Post-shift changes in pulmonary function in a cement factory in eastern Saudi Arabia

[Granulomatous pleuritis and chylothorax caused by calcite inhalation in a Galgo Español dog]

A 6-year-old, male Galgo Español dog was presented with severe dyspnea. Radiography and ultrasonography revealed pleural effusion. Approximately 4 l of a milky and slightly reddish fluid were aspirated and drained from the thoracic cavity. Clinical chemistry examination of the fluid indicated a modified transudate with a high amount of triglycerides. On cytological examination, degenerated neutrophilic granulocytes, small lymphocytes, macrophages and chylomicrons were found. A chest tube was placed and computed tomography was performed, which indicated thickening of parietal and visceral pleura and enlargement of the sternal lymph node without abnormal findings in the lungs. During subsequent thoracoscopy disseminated proliferative masses, appearing as small white nodules, covering nearly the entire pleural surface were found and biopsies were taken for further analysis. Histopathologic diagnosis was a granulomatous pleuritis with intralesional birefringent foreign material. Energy dispensive x-ray emission analysis was used to determine the origin of the material. Scanning electron microscopy revealed high amounts of calcium containing foreign material (calcite) within the granulomas. An extended clinical history of the dog gave evidence that the animal had lived next to a construction site 15 months earlier and may well have inhaled the calcium-containing dust. Treatment with prednisolone was initiated, however the dog developed gastro-intestinal side effects and treatment was stalled after 10 weeks. Dyspnea and liquidothorax re-occurred 4 months later. A further attempt of immunosupressive treatment was commenced, using a combination of prednisolone and ciclosporine, which again was not tolerated by the patient. The dog finally developed pneumonia and was euthanized by the owner's request.

Association between exposure in the cement production industry and non-malignant respiratory effects: a systematic review

OBJECTIVES

Based on findings from a systematic literature search, we present and discuss the evidence for an association between exposure to cement dust and non-malignant respiratory effects in cement production workers.

DESIGN AND SETTING

Systematic literature searches (MEDLINE and Embase) were performed. Outcomes were restricted to respiratory symptoms, lung function indices, asthma, chronic bronchitis, chronic obstructive pulmonary disease, pneumoconiosis, induced sputum or fraction of exhaled nitric oxide (FeNO) measurements.

PARTICIPANTS

The studies included exposed cement production workers and non-exposed or low-exposed referents.

PRIMARY AND SECONDARY OUTCOMES

The searches yielded 594 references, and 26 articles were included. Cross-sectional studies show reduced lung function levels at or above 4.5 mg/m³ of total dust and 2.2 mg/m³ of respiratory dust. ORs for symptoms ranged from 1.2 to 4.8, while FEV₁/FVC was 1-6% lower in exposed than in controls. Cohort studies reported a high yearly decline in FEV₁/FVC ranging from 0.8% to 1.7% for exposed workers. 1 longitudinal study reported airflow limitation at levels of exposure comparable to ∼1 mg/m³ respirable and 3.7-5.4 mg/m³ total dust. A dose-response relationship between exposure and decline in lung function has only been shown in 1 cohort. 2 studies have detected small increases in FeNO levels during a work shift; 1 study reported signs of airway inflammation in induced sputum, whereas another did not detect an increase in hospitalisation rates.

CONCLUSIONS

Lack of power, adjustment for possible confounders and other methodological issues are limitations of many of the included studies. Hence, no firm conclusions can be drawn. There are few longitudinal data, but recent studies report a dose-response relationship between cement production dust exposure and declining lung function indicating a causal relationship, and underlining the need to reduce exposure among workers in this industry.

Lung function and dust in climbing halls: two pilot studies

In climbing halls, high levels of dust are found because magnesia powder is used to dry hands. Concerns have been raised about possible health effects after reports from asthmatics experiencing worsening of symptoms while or after climbing. We investigated acute and sub-acute effects of climbing in dusty halls on lung function in two pilot studies. The first study examined 109 climbers before and after a climbing activity that lasted at least 1 h. In the second study, 25 climbers from different age classes participated in a 2-day climbing competition. Of these, 24 agreed to take part in our investigation, but only 22 provided valid lung function tests on both days. The climbers underwent lung function tests before the first round of the competition (in the morning), after the second round approximately 3 h later and in the morning of the second day before the competition started again. In the first study, we found acute effects, a decline in lung function immediately after the exposure, likely due to protective reflexes of the bronchial muscles and stronger declines in persons with higher exhaled nitric oxide (NO) pre-climbing. In the second study, we also expected sub-acute effects on the next day due to inflammation. On the first day of the competition (second study), dust levels at a central monitor increased over time in a linear manner. Most of the dust was in the size range between 2.5 and 10 μm and dust levels of particulate matter (PM10) reached 0.5 mg/m3. There was a decline in lung function over 24 h in persons with higher exhaled NO levels pre-exposure. All spirometric parameters were affected though the effects were not statistically significant in all cases. Younger age classes started earlier in the morning. Because of the increasing trend in dust levels we expected stronger effects with higher numbers but for the acute effects the reverse was true, possibly because younger climbers use magnesia more or with less experience thus causing higher individual exposure. No differences by age or by time of the first climb were observed for the 24-h lung function change.

The impact of reduced dust exposure on respiratory health among cement workers: an ecological study

OBJECTIVES

To compare total dust exposure, prevalence of chronic respiratory symptoms, lung function, and chronic obstructive pulmonary disease (COPD) among Tanzanian cement workers before (2002) and after (2010-2011) establishment of dust-control measures.

METHODS

Personal total dust-exposure measurements, questionnaire assessment for chronic respiratory symptoms, and spirometry were conducted in both examination periods.

RESULTS

Total dust exposure was lower in 2010-2011 than in 2002. The prevalence of most chronic respiratory symptoms and COPD was lower in 2010 than in 2002. Forced expiratory volume in 1 second (FEV1), percentage predicted FEV1, and percentage predicted forced vital capacity were higher among cement workers in 2010 than in 2002.

CONCLUSIONS

There was reduced total dust exposure level, lower prevalence of chronic respiratory symptoms and COPD, and higher lung function among cement workers in 2010 than in 2002.

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/m(3) (range 0.02-6.2 mg/m(3)). FEV(1), FEF(25-75%) and DL(CO) 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 0.6×10(9) 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/m(3). 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.

Work-related respiratory symptoms and ventilatory disorders among employees of a cement industry in Shiraz, Iran

Although the main hazard in cement processing is dust and respiratory tract disorders are the most important group of occupational diseases in this industry, evidence for associations between exposure to cement dust and either respiratory symptoms or functional impairment has not been conclusive. This study was, therefore, undertaken to more thoroughly examine the effects of occupational exposure to cement dust on the respiratory system. The study population consisted of a group of 88, randomly selected, male workers with current exposure to cement dust and 80 healthy male office workers without present or past history of exposure to dust that served as the referent group. Subjects were interviewed and were given respiratory symptom questionnaires to answer. They also underwent chest X-ray and lung function tests. Additionally, personal dust monitoring for airborne inhalable and respirable dust was carried out at nine different worksites. Moreover, X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques were performed to determine the silica phases and the SiO2 contents of the dust samples. Levels of exposures to inhalable and respirable cement dust were estimated to be 53.4+/-42.6 and 26+/-14.2 mg/m3, respectively (Mean+/-SD). Statistical analysis of the data revealed that symptoms like regular cough, phlegm, wheezing and shortness of breath were significantly (p<0.05) more prevalent among exposed workers. Similarly, chest radiographs of exposed workers showed various degrees of abnormalities including emphysematous changes, old calcified granulomas, emphysematous changes associated with inflammatory processes, evidence of chronic inflammatory processes, focusal calcification of the lungs and infiltrative changes. However, no significant changes were noted in the radiographs of the referent group. Furthermore, exposed workers compared to their referent counterparts showed significant reductions in the parameters of lung function. In conclusions, our data provide corroborative evidence further substantiating the contention that exposure to cement dust is associated with respiratory symptoms and functional impairments.

Acute respiratory health effects among cement factory workers in Tanzania: an evaluation of a simple health surveillance tool

OBJECTIVES

The effects of cement dust exposure on acute respiratory health were assessed among 51 high exposed and 33 low exposed male cement workers. The ability of the questionnaire to diagnose acute decrease in ventilatory function was also assessed.

METHODS

Acute respiratory symptoms were recorded by interview using a structured optimal symptom score questionnaire. Peak expiratory flow (PEF) was measured preshift and postshift for each worker with a Mini-Wright PEF meter. Personal respirable dust (n=30) and total dust (n=15) were measured with 37-mm Cyclone and 37-mm closed-faced Millipore cassette. Twenty-nine workers had concurrent respirable dust, PEF and questionnaire on the same day.

RESULTS

The geometric means of personal respirable dust and total dust among high exposed were 4.0 and 13.2 mg/m(3), respectively, and 0.7 and 1.0 mg/m(3) among low exposed. High exposed workers had more acute cough, shortness of breath and stuffy nose than the low exposed. Mean percentage cross-shift decrease in PEF was significantly more pronounced among high exposed workers than low exposed (95% CI 1.1, 6.1%). For workers with concurrent respirable dust, PEF and questionnaire assessment, an exposure-response relationship was found between log-transformed respirable dust and percentage cross-shift decrease in PEF (4.5% per unit of log-respirable dust in mg/m(3) ; 95% CI 3.3, 5.6%). Respirable dust exposure >/=2.0 mg/m(3) versus <2.0 mg/m(3) was associated with increased prevalence ratio for cough (7.9) and shortness of breath (4.2). Shortness of breath was associated with the highest sensitivity (0.87) and specificity (0.83) for diagnosing a percentage cross-shift decrease in PEF of >/=10%.

CONCLUSION

The observed acute respiratory health effects among the workers are most likely due to exposure to high concentrations of irritant cement dust. The results also highlight the usefulness of the questionnaire for health surveillance of the acute respiratory health effect.

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/m year versus lower than 100 mg/m 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/m) appears to be too high to prevent respiratory health effects among cement workers.

Respiratory symptoms and ventilatory function in workers exposed to portland cement dust

The healthy worker effect and incomplete exposure information have been problems in former studies regarding the association between exposure to Portland cement dust and respiratory effects. We included former workers and made an individual estimation of particle exposure to reduce the selection bias in this controlled cross-sectional study on the effects of cement dust exposure on respiratory symptoms and ventilatory function in long-term exposed Norwegian cement plant workers. A total of 119 workers from the largest cement plant in Norway and 50 workers from a nearby control plant, born 1918 to 1938, performed spirometry and gave information on respiratory symptoms in 1998 and 1999. The prevalence of symptoms and mean pulmonary function indices were similar for exposed workers and controls. There was no dose-response-related increase in symptoms or decrease in lung function indices. The estimated power to detect a true difference between forced expiratory volume in one second (FEV1) in the two groups of 0.3l was 0.90, assuming 95% significance level. The prevalence of chronic obstructive pulmonary disease was 14.3% in the exposed group and 14.0% among the controls. These findings do not support the hypothesis that cement dust exposure has a negative impact on lung function or gives an increase in respiratory symptoms.