Knut Skyberg

Risk factors for long-term absence due to psychiatric sickness: a register-based 5-year follow-up from the Oslo health study.

Objective: To identify individual and work-related predictors of long-term (>8 weeks) sickness absence with psychiatric diagnoses (LSP). Methods: Data from the Oslo Health Study (response rate 46%) were linked to public registers. A total of 8333 subjects were followed from 2001 through 2005. Cox regression was used to compute hazard ratios for LSP. Results: At least one LSP was present in 7.8% of women and 3.9% of men. Poor support from superior had an independent and moderate effect. Path and linear regression analyses indicated that the effect of support from superior was mediated through mental distress and not the other way around. Self-reported mental distress had a strong independent effect. Conclusions: Women had a higher risk of LSP than men. Low education and poor support from superior and mental distress were found to be determinants of LSP.

The Effect of Cleaning on Dust and the Health of Office Workers: An Intervention Study

Background: Office employees often experience symptoms that could be related to indoor air exposures. Methods: In an office building, 114 nonsmokers who had reported mucosal irritation complaints in a survey were selected to participate in a double-blind intervention study. The intervention was carried out in Oslo, Norway, during 1998. The offices of the intervention group were given a comprehensive cleaning, whereas the offices of the control group got a superficial cleaning as a placebo treatment. Dust concentration, health complaints, and nasal congestion were recorded before and after intervention or placebo. In the intervention group, the mean dust concentration was 67 &mgr;g/m3 before intervention and 50 &mgr;g/m3 after cleaning. Results: The intervention group reported a reduction in mucosal irritation complaints (a median reduction of 1.0 irritation index points on a scale 0–8) compared with no change in the control group. The odds ratio for reporting a 2-point reduction of the mucosal irritation symptom index was 3.5 (95% confidence interval [CI] = 1.2–9.1) in the intervention group compared with the control group. Nasal congestion, measured by acoustic rhinometry, was also reduced in the intervention group. The odds ratio for reduction in nasal congestion above the 70th percentile was 4.2 (CI = 1.3–11) in the intervention group versus the control group Conclusions: This experimental field trial shows that comprehensive cleaning reduces the airborne dust in offices, and also can reduce mucosal symptoms and nasal congestion.

“Inclusive working life in Norway”: a registry-based five-year follow-up study

BackgroundIn 2001, the Norwegian authorities and major labour market partners signed an agreement regarding ‘inclusive working life’ (IW), whereby companies that participate are committed to reducing sickness absence. Our main aim was to determine the effect of the IW program and work characteristics by gender on long-term (>8 weeks) sickness absence (LSA).MethodsSelf-reported data on work characteristics from the Oslo Health Study were linked to registry-based data on IW status, education and LSA. From 2001–2005, 10,995 participants (5,706 women and 5,289 men) aged 30, 40, 45 and 60 years were followed. A Cox regression was used to compute hazard ratios (HR) for LSA risk. The cohort was divided into an IW group (2,733 women and 2,058 men) and non-IW group (2,973/3,231).Results43.2% and 41.6% of women and 22.3%/24.3% of men (IW / non-IW, respectively) experienced at least one LSA. In a multivariate model, statistically significant risk factors for LSA were low education (stronger in men), shift work/night work or rotating hours (strongest in men in the non-IW group), and heavy physical work or work involving walking and lifting (men only and stronger in the non-IW group). Among men who engaged in shift work, the LSA risk was significantly lower in the IW group.ConclusionsOur results could suggest that IW companies that employ many men in shift work have implemented relevant efforts for reducing sickness absence. However, this study could not demonstrate a significant effect of the IW program on the overall LSA risk.

Radiographic evidence of pulmonary fibrosis and possible etiologic factors at a nickel refinery in NorwayPresented at the Sixth International Symposium on Metal Ions in Biology and Medicine, San Juan, Puerto Rico, USA, May 7?10, 2000.

Animal studies have shown that nickel compounds may induce pulmonary fibrosis, but so far only limited documentation in humans has been available. Radiographs of 1046 workers in a nickel refinery in Norway were read blindly and independently by three NIOSH certified B-readers, according to the ILO standards. Pulmonary fibrosis (PF) was defined as a median reading of ILO score > or = 1/0 and following this criterion, 47 cases (4.5%) were identified. In logistic regression models, controlling for age and smoking, there was evidence of increased risk of PF with cumulative exposure to soluble nickel or sulfidic nickel (p = 0.04 for both). For metallic nickel a p-value of 0.07 was found. For soluble nickel there was a dose-response trend for 4 categories of cumulated exposure. In the group with the highest cumulative exposure to soluble nickel (low exposure as reference), the crude odds ratio for PF was 4.34 (95% CI 1.75-10.77). The risk adjusted for age, smoking, asbestos and sulfidic nickel was 2.24 (0.82-6.16), with a dose-response trend. The corresponding figures for sulfidic nickel were 5.06 (1.70-15.09, crude) and 2.04 (0.54-7.70, adjusted for age, smoking, asbestos and soluble nickel). However, the dose-response trend was less clear for sulfidic nickel. Controlling for estimated asbestos exposure at the refinery tended to increase the odds ratios of soluble and sulfidic nickel. This study indicates that in addition to age and smoking exposure to soluble and sulfidic nickel compounds are risk factors of PF in humans. Since the number of cases identified in this study is small and undetected confounders may have been present, further studies in other cohorts are appropriate.

Longitudinal lung function decline among workers in a nitrate fertilizer production plant

Abstract Background: This study examines the possible effect of exposure to aerosols and gases on lung function in a fertilizer plant in Norway. Methods: Dynamic lung volumes (FVC and FEV1) of 383 workers were measured in 2007 and 2010. During the follow-up period, most workers performed tasks with low exposure levels of acid aerosols and inorganic gases. The overall median inhalable and thoracic aerosol exposure levels were 1·1 and 0·21 mg/m3, respectively. A questionnaire on respiratory symptoms was provided. Results: During the follow-up period, there was an adjusted decrease of FEV1 of 18 ml/year (P<0·001). The respiratory symptoms score was low during follow-up. Conclusions: Work in this fertilizer industry may lead to an excessive lung function decline. We have, however, not been able to find any plausible exposure related explanation for the overall lung function decline.

Longitudinal decline in pulmonary diffusing capacity among nitrate fertilizer workers

BACKGROUND This study is part of a 3-year follow-up of lung function among nitrate fertilizer production workers. AIMS To study the possible adverse effects of occupational exposure to aerosols and gases on pulmonary diffusing capacity. METHODS A longitudinal study of a cohort of fertilizer workers who performed single-breath carbon monoxide diffusing capacity (DLco) tests and spirometry in 2007 and 2010. The workers completed a questionnaire on respiratory symptoms and smoking habits. Exposure to mineral dust, acid aerosols and inorganic gases was measured. The overall median inhalable and thoracic aerosol mass concentrations were 1.1mg/m(3) (min-max: <0.93-45) and 0.21mg/m(3) (min-max: <0.085-11), respectively. RESULTS There were 308 participants in 2007 with 168 returning subjects in 2010. Overall, we found a statistically significant decline in the DLco of 0.068 mmol/min/kPa/year, adjusted for gender, age, height, weight, smoking status and doctor-diagnosed asthma during the 3-year follow-up (P < 0.01). The change in DLco did not vary significantly between the various job groups. Subjects with respiratory symptoms did not show a larger decline in DLco than those without symptoms. CONCLUSIONS This study indicates a larger than expected decline in the DLco of fertilizer workers during a 3-year follow-up. However, the decline was not related to specific exposures at work, or to possible covariates of exposure.