Lung function in asphalt pavers: a longitudinal study.

PURPOSE: To study longitudinal changes in lung function in asphalt pavers and a reference group of road maintenance workers, and to detect possible signs of lung disease by high-resolution computed tomography (HRCT) scans. METHODS: Seventy-five asphalt pavers and 71 road maintenance workers were followed up with questionnaires and measurements of lung function. Not every worker was tested every year, but most of them had four or more measurement points. The 75 asphalt pavers were also invited to have HRCT scans of the lungs at the end of the follow-up period. RESULTS: Mean annual decline in forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) of the asphalt pavers was 58 and 35 ml, respectively. Adjusted for age at baseline, packyears of smoking and BMI, the asphalt pavers had a significant excess annual decline in FVC and FEV1 compared to the references. The screedmen, the most exposed group of the asphalt pavers, showed a significantly larger decline in FVC than the other asphalt pavers (P = 0.029). Fine intralobular fibrosis without evident cysts was identified with HRCT in three subjects (4 %). CONCLUSION: We conclude that our findings may indicate an excess annual decline in FVC and FEV1 related to exposure to asphalt fumes. The screedmen, who carry out their work behind and close to the paving machine, had the largest decline in lung function. The finding of adverse pulmonary effects in asphalt pavers calls for better technological solutions to prevent exposure.

Exposure to ultrafine particles in asphalt work.

An epidemiologic study has demonstrated that asphalt workers show increased loss of lung function and an increase of biomarkers of inflammation over the asphalt paving season. The aim of this study was to investigate which possible agent(s) causes the inflammatory reaction, with emphasis on ultrafine particles. The workers' exposure to total dust, polycyclic aromatic hydrocarbons, and NO(2) was determined by personal sampling. Exposure to ultrafine particles was measured by means of particle counters and scanning mobility particle sizer mounted on a van following the paving machine. The fractions of organic and elemental carbon were determined. Asphalt paving workers were exposed to ultrafine particles with medium concentration of about 3.4 x 10(4)/cm(3). Ultrafine particles at the paving site originated mainly from asphalt paving activities and traffic exhaust; most seemed to originate from asphalt fumes. Oil mist exceeded occupational limits on some occasions. Diesel particulate matter was measured as elemental carbon, which was low, around 3 microg/m(3). NO(2) and total dust did not exceed limits. Asphalt pavers were exposed to relatively high concentrations of ultrafine particles throughout their working day, with possible adverse health effects.

Clara cell protein as a biomarker for lung epithelial injury in asphalt workers.

OBJECTIVE: We investigated if asphalt workers showed signs of lung epithelial injury as shown by increased Clara cell protein 16 (CC16) in serum after 6 months of exposure. METHODS: Asphalt pavers, asphalt plant operators, and asphalt engineers underwent lung function tests and blood samples before the start of the asphalt season. The tests were repeated before the end of the asphalt season. Blood samples were analyzed for concentration of CC16 and interleukin-6 (IL-6). RESULTS: After adjustment for current smoking, the pavers had a significantly larger increase in CC16 concentrations after the season as compared with that of the engineers and plant operators. In pavers, the change in serum CC16 was correlated with the change in IL-6. CONCLUSION: CC16 increased over the season in pavers and appears to be a useful biomarker for lung epithelial injury in exposed workers.

Exposure, lung function decline and systemic inflammatory response in asphalt workers.

OBJECTIVES: The aim of this study was to determine the association between exposures in asphalt work and changes in lung function, blood concentrations of interleukin-6 (IL-6), micro-C-reactive protein, and fibrinogen among asphalt workers during a work season. METHODS: Blood samples from all asphalt workers (N=140) in Norway's largest road construction and maintenance company were taken in April-May 2005 and again in September-October 2005. Spirometric tests of the asphalt workers and a reference group (heavy construction workers, N=126) were carried out before the asphalt season, and the asphalt workers were tested again at the end of the season. Exposure to total dust, oil mist, polycyclic aromatic hydrocarbons, and gases was measured by personal samplers during the asphalt season. RESULTS: The asphalt workers had a significantly a lower forced expiratory volume in 1 second (FEV(1)) and forced expiratory flow rate of 50% of the forced vital capacity than the reference group at the beginning of the season. The asphalt workers were divided according to their exposure into two groups, asphalt pavers (N=81) and asphalt plant operators and truck drivers (N=54). The screedmen, a group of the asphalt pavers, had a statistically significant lower FVC and FEV(1) after one season of asphalt work than all of the other asphalt workers (P<0.05). The mean plasma concentration of IL-6 increased among the asphalt pavers from 1.55 pg/ml before the season to 2.67 pg/ml at the season's end (P=0.04, adjusted for current smoking). CONCLUSIONS: Exposure in asphalt paving may enhance the risk of lung function decline.

Cancer incidence of Nordic asphalt workers.

OBJECTIVES: The aim of the study was to investigate cancer risk following employment in the asphalt industry. METHODS: Cancer incidence was studied among 22 362 male asphalt workers employed for more than one season in jobs entailing exposure to bitumen (mainly road pavers) in Denmark, Finland, Norway, and Sweden. These workers are part of a European cohort of asphalt workers, for which results on mortality have been reported. The follow-up was almost complete, and reference rates were obtained from national cancer registries. RESULTS: The incidence of cancer was reduced in all four countries [overall standardized incidence ratio (SIR) 0.89, 95% confidence interval (95% CI) 0.86-0.94]. Lung cancer incidence was increased in all four countries, yielding an overall SIR of 1.21 (95% CI 1.07-1.36), but no trend was detected according to time since first employment. No overall increased incidence of bladder cancer was observed, but there was a suggestion of a tendency towards higher risk with longer time since first employment, with a relative risk of 1.85 (95% CI 0.90-3.78) for more than 30 years versus 1-14 years (P-value for trend 0.1). The incidence of lip and stomach cancer was nonsignificantly increased, and the excess was present mainly in Denmark. No increased incidence was detected for other neoplasms, notably malignant melanoma, nonmelanoma skin cancer, and kidney cancer. CONCLUSIONS: The results of this study confirm the pattern of cancer risk detected in the mortality analysis of the European cohort; in addition, they provide suggestive evidence of an excess risk of bladder cancer among asphalt workers.

Cancer incidence among male Norwegian asphalt workers.

BACKGROUND: The main objective of the present study was to investigate whether exposure to bitumen fumes could enhance the risk of cancer in asphalt workers. METHODS: A historical prospective cohort study was performed including 8,763 male asphalt workers from all main asphalt companies in Norway. Name, date of birth, and unique personal identification number, address, job type, and start and stop of employment in specific jobs was obtained for the workers. Information was complied from payroll and personnel records in the companies. The cohort was then linked to the Cancer Registry of Norway, which has complete records of individual cases of cancer in the Norwegian population since 1953. Follow-up was from 1 January 1970 to 31 December 1997. The 5-year age and period adjusted general male population in Norway served as reference population. RESULTS: Lung cancer was found elevated with standardized incidence ratio (SIR) = 1.3 (95% confidence intervals (CI) = 1.1, 1.7) in the overall analysis. Lung cancer was found more elevated in workers first exposed in the 1950s and 1960s and in mastic asphalt workers (SIR = 4.2, 95% CI = 1.2, 10, based on four cases) and pavers (SIR = 1.4, 95% CI = 1.0, 1.9). There was a deficiency in the incidence of malignant melanoma with 13 cases versus 26 expected. CONCLUSIONS: Risk of lung cancer was found enhanced among the asphalt workers. Some of the enhanced risk could probably be explained by the smoking habits of the workers. Exposure to coal tar may also have contributed to the enhanced risk.

Mortality from non-malignant diseases among male Norwegian asphalt workers.

BACKGROUND: The possible associations between asphalt work and mortality from non-malignant diseases in a cohort of male Norwegian asphalt workers that formed part of the European asphalt worker mortality study are examined. METHODS: The mortality experience among 8,610 male workers ever employed in asphalt work was observed from 01.01.1970 until 12.31.1996, yielding 127,636 person years of observation. The cause-specific deaths observed in the study cohort were compared with the expected figures calculated from 5-year period- and age-specific national death rates. A study-specific job exposure matrix was used for individual-individual exposure estimates. RESULTS: Eight hundred and three workers died during the observation period (SMR = 0.92, 95% confidence intervals (CI) = 0.58, 1.40). The mortality from non-malignant respiratory diