and lung cancer risk. Methods Data were collected in two population-based case�control studies conducted in Montreal, Canada. Cases were individuals diagnosed with incident, histologically-confirmed lung cancer. Controls were randomly selected from electoral lists and frequency-matched to cases by age, sex, and electoral district of residence. Interviews for the two studies were conducted in 1979�1986 and 1996��2002, using a virtually identical questionnaire to obtain lifetime occupational and smoking history and several lifestyle covariates. Experts reviewed the detailed work history for each participant to assess exposure to several occupational agents, including formaldehyde. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for the associations between several metrics of formaldehyde exposure and lung cancer, adjusting for smoking and occupational and sociodemographic factors. Results In all, 2060 lung cancer cases and 2046 population controls were interviewed and assessed for exposure. About 25% of subjects had ever been occupationally exposed to formaldehyde. The adjusted OR for lung cancer was 1.06 (95% CI 0.89��1.27) comparing ever versus never exposure to formaldehyde. Analyses for age at first exposure, average, and peak intensity of exposure also suggested an absence of association between formaldehyde exposure and lung cancer risk. Results did not vary by sex, lifetime smoking intensity, or histological subtype. Conclusions No marked increases in lung cancer risk related to workplace formaldehyde exposure were observed. Study participants were mainly exposed at low concentration levels, which should be considered in the interpretation of our findings. by Mahboubi A, Koushik A, Siemiatycki J, Lavou� J, Rousseau M-C. doi:10.5271/sjweh.3342

Shift work and long-term injury among police officers

Mon, 07 Jan 2013 22:57:04 +0200

Objective Our previous work has suggested that the incidence of any occurrence of injury leave among police officers was higher on night shifts. In this study, we extended our inquiry to determine whether the incidence of long-term injury leave varies across shifts. Methods Police officers (N=419) from an urban department were included in the analysis. Daily payroll work history data from 1994�2010 was collected. Injury leave duration was examined ranging from ≥1�≥90 days. Poisson regression models were used to compute incidence rates (IR) and incidence rate ratios (IRR) of long-term injury. Results Cumulative incidence of injury for different durations of leave defined as ≥1, ≥5, ≥10, ≥15, ≥30, and ≥90 days were 61.3%, 45.4%, 39.9%, 33.9%, 26.5%, and 9.6% respectively. Age-and gender adjusted IRR of long-term injury (≥90 days) for night versus day shifts was IRR 3.12, 95% confidence interval (95% CI) 1.35�7.21 and IRR 2.21, 95% CI 1.04�4.68, for night versus afternoon shifts. Among all durations examined, the largest IRR was for injury ≥90 days, night versus day shifts (IRR 3.12, 95% CI 1.35�7.21). Conclusions Night shift work was significantly associated with long-term injury among police officers after adjustment for age and gender. Although type of injury was not available, it is possible that variation in injury type across shifts might account for some of this association. by Violanti JM, Fekedulegn D, Andrew ME, Charles LE, Hartley TA, Vila B, Burchfiel CM. doi:10.5271/sjweh.3338

Psychosocial working conditions, occupational groups, and risk of disability pension due to mental diagnoses: a cohort study of 43 000 Swedish twins

Mon, 17 Dec 2012 21:22:12 +0200

Objectives The aim of this study was to investigate associations between psychosocial working conditions, occupational groups defined by sector, and disability pension (DP) with mental diagnoses while accounting for familial confounding. Methods A prospective population-based cohort study was conducted, including all Swedish twins who, in January 1993, were living and working in Sweden and not on old-age pension or DP (N=42 715). The twins were followed from 1993�2008 regarding DP. Data on DP, exposures, and covariates were obtained from national registries. Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (95% CI) were constructed for the whole cohort, and for discordant twin pairs. Results The associations for the whole cohort between DP with mental diagnoses and (i) job demands (HR 1.23, 95% CI 1.06�1.43), (ii) job control (HR 0.91, 95% CI 0.83�0.99), (iii) healthcare and social work (HR 1.41, 95% CI 1.04�1.92), and (iv) service and military work (HR 2.07, 95% CI 1.37�3.14) remained after accounting for possible confounders, including familial factors, while the associations between DP and (i) social support, (ii) type of jobs, and (iii) some of the occupational groups were attenuated, becoming non-significant. In the discordant twin pair analyses, commercial work was significantly associated with lower risk of DP (HR 0.55, 95% CI 0.32�0.95). Conclusions One unit increase in job demands and working in the occupational groups healthcare and social work or service and military work seem to be risk factors of DP with mental diagnoses, independent from various background factors including familial ones. However, one unit increase in job control or working in commercial work seem to be protective factors of such DP, accounting for confounding factors of this study. by Samuelsson �, Ropponen A, Alexanderson K, Svedberg P. doi:10.5271/sjweh.3337

Miscarriage and occupational activity: a systematic review and meta-analysis regarding shift work, working hours, lifting, standing, and physical workload

Wed, 12 Dec 2012 17:07:10 +0200

Objective Previous studies have indicated that shift work, long working hours, and prevalent workplace exposures such as lifting, standing, and physical workload increase the risk of miscarriage, but the evidence is conflicting. We conducted a systematic review of original research reports. Methods A search in Medline and EMBASE 1966�2012 identified 30 primary papers reporting the relative risk (RR) of miscarriage according to ≥1 of 5 occupational activities of interest. Following an assessment of completeness of reporting, confounding, and bias, each risk estimate was characterized as more or less likely to be biased. Studies with equivalent measures of exposure were pooled to obtain a weighted common risk estimate. Sensitivity analyses excluded studies most likely to be biased. Results Working fixed nights was associated with a moderately increased risk of miscarriage (pooled RR 1.51 [95% confidence interval (95% CI) 1.27�1.78, N=5), while working in 3-shift schedules, working for 40�52 hours weekly, lifting >100 kg/day, standing >6�8 hours/day and physical workload were associated with small risk increments, with the pooled RR ranging from 1.12 (3-shift schedule, N=7) to 1.36 (working hours, N=10). RR for working hours and standing became smaller when analyses were restricted to higher quality studies. Conclusions These largely reassuring findings do not provide a strong case for mandatory restrictions in relation to shift work, long working hours, occupational lifting, standing, and physical workload. Considering the limited evidence base, however, it may be prudent to advise women against work entailing high levels of these exposures and women with at-risk pregnancies should receive tailored individual counseling. by Bonde JP, J�rgensen KT, Bonzini M, Palmer KT. doi:10.5271/sjweh.3336

Notification of occupational disease and the risk of work disability: a two-year follow-up study

Thu, 06 Dec 2012 21:44:02 +0200

Objectives The aim of this study was to analyze if notification of an occupational disease increases the risk of work disability. Methods We included 2304 patients examined at the Department of Occupational Medicine, Aarhus University Hospital, 1998�2005 and followed them for two years. A total of 564 patients were notified of an occupational disease when they were examined at baseline and 1740 patients were not. We obtained weekly information on sick payment, unemployment payment, disability pension, rehabilitation benefit, and other social benefits during the two years of follow-up from a national register. Using Cox regression models, we analyzed notification and adjusted hazard ratios (HR_adj) of work disability (defined as >12 weeks of social benefits during the first or second year of follow-up). Results Prior to notification, notified patients had higher levels of clinical, occupational, and social characteristics that predict poorer vocational prognosis. Analyses that adjusted for these differences showed an increased risk of work disability following notification for patients who were working when notified at baseline (HR_adj 1.46, 95% CI 1.17�1.82). No effect was seen for patients who were not working. Conclusions Notification of an occupational disease may, as an unintended side effect, increase the risk of work disability. A cautious interpretation is warranted because data analyses may not fully have accounted for the poorer vocational prognosis already present at baseline. by Kolstad HA, Christensen MV, Jensen LD, Schl�nssen V, Thulstrup AM, Bonde JP. doi:10.5271/sjweh.3335

Occupational lifting during pregnancy and risk of fetal death in a large national cohort study

Mon, 03 Dec 2012 18:15:09 +0200

Objective The aim of the present study was to examine the association between occupational lifting and the risk of fetal death according to gestational age. Methods We used data from the Danish National Birth Cohort (1996�2002). Among 71 500 occupationally active women, 2886 experienced a fetal death. Information on lifting and relevant covariates was collected in interviews around week 16 of pregnancy. The majority of fetal losses (N=2032) happened before the scheduled interview, and exposure data were collected retrospectively from these women. We analyzed early miscarriage (≤12 weeks), late miscarriage (13�21 weeks), and stillbirth (≥22 weeks), using Cox-regression models with gestational age as the underlying time variable. Results The adjusted early miscarriage risk increased with frequency of daily lifts and total burden lifted per day. For example, the hazard ratio was 1.38 [95% confidence interval (95% CI) 1.10�1.74] for a total weight load per day of 101�200 kg and 2.02 (95% CI 1.23�3.33) for a daily load >1000 kg as compared to non-lifters (P for trend <0.0001). Late miscarriage was associated with total daily weight load (P for trend=0.0073) but not with number of lifts per day. There was no association between occupational lifting and stillbirth. Conclusions In the present study, the risk of miscarriage increased with the number of lifts and total burden lifted per day at work. There may be a case for advising pregnant women against heavy lifting in particular during early pregnancy. by Juhl M, Strandberg-Larsen K, Larsen PS, Andersen PK, Svendsen SW, Bonde JP, Nybo Andersen A-M. doi:10.5271/sjweh.3333

Long working hours and health status among employees in Europe: between-country differences

Thu, 29 Nov 2012 03:49:14 +0200

Objectives This study aimed to (i) identify family responsibilities associated with moderately long working hours (41�60 hours a week); (ii) examine the relationship between moderately long working hours and three health outcomes; and (iii) analyze whether patterns differ by welfare state regimes. Methods The sample was composed of all employees aged 16�64 years working 30�60 hours a week interviewed in the 2005 European Working Conditions Survey (9288 men and 6295 women). We fitted multiple logistic regression models separated by sex and welfare state regime typologies. Results Married males were more likely to work long hours in countries with male breadwinner models whereas family responsibilities were related to long working hours among both sexes in countries with dual breadwinner models. The association between long working hours and health was (i) stronger among men in countries with male breadwinner models, primarily in Anglo-Saxon countries [adjusted odds ratio (OR_adj) associated with working 51�60 hours of 6.43, 6.04 and 9.60 for work-related poor health status, stress and psychological distress, respectively); (ii) similar among both sexes in Nordic countries; and (iii) stronger among women in Eastern European countries. Conclusions In the European Union of 25 members (EU-25), working moderately long hours is associated with poor health outcomes with different patterns depending on welfare state regimes. The findings from this study suggest that the family responsibilities and breadwinner models can help explain the relationship between long working hours and health status. by Artazcoz L, Cort�s I, Escrib�-Ag�ir V, Bartoll X, Basart H, Borrell C