Magne Bråtveit

Increased risk of acute myelogenous leukemia and multiple myeloma in a historical cohort of upstream petroleum workers exposed to crude oil.

Benzene exposure has been shown to be related to acute myelogenous leukemia, while the association with multiple myeloma and non-Hodgkin lymphoma has been a much-debated issue. We performed a historical cohort study to investigate whether workers employed in Norway’s upstream petroleum industry exposed to crude oil and other products containing benzene have an increased risk of developing various subtypes of hematologic neoplasms. Using the Norwegian Registry of Employers and Employees we included all 27,919 offshore workers registered from 1981 to 2003 and 366,114 referents from the general working population matched by gender, age, and community of residence. The cohort was linked to the Cancer Registry of Norway. Workers in the job category “upstream operator offshore”, having the most extensive contact with crude oil, had an excess risk of hematologic neoplasms (blood and bone marrow) (rate ratio (RR) 1.90, 95% confidence interval (95% CI): 1.19–3.02). This was ascribed to an increased risk of acute myelogenous leukemia (RR 2.89, 95% CI: 1.25−6.67) and multiple myeloma (RR 2.49, 95% CI: 1.21–5.13). There were no statistical differences between the groups in respect to non-Hodgkin lymphoma. The results suggest that benzene exposure, which most probably caused the increased risk of acute myelogenous leukemia, also resulted in an increased risk of multiple myeloma.

Cement dust exposure and ventilatory function impairment: An exposure-response study

We investigated cumulative total cement dust exposure and ventilatory function impairment at a Portland cement factory in Tanzania. All 126 production workers were exposed. The control group comprised all 88 maintenance workers and 32 randomly chosen office workers. Exposed workers had significantly lower forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEF), FEV1/FVC, FVC%, FEV1% and PEF%, than controls adjusted for age, duration of employment, height, and pack-years. Cumulative total dust exposure was significantly associated with reduced FVC, forced expiratory volume in 1 second, and peak expiratory flow rate adjusted for age, height and pack-years. Cumulative total dust exposure more than 300 mg/m3 year versus lower than 100 mg/m3 years was significantly associated with increased risk of developing airflow limitation (odds ratio = 9.9). The current occupational exposure limit for total cement dust (10 mg/m3) appears to be too high to prevent respiratory health effects among cement workers.

Exposure to carcinogens for defined job categories in Norway’s offshore petroleum industry, 1970 to 2005

Objectives: To identify and describe the exposure to selected known and suspected carcinogenic agents, mixtures and exposure circumstances for defined job categories in Norway’s offshore petroleum industry from 1970 to 2005, in order to provide exposure information for a planned cohort study on cancer. Methods: Background information on possible exposure was obtained through company visits, including interviewing key personnel (n = 83) and collecting monitoring reports (n = 118) and other relevant documents (n = 329). On the basis of a previous questionnaire administered to present and former offshore employees in 1998, 27 job categories were defined. Results: This study indicated possible exposure to 18 known and suspected carcinogenic agents, mixtures or exposure circumstances. Monitoring reports were obtained on seven agents (benzene, mineral oil mist and vapour, respirable and total dust, asbestos fibres, refractory ceramic fibres, formaldehyde and tetrachloroethylene). The mean exposure level of 367 personal samples of benzene was 0.037 ppm (range: less than the limit of detection to 2.6 ppm). Asbestos fibres were detected (0.03 fibres/cm3) when asbestos-containing brake bands were used in drilling draw work in 1988. Personal samples of formaldehyde in the process area ranged from 0.06 to 0.29 mg/m3. Descriptions of products containing known and suspected carcinogens, exposure sources and processes were extracted from the collected documentation and the interviews of key personnel. Conclusions: This study described exposure to 18 known and suspected carcinogenic agents, mixtures and exposure circumstances for 27 job categories in Norway’s offshore petroleum industry. For a planned cohort study on cancer, quantitative estimates of exposure to benzene, and mineral oil mist and vapour might be developed. For the other agents, information in the present study can be used for further assessment of exposure, for instance, by expert judgement. More systematic exposure surveillance is needed in this industry. For future studies, new monitoring programmes need to be implemented.

Lung function reduction and chronic respiratory symptoms among workers in the cement industry: a follow up study

BackgroundThere are only a few follow-up studies of respiratory function among cement workers. The main aims of this study were to measure total dust exposure, to examine chronic respiratory symptoms and changes in lung function among cement factory workers and controls that were followed for one year.MethodsThe study was conducted in two cement factories in Ethiopia. Totally, 262 personal measurements of total dust among 105 randomly selected workers were performed. Samples of total dust were collected on 37-mm cellulose acetate filters placed in closed faced Millipore-cassettes. Totally 127 workers; 56 cleaners, 44 cement production workers and 27 controls were randomly selected from two factories and examined for lung function and interviewed for chronic respiratory symptoms in 2009. Of these, 91 workers; 38 cement cleaners (mean age 32 years), 33 cement production workers (36 years) and 20 controls (38 years) were examined with the same measurements in 2010.ResultsTotal geometric mean dust exposure among cleaners was 432 mg/m3. The fraction of samples exceeding the Threshold Limit Value (TLV) of 10 mg/m3 for the cleaners varied from 84-97% in the four departments. The levels were considerably lower among the production workers (GM = 8.2 mg/m3), but still 48% exceeded 10 mg/m3.The prevalence of all the chronic respiratory symptoms among both cleaners and production workers was significantly higher than among the controls.Forced Expiratory Volume in one second (FEV1) and FEV1/Forced Vital Capacity (FEV1/FVC) were significantly reduced from 2009 to 2010 among the cleaners (p < 0.002 and p < 0.004, respectively) and production workers (p < 0.05 and p < 0.02, respectively), but not among the controls.ConclusionsThe high prevalence of chronic respiratory symptoms and reduction in lung function is probably associated with high cement dust exposure. Preventive measures are needed to reduce the dust exposure.

