Hilde P. Notø

Exposure to thoracic dust, airway symptoms and lung function in cement production workers

Cement dust exposure has previously been associated with airway symptoms and ventilatory impairment. The aim of the present study was to examine lung function and airway symptoms among employees in different jobs and at different levels of exposure to thoracic dust in the cement production industry. At the start of a 4-yr prospective cohort study in 2007, exposure to cement dust, symptoms and lung function were recorded cross-sectionally in 4,265 employees in 24 European cement plants. Bronchial exposure was assessed by 2,670 full-shift dust samples with cyclones collecting the thoracic aerosol fraction. A job exposure matrix was constructed by grouping dust concentrations according to job type and plant. Elevated odds ratios for symptoms and airflow limitation (range 1.2–2.6 in the highest quartile), but not for chronic bronchitis, were found in the higher quartiles of exposure compared with the lowest quartile. Forced expiratory volume in 1 s (FEV1) showed an exposure–response relationship with a 270-mL deficit of FEV1 (95% CI 190–300 mL) in the highest compared with the lowest exposure level. The results support the hypothesis that exposure to dust in cement production may lead to respiratory symptoms and airway obstruction.

A cross-shift study of lung function, exhaled nitric oxide and inflammatory markers in blood in Norwegian cement production workers

Objectives To study possible effects of aerosol exposure on lung function, fractional exhaled nitric oxide (FeNO) and inflammatory markers in blood from Norwegian cement production workers across one work shift (0 to 8 h) and again 32 h after the non-exposed baseline registration. Methods 95 workers from two cement plants in Norway were included. Assessment of lung function included spirometry and gas diffusion pre- and post-shift (0 and 8 h). FeNO concentrations were measured and blood samples collected at 0, 8 and 32 h. Blood analysis included cell counts of leucocytes and mediators of inflammation. Results The median respirable aerosol level was 0.3 mg/m3 (range 0.02–6.2 mg/m3). FEV1, FEF25–75% and DLCO decreased by 37 ml (p=0.04), 170 ml/s (p<0.001) and 0.17 mmol/min/kPa (p=0.02), respectively, across the shift. A 2 ppm reduction in FeNO between 0 and 32 h was detected (p=0.01). The number of leucocytes increased by 0.6×109 cells/l (p<0.001) across the shift, while fibrinogen levels increased by 0.02 g/l (p<0.001) from 0 to 32 h. TNF-α level increased and IL-10 decreased across the shift. Baseline levels of fibrinogen were associated with the highest level of respirable dust, and increased by 0.39 g/l (95% CI 0.06 to 0.72). Conclusions We observed small cross-shift changes in lung function and inflammatory markers among cement production workers, indicating that inflammatory effects may occur at exposure levels well below 1 mg/m3. However, because the associations between these acute changes and personal exposure measurements were weak and as the long-term consequences are unknown, these findings should be tested in a follow-up study.

The effect of dust-protective respirator mask and the relevance of work category on urinary 1-hydroxypyrene concentration in PAH exposed electrode paste plant workers.

Large amounts of polycyclic-aromatic hydrocarbons (PAH) are found in the work environment of electrode paste workers. Inhalation and skin uptake are both important routes for PAH exposure. We have studied the effect of dust-protective respirator masks by measuring urinary 1-hydroxypyrene as a biomarker for PAH exposure. Eighteen workers divided into work categories at the factory were monitored by personal air sampling and urinary 1-hydroxypyrene every work shift for two consecutive weeks. In the second week of the study, the workers were encouraged to wear respirator masks persistently, which resulted in a significant reduction in urinary 1-hydroxypyrene in end-of-shift samples (paired t-test, P = 0.009). When correcting urinary 1-hydroxypyrene for ambient air pyrene we found on average 41% reduction in urinary 1-hydroxypyrene concentration in the second week of the intervention study. There was a work-category dependent variation in the correlation between end-of-shift urinary 1-hydroxypyrene samples and pyrene measured in the breathing zone of the workers, most likely due to variable skin uptake of pyrene; the overall correlation coefficient was 0.26 (P = 0.015). The 1-hydroxypyrene concentration in pre- and post-shift urine samples varied between 0.7 and 69.6 mumol/mol creatinine in the normal work week, and depended on the work category. The particulate PAH exposure ranged from 0.6 to 21.4 micrograms/m3. The ratio of particulate pyrene to benzo[a]pyrene varied from 1.6 to 8.0 amongst the various work categories within the same plant. Multiple regression analysis showed that smoking and work day are explanatory variables for the concentration of 1-hydroxypyrene in urine. Thirty-nine percent of the variation in the urinary 1-hydroxypyrene level at the end of shift could be explained by the independent variables pyrene concentration in air, smoking habits, work day, use of respiratory mask, work category and age.

Correlation between urinary 1-hydroxypyrene and ambient air pyrene measured with an inhalable aerosol sampler and a total dust sampler in an electrode paste plant

The aim of this study was to investigate whether the use of an inhalable aerosol sampler would improve the correlation between urinary 1-hydroxypyrene and occupational pyrene exposure compared to measurements with a total dust sampler in an electrode paste plant. PAHs were collected on a filter and adsorbent by a 37-mm closed-face total aerosol sampler and an open-face sampler for inhalable aerosol from the Institute of Occupational Medicine (IOM). 1-Hydroxypyrene in pre- and post-shift urine samples was quantitated by high performance liquid chromatography (HPLC). In this study, the use of the IOM sampler resulted in approximately four times higher concentrations of particulate PAH and pyrene than the total dust sampler. The correlation between pyrene levels measured with the two samplers was good with a correlation coefficient of 0.83. The correlation between workplace air pyrene and 1-hydroxypyrene in post-shift urine was poor (r = -0.12), but a small non-significant improvement was found with the IOM sampler (r = 0.11). In this factory the use of an inhalable aerosol sampler had only marginal effect on the correlation between 1-hydroxypyrene in urine and breathing zone pyrene. These results indicate that skin exposure is an important route of PAH uptake in this plant.

Exposure to Thoracic Aerosol in a Prospective Lung Function Study of Cement Production Workers

INTRODUCTION An exposure study was conducted as part of a multi-national longitudinal study of lung function in cement production workers. AIM To examine exposure to thoracic aerosol among cement production workers during a 4-year follow-up period. METHODS Personal shift measurements of thoracic aerosol were conducted among the cement production workers within seven job types, 22 plants, and eight European countries (including Turkey) in 2007, 2009, and 2011. The thoracic sub-fraction was chosen as the most relevant aerosol fraction related to obstructive dynamic lung function changes. Production factors, job type, and respirator use were recorded by questionnaire. The exposure data were log-transformed before mixed models analysis and results were presented by geometric mean (GMadj) exposure levels adjusted for plant or job type, worker, and season as random effects. RESULTS A total of 6111 thoracic aerosol samples were collected from 2534 workers. Repeated measurements were obtained from 1690 of these workers. The GMadj thoracic aerosol levels varied between job types from 0.20 to 1.2mg m(-3). The highest exposure levels were observed for production, cleaning, and maintenance workers (0.79-1.2mg m(-3)) and could reach levels where the risk of lung function loss may be increased. The lowest levels were found for administrative personnel (0.20mg m(-3)) serving tasks in the production areas. Office work was not monitored. GMadj exposure levels between plants ranged from 0.19 to 2.0mg m(-3). The time of year/season contributed significantly to the total variance, but not year of sampling. Production characteristics explained 63% of the variance explained by plant. Workers in plants with the highest number of employees (212-483 per plant) were exposed at a level more than twice as high as those in plants with fewer employees. Other production factors such as cement production, bag filling, and tidiness were significant, but explained less of the exposure variability. These determinants factors can be useful in qualitative exposure assessment and exposure prevention in the cement production industry. Respirator use was minor at exposure levels <0.5mg m(-3) but more common at higher levels. CONCLUSION Production, cleaning, and maintenance work were the job types with highest exposure to thoracic aerosol in cement production plants. However, plant had an even larger effect on exposure levels than job type. The number of employees was the most important factor explaining differences between plants. Exposure reached levels where the risk of lung function loss may be increased. No significant differences in exposure between sampling campaigns were observed during the 4-year study period.

Thoracic dust exposure is associated with lung function decline in cement production workers

We hypothesised that exposure to workplace aerosols may lead to lung function impairment among cement production workers. Our study included 4966 workers in 24 cement production plants. Based on 6111 thoracic aerosol samples and information from questionnaires we estimated arithmetic mean exposure levels by plant and job type. Dynamic lung volumes were assessed by repeated spirometry testing during a mean follow-up time of 3.5 years (range 0.7–4.6 years). The outcomes considered were yearly change of dynamic lung volumes divided by the standing height squared or percentage of predicted values. Statistical modelling was performed using mixed model regression. Individual exposure was classified into quintile levels limited at 0.09, 0.89, 1.56, 2.25, 3.36, and 14.6 mg·m−3, using the lowest quintile as the reference. Employees that worked in administration were included as a second comparison group. Exposure was associated with a reduction in forced expiratory volume in 1 s (FEV1), forced expiratory volume in 6 s and forced vital capacity. For FEV1 % predicted a yearly excess decline of 0.84 percentage points was found in the highest exposure quintile compared with the lowest. Exposure at the higher levels found in this study may lead to a decline in dynamic lung volumes. Exposure reduction is therefore warranted. Cement dust exposure at levels comparable to stated workplace exposure limits may lead to obstructive lung changes http://ow.ly/Zl7ny

Job Tasks as Determinants of Thoracic Aerosol Exposure in the Cement Production Industry

Background The aims of this study were to identify important determinants and investigate the variance components of thoracic aerosol exposure for the workers in the production departments of European cement plants. Methods Personal thoracic aerosol measurements and questionnaire information (Notø et al., 2015) were the basis for this study. Determinants categorized in three levels were selected to describe the exposure relationships separately for the job types production, cleaning, maintenance, foreman, administration, laboratory, and other jobs by linear mixed models. The influence of plant and job determinants on variance components were explored separately and also combined in full models (plant&job) against models with no determinants (null). The best mixed models (best) describing the exposure for each job type were selected by the lowest Akaike information criterion (AIC; Akaike, 1974) after running all possible combination of the determinants. Results Tasks that significantly increased the thoracic aerosol exposure above the mean level for production workers were: packing and shipping, raw meal, cement and filter cleaning, and de-clogging of the cyclones. For maintenance workers, time spent with welding and dismantling before repair work increased the exposure while time with electrical maintenance and oiling decreased the exposure. Administration work decreased the exposure among foremen. A subjective tidiness factor scored by the research team explained up to a 3-fold (cleaners) variation in thoracic aerosol levels. Within-worker (WW) variance contained a major part of the total variance (35-58%) for all job types. Job determinants had little influence on the WW variance (0-4% reduction), some influence on the between-plant (BP) variance (from 5% to 39% reduction for production, maintenance, and other jobs respectively but an 79% increase for foremen) and a substantial influence on the between-worker within-plant variance (30-96% for production, foremen, and other workers). Plant determinants had little influence on the WW variance (0-2% reduction), some influence on the between-worker variance (0-1% reduction and 8% increase), and considerable influence on the BP variance (36-58% reduction) compared to the null models. Conclusion Some job tasks contribute to low levels of thoracic aerosol exposure and others to higher exposure among cement plant workers. Thus, job task may predict exposure in this industry. Dust control measures in the packing and shipping departments and in the areas of raw meal and cement handling could contribute substantially to reduce the exposure levels. Rotation between low and higher exposed tasks may contribute to equalize the exposure levels between high and low exposed workers as a temporary solution before more permanent dust reduction measures is implemented. A tidy plant may reduce the overall exposure for almost all workers no matter of job type.

0406 Prospective monitoring of exposure and lung function among cement production workers – is drop out from the study associated with respiratory health at inclusion?

Objectives In this study we aimed to estimate the associations between respiratory health at inclusion and drop-out from a 4-year longitudinal study of lung function among cement production workers in Europe and Turkey. Method Non-administration workers (n = 3203) aged 17–54 yrs in 22 cement production plants in eight countries were included. Geometric mean (GM) exposure to the thoracic fraction of the workplace aerosol was allocated individually by job type and plant from a database of 6111 measurements from the follow-up study. Drop out was analysed in logistic regression with year of hire, exposure level, airway symptoms, chronic obstructive pulmonary disease (COPD) and use of airway protection at inclusion as explanatory variables. COPD was defined as FEV1/FVC < 0.7. Results COPD at inclusion was associated with drop out, but only among those hired 6–10 years before inclusion (OR 2.4 [CI 95% 1.1–5.5]). GM exposure exceeding a level of 1.61 mg/m3 was associated with drop out (OR= 1.9; CI 95% 1.3–2.7) compared to exposure below 0.42 mg/m3. The use of respiratory protection at inclusion was inversely associated with drop out (OR 0.6 [CI 95% 0.4–0.9]). Age, sex, allergy, asthma and previous occupational exposure to dust and gases did not confound the associations. Conclusions Workers in the highest exposed group had increased risk, while those who reported using a respiratory mask had reduced risk of dropping out. Participants classified with COPD at inclusion were to some extent depleted from the study, but only among those hired 6–10 years before their inclusion.