Journal of Occupational Medicine and Toxicology - Latest articles

The role of cumulative physical work load in symptomatic knee osteoarthritis - a case-control study in Germany

2008-07-14

Objectives To examine the dose-response relationship between cumulative exposure to kneeling and squatting as well as to lifting and carrying of loads and symptomatic knee osteoarthritis (OA) in a population-based case-control study. Methods: In five orthopedic clinics and five practices we recruited 295 male patients aged 25 to 70 with radiographically confirmed knee osteoarthritis associated with chronic complaints. A total of 327 male control subjects were recruited. Data were gathered in a structured personal interview. To calculate cumulative exposure, the self-reported duration of kneeling and squatting as well as the duration of lifting and carrying of loads were summed up over the entire working life. Results: The results of our study support a dose-response relationship between kneeling/squatting and symptomatic knee osteoarthritis. For a cumulative exposure to kneeling and squatting > 10.800 hours, the risk of having radiographically confirmed knee osteoarthritis as measured by the odds ratio (adjusted for age, region, weight, jogging/athletics, and lifting or carrying of loads) is 2.4 (95% CI 1.1-5.0) compared to unexposed subjects. Lifting and carrying of loads is significantly associated with knee osteoarthritis independent of kneeling or similar activities. Conclusions: As the knee osteoarthritis risk is strongly elevated in occupations that involve both kneeling/squatting and heavy lifting/carrying, preventive efforts should particularly focus on these "high-risk occupations".

Incidence of Raynaud's phenomenon in relation to hand-arm vibration exposure among male workers at an engineering plant a cohort study

Mats Hagberg, Lage Burström, Ronnie Lundström and Tohr Nilsson — 2008-06-16

Background: The objective of this study was to assess the incidence of Raynaud's phenomenon in relation to hand-arm vibration exposure in a cohort consisting of male office and manual workers. Methods: The baseline population consisted of 94 office and 147 manual workers at an engineering plant. Raynaud's phenomenon (RP) was assessed at baseline and at follow up (at 5, 10 and 15 years). A retrospective and a prospective cohort analysis of data were done. Hand-arm vibration exposure dose was defined as the product of exposure duration and the weighted hand-arm vibration exposure value according to ISO 5349-1. Results: The retrospective/prospective incidence of Raynaud's phenomenon was 16/14 per 1000 exposure years among exposed and 2.4/5.0 per 1000 years among the not exposed. The retrospective dose response curve based on 4 dose classes showed that class 2, 3 and 4 had similar response and showed higher incidence than the not-exposed. The dose with RP response to hand-arm vibration corresponded to a 10 year A(8) value between 0.4–1.0 m/s2. Conclusion: The results indicate that the EU directive on an action value for hand-arm vibration of 2.5 m/s2 is not too low. Rather, it suggests that employers should take on actions even at exposure values of 1 m/s2A(8).

Cancer risk among residents of Rhineland-Palatinate winegrowing communities: a cancer-registry based ecological study

2008-06-06

AimTo investigate the cancer risk among residents of Rhineland-Palatinate winegrowing communities in an ecological study. Methods: On the basis of the Rhineland-Palatinate cancer-registry, we calculated age-adjusted incidence rate ratios for communities with a medium area under wine cultivation (>5 to 20 percent) and a large area under wine cultivation (>20 percent) in comparison with communities with a small area under wine cultivation (>0 to 5 percent). In a side analysis, standardized cancer incidence ratios (SIR) were computed separately for winegrowing communities with small, medium and large area under wine cultivation using estimated German incidence rates as reference. Results: A statistically significant positive association with the extent of viniculture can be observed for non-melanoma skin cancer in both males and females, and additionally for prostate cancer, bladder cancer, and non-Hodgkin lymphoma in males, but not in females. Lung cancer risk is significantly reduced in communities with a large area under cultivation. In the side-analysis, elevated SIR for endocrine-related tumors of the breast, testis, prostate, and endometrium were observed. Conclusion: This study points to a potentially increased risk of skin cancer, bladder cancer, and endocrine-mediated tumors in Rhineland-Palatinate winegrowing communities. However, due to the explorative ecologic study design and the problem of multiple testing, these findings are not conclusve for a causal relationship.

Occupational allergy due to seafood delivery: Case report

Cornelia S Seitz, Eva B Bröcker and Axel Trautmann — 2008-05-30

Background: Sensitization to fish or crustaceans requires intensive skin contact and/or airway exposition and therefore especially workers in the seafood processing industry may develop an occupational seafood allergy. However, even in jobs with limited direct exposure, individuals with atopic disposition not using appropriate skin protection are at risk for developing occupational seafood allergy which requires termination of employment.Case presentationDue to increasing workload and pressure of time a truck driver in charge of seafood deliveries for 10 years neglected preventive measures such as wearing protective cloths and gloves which resulted in increasing direct skin contact to seafood or mucosal contact to splashing storage ice. Despite his sensitization to fish and crustaceans he tried to remain in his job but with ongoing incidental allergen exposure his symptoms progressed from initial contact urticaria to generalized urticaria, anaphylaxis and finally occupational asthma. Conclusion: Faulty knowledge and increased work load may impede time-consuming usage of preventive measures for occupational health and safety. In predisposed atopic individuals even minor allergen exposure during seafood distribution may lead to occupational seafood allergy. With ongoing allergen exposure progression to potentially life-threatening allergy symptoms may occur.

Neurological symptoms among dental assistants: a cross-sectional study

BE Moen, BE Hollund and T Riise — 2008-05-18

Background: Dental assistants help the dentist in preparing material for filling teeth. Amalgam was the filling material mostly commonly used in Norway before 1980, and declined to about 5% of all fillings in 2005. Amalgam is usually an alloy of silver, copper, tin and mercury. Copper amalgam, giving particularly high exposure to mercury was used in Norway until 1994. Metallic mercury is neurotoxic. Few studies of the health of dental assistants exist, despite their exposure to mercury. There are questions about the existence of possible chronic neurological symptoms today within this working group, due to this exposure. The aim of this study was to compare the occurrence of neurological symptoms among dental assistants likely to be exposed to mercury from work with dental filling material, compared to similar health personnel with no such exposure. Methods: All dental assistants still at work and born before 1970 registered in the archives of a trade union in Hordaland county of Norway were invited to participate (response rate 68%, n = 41), as well as a similar number of randomly selected assistant nurses (response rate 87%, n = 64) in the same age group. The participants completed a self-administered, mailed questionnaire, with questions about demographic variables, life-style factors, musculoskeletal, neurological and psychosomatic symptoms (Euroquest). Results: The dental assistants reported significant higher occurrence of neurological symptoms; psychosomatic symptoms, problems with memory, concentration, fatigue and sleep disturbance, but not for mood. This was found by analyses of variance, adjusting for age, education, alcohol consumption, smoking and personality traits. For each specific neurological symptom, adjusted logistic regression analyses were performed, showing that these symptoms were mainly from arms, hands, legs and balance organs. Conclusion: There is a possibility that the higher occurrence of neurological symptoms among the dental assistants may be related to their previous work exposure to mercury amalgam fillings. This should be studied further to assess the clinical importance of the reported symptoms.

Effort-reward imbalance and overcommitment in employees in a Norwegian municipality: a cross sectional study

Bjørn Lau — 2008-04-30

Background: The aim of this study was to validate a Norwegian version of the Effort-Reward Imbalance Questionnaire (ERI-Q). Methods: One thousand eight-hundred and three employees in a medium-sized Norwegian municipality replied to the ERI-Q, and health-related variables such as self-reported general health, psychological distress, musculoskeletal complaints, and work-related burnout were examined. Results: Sound psychometric properties were found for this Norwegian version of the ERI-Q. When the two dimensions of ERI and overcommitment were analyzed in four types of employees, the results showed that employees characterized by a combination of high values on ERI and overcommitment had more unfavorable health scores than others. Employees with low effort-reward and overcommitment scores had more favorable health scores. Employees with scores on the overcommitment and the effort-reward scales that are supposed to have opposite effects on health (that is, the combination of low overcommitment with a high effort-reward score and vice versa), had health scores somewhere in between the two other groups. Conclusion: Satisfactory psychometric properties were found for most of the latent factors in the ERI-Q. The findings also indicate that it may be fruitful to explore health conditions among employees with different combinations of effort-reward and overcommitment.

Self-reported work ability of Norwegian women in relation to physical and mental health, and to the work environment

2008-04-22

ObjectivesTo examine the self-reported level of work ability among female employees and the relationship between work ability and demographic characteristics, physical health, mental health, and various psychosocial and organizational work environment factors. Methods: Participants were 597 female employees with an average age of 43 years from urban and rural areas in Norway. Trained personnel performed a structured interview to measure demographic variables, physical health, and characteristics of the working environment. Mental health was assessed using the 25-item version of the Hopkins Symptoms Checklist (HSCL-25). Work ability was assessed using a question from the Graded Reduced Work Ability Scale. Results: Of the 597 female employees, 8.9% reported an extremely or very reduced ability to work. Twenty-four percent reported poor physical health and 21.9% reported mental distress (≥ 1.55 HSCL-25 cut-off). Women, who reported moderately and severely reduced work ability, did not differ a lot. Moderately reduced work ability increased with age and was associated with physical and mental health. Severely reduced work ability was strongly associated only with physical health and with unskilled occupation. Of eight work environment variables, only three yielded significant associations with work ability, and these associations disappeared after adjustment in the multivariate analysis. Conclusion: Results indicate that ageing, in addition to poor self-reported physical health and unskilled work, were the strongest factors associated with reduced work ability among female employees. Impact of work environment in general was visible only in univariate analysis.

The effects of a graduated aerobic exercise programme on cardiovascular disease risk factors in the NHS workplace: a randomised controlled trial

2008-02-28

Background: Sufficient levels of physical activity provide cardio-protective benefit. However within developed society sedentary work and inflexible working hours promotes physical inactivity. Consequently to ensure a healthy workforce there is a requirement for exercise strategies adaptable to occupational time constraint. This study examined the effect of a 12 week aerobic exercise training intervention programme implemented during working hours on the cardiovascular profile of a sedentary hospital workforce. Methods: Twenty healthy, sedentary full-time staff members of the North West London Hospital Trust cytology unit were randomly assigned to an exercise (n = 12; mean ± SD age 41 ± 8 years, body mass 69 ± 12 kg) or control (n = 8; mean ± SD age 42 ± 8 years, body mass 69 ± 12 kg) group. The exercise group was prescribed a progressive aerobic exercise-training programme to be performed 4 times a week for 8 weeks (initial intensity 65% peak oxygen consumption (VO2 peak)) and to be conducted without further advice for another 4 weeks. The control was instructed to maintain their current physical activity level. Oxygen economy at 2 minutes (2minVO2), 4 minutes (4minVO2), VO2 peak, systolic blood pressure (SBP), diastolic blood pressure (DBP), BMI, C-reactive protein (CRP), fasting glucose (GLU) and total cholesterol (TC) were determined in both groups pre-intervention and at 4 week intervals. Both groups completed a weekly Leisure Time Questionnaire to quantify additional exercise load. Results: The exercise group demonstrated an increase from baseline for VO2 peak at week 4 (5.8 ± 6.3 %) and 8 (5.0 ± 8.7 %) (P < 0.05). 2minVO2 was reduced from baseline at week 4 (-10.2 ± 10.3 %), 8 (-16.8 ± 10.6 %) and 12 (-15.1 ± 8.7 %), and 4minVO2 at week 8 (-10.7 ± 7.9 %) and 12 (-6.8 ± 9.2) (P < 0.05). There was also a reduction from baseline in CRP at week 4 (-0.4 ± 0.6 mg·L-1) and 8 (-0.9 ± 0.8 mg·L-1) (P < 0.05). The control group showed no such improvements. Conclusion: This is the first objectively monitored RCT to show that moderate exercise can be successfully incorporated into working hours, to significantly improve physical capacity and cardiovascular health.

A prospective study of decline in lung function in relation to welding emissions

Sigve W Christensen, Jens Peter Bonde and Øyvind Omland — 2008-02-26

Background: Numerous cross-sectional studies have reported reduced lung function among welders but limitations of exposure assessment and design preclude causal inference. The aim of this study was to investigate if long-term exposure to welding fume particulates accelerates the age-related decline in lung function. Methods: Lung function was measured by spirometry in 1987 and 2004 among 68 steel welders and 32 non-welding production workers. The decline in forced expiratory volume (FEV1) was analysed in relation to cumulated exposure to fume particulates among welders during the follow-up period. Results: Among smokers the decline in FEV1 through follow-up period was in average 150 ml larger among welders than non-welders while the difference was negligible among non-smokers. The results did not reach statistical significance and within welders the decline in lung function was not related to the cumulated welding particulate exposure during follow-up period Conclusion: Long-term exposure to welding emissions may accelerate the age-related decline of lung function but at exposure levels in the range of 1.5 to 6.5 mg/m3 the average annual excess loss of FEV1 is unlikely to exceed 25 ml in smokers and 10 ml in non-smokers.

Effect of montelukast on platelet activating factor- and tachykinin induced mucus secretion in the rat

Rene Schmidt, Petra Staats, David A Groneberg and Ulrich Wagner — 2008-02-20

Background: Platelet activating factor and tachykinins (substance P, neurokinin A, neurokinin B) are important mediators contributing to increased airway secretion in the context of different types of respiratory diseases including acute and chronic asthma. Leukotriene receptor antagonists are recommended as add-on therapy for this disease. The cys-leukotriene-1 receptor antagonist montelukast has been used in clinical asthma therapy during the last years. Besides its inhibitory action on bronchoconstriction, only little is known about its effects on airway secretions. Therefore, the aim of this study was to evaluate the effects of montelukast on platelet activating factor- and tachykinin induced tracheal secretory activity. Methods: The effects of montelukast on platelet activating factor- and tachykinin induced tracheal secretory activity in the rat were assessed by quantification of secreted 35SO4 labelled mucus macromolecules using the modified Ussing chamber technique. Results: Platelet activating factor potently stimulated airway secretion, which was completely inhibited by the platelet activating factor receptor antagonist WEB 2086 and montelukast. In contrast, montelukast had no effect on tachykinin induced tracheal secretory activity. Conclusion: Cys-leukotriene-1 receptor antagonism by montelukast reverses the secretagogue properties of platelet activating factor to the same degree as the specific platelet activating factor antagonist WEB 2086 but has no influence on treacheal secretion elicited by tachykinins. These results suggest a role of montelukast in the signal transduction pathway of platelet activating factor induced secretory activity of the airways and may further explain the beneficial properties of cys-leukotriene-1 receptor antagonists.