High prevalence of respiratory symptoms among workers in the development section of a manually operated coal mine in a developing country: A cross sectional study

BackgroundFew studies of miners have been carried out in African countries; most are from South Africa, where the working conditions are assumed to be better than in the rest of Africa. Several studies have focused on respiratory disorders among miners, but development workers responsible for creating underground road ways have not been studied explicitly. This is the first study assessing the associations between exposure to dust and quartz and respiratory symptoms among coal mine workers in a manually operated coal mine in Tanzania, focusing on development workers, as they have the highest exposure to coal dust.MethodsA cross-sectional study was carried out among 250 production workers from a coal mine. Interviews were performed using modified standardized questionnaires to elicit information on occupational history, demographics, smoking habits and acute and chronic respiratory symptoms. The relationships between current dust exposure as well as cumulative respirable dust and quartz and symptoms were studied by group comparisons as well as logistic regression.ResultsWorkers from the development group had the highest dust exposure, with arithmetic mean of 10.3 mg/m3 for current respirable dust and 1.268 mg/m3 for quartz. Analogous exposure results for mine workers were 0.66 mg/m3 and 0.03 mg/m3, respectively; and for other development workers were 0.88 mg/m3 and 0.10 mg/m3, respectively.The workers from the development section had significantly higher prevalence of the acute symptoms of dry cough (45.7%), breathlessness (34.8%) and blocked nose (23.9%). In addition, development workers had significantly more chronic symptoms of breathlessness (17.0%) than the mine workers (6.4%) and the other production workers (2.4%). The highest decile of cumulative exposure to respirable dust was significantly associated with cough (OR = 2.91, 95% CI 1.06, 7.97) as were cumulative exposure to quartz and cough (OR = 2.87, CI 1.05, 7.88), compared with the reference consisting of the group of workers with the lowest quartile of the respective cumulative exposure.ConclusionThe development workers in a coal mine had more acute and chronic respiratory symptoms than the mine and the other production workers. In addition, there was an association between high cumulative coal dust and respiratory symptoms.

Benzene exposure and risk of lymphohaematopoietic cancers in 25,000 offshore oil industry workers.

Background:The aim of this work was to examine the risk of lymphohaematopoietic (LH) cancer according to benzene exposure among offshore workers.Methods:Cancer registry data were used to identify 112 cancer cases diagnosed during 1999–2011 in a cohort of 24 917 Norwegian men reporting offshore work between 1965 and 1999. Analyses were conducted according to a stratified case–cohort design with a reference subcohort of 1661 workers. Cox regression was used to estimate hazard ratios with 95% confidence intervals, adjusted for other benzene exposure and smoking.Results:Most workers were exposed to benzene for <15 years. The upper range values of average intensity and cumulative exposure were estimated to 0.040 p.p.m. and 0.948 p.p.m.-years, respectively. Risks were consistently elevated among exposed workers for all LH cancers combined and for most subgroups, although case numbers were small and yielded imprecise risk estimates. There was evidence of dose-related risk patterns according to cumulative exposure for acute myeloid leukaemia (AML), multiple myeloma (MM) (P trends 0.052 and 0.024, respectively), and suggestively so for chronic lymphocytic leukaemia (CLL) according to average intensity (P trend 0.094).Conclusions:Our results support an association between cumulative and intensity metrics of low-level benzene exposure and risk for AML, MM, and suggestively for CLL.

The impact of social and organizational factors on workers' use of personal protective equipment: a multilevel approach.

Objective: On the basis of the job demands-control-support model by Karasek and Theorell, we investigated how social and organizational factors influence workers’ use of personal protective equipment (PPE). Methods: A cross-sectional study was performed among 1420 workers in 203 motor vehicle-repair garages. Multilevel modeling was performed to account for the hierarchical structure of the data. Results: Social and management support correlated positively with PPE use at the worker level. Low demands measured at the garage level and having a health and safety management system at the garage also correlated with active use of PPE. An interaction effect between social support and garage-level demands was observed. Conclusions: In addition to health information and provision of PPE, focusing on social and organizational factors seems necessary to get more workers to comply with the instructions on PPE use.

Inter‐rater agreement in the assessment of exposure to carcinogens in the offshore petroleum industry

Objectives: To evaluate the reliability of an expert team assessing exposure to carcinogens in the offshore petroleum industry and to study how the information provided influenced the agreement among raters. Methods: Eight experts individually assessed the likelihood of exposure for combinations of 17 carcinogens, 27 job categories and four time periods (1970–1979, 1980–1989, 1990–1999 and 2000–2005). Each rater assessed 1836 combinations based on summary documents on carcinogenic agents, which included descriptions of sources of exposure and products, descriptions of work processes carried out within the different job categories, and monitoring data. Inter-rater agreement was calculated using Cohen’s kappa index and single and average score intraclass correlation coefficients (ICC) (ICC(2,1) and ICC(2,8), respectively). Differences in inter-rater agreement for time periods, raters, International Agency for Research on Cancer groups and the amount of information provided were consequently studied. Results: Overall, 18% of the combinations were denoted as possible exposure, and 14% scored probable exposure. Stratified by the 17 carcinogenic agents, the probable exposure prevalence ranged from 3.8% for refractory ceramic fibres to 30% for crude oil. Overall mean kappa was 0.42 (ICC(2,1) = 0.62 and ICC(2,8) = 0.93). Providing limited quantitative measurement data was associated with less agreement than for equally well described carcinogens without sampling data. Conclusion: The overall κ and single-score ICC indicate that the raters agree on exposure estimates well above the chance level. The levels of inter-rater agreement were higher than in other comparable studies. The average score ICC indicates reliable mean estimates and implies that sufficient raters were involved. The raters seemed to have enough documentation on which to base their estimates, but provision of limited monitoring data leads to more incongruence among raters. Having real exposure data, with the inherent variability of such data, apparently makes estimating exposure in a rigid semiquantitative manner more difficult.

Increased risk of oesophageal adenocarcinoma among upstream petroleum workers.

Objectives To investigate cancer risk, particularly oesophageal cancer, among male upstream petroleum workers offshore potentially exposed to various carcinogenic agents. Methods Using the Norwegian Registry of Employers and Employees, 24 765 male offshore workers registered from 1981 to 2003 was compared with 283 002 male referents from the general working population matched by age and community of residence. The historical cohort was linked to the Cancer Registry of Norway and the Norwegian Cause of Death Registry. Results Male offshore workers had excess risk of oesophageal cancer (RR 2.6, 95% CI 1.4 to 4.8) compared with the reference population. Only the adenocarcinoma type had a significantly increased risk (RR 2.7, 95% CI 1.0 to 7.0), mainly because of an increased risk among upstream operators (RR 4.3, 95% CI 1.3 to 14.5). Upstream operators did not have significant excess of respiratory system or colon cancer or mortality from any other lifestyle-related diseases investigated. Conclusion We found a fourfold excess risk of oesophageal adenocarcinoma among male workers assumed to have had the most extensive contact with crude oil. Due to the small number of cases, and a lack of detailed data on occupational exposure and lifestyle factors associated with oesophageal adenocarcinoma, the results must be interpreted with caution. Nevertheless, given the low risk of lifestyle-related cancers and causes of death in this working group, the results add to the observations in other low-powered studies on oesophageal cancer, further suggesting that factors related to the petroleum stream or carcinogenic agents used in the production process might be associated with risk of oesophageal adenocarcinoma.

Respiratory health in cleaners in Northern Europe : is susceptibility established in early life?

Rationale There is some evidence that maternal smoking increases susceptibility to personal smoking’s detrimental effects. One might question whether early life disadvantage might influence susceptibility to occupational exposure. Objectives In this cross-sectional study we investigated respiratory symptoms, asthma and self-reported chronic obstructive pulmonary disease (COPD) as related to working as a cleaner in Northern European populations, and whether early life factors influenced susceptibility to occupational cleaning’s unhealthy effects. Methods The RHINE III questionnaire study assessed occupational cleaning in 13,499 participants. Associations with respiratory symptoms, asthma and self-reported COPD were analysed with multiple logistic regressions, adjusting for sex, age, smoking, educational level, parent´s educational level, BMI and participating centre. Interaction of occupational cleaning with early life disadvantage (maternal smoking, severe respiratory infection <5 years, born during winter months, maternal age at birth >35 years) was investigated. Main Results Among 2138 ever-cleaners the risks of wheeze (OR 1.4, 95% CI 1.3–1.6), adult-onset asthma (1.5 [1.2–1.8]) and self-reported COPD (1.7 [1.3–2.2]) were increased. The risk increased with years in occupational cleaning (adult-onset asthma: ≤1 year 0.9 [0.7–1.3]; 1–4 years 1.5 [1.1–2.0]; ≥4 years 1.6 [1.2–2.1]). The association of wheeze with cleaning activity ≥4 years was significantly stronger for those with early life disadvantage than in those without (1.8 [1.5–2.3] vs. 1.3 [0.96–1.8]; pinteraction 0.035). Conclusions Occupational cleaners had increased risk of asthma and self-reported COPD. Respiratory symptom risk was particularly increased in persons with factors suggestive of early life disadvantage. We hypothesize that early life disadvantage may increase airway vulnerability to harmful exposure from cleaning agents later in life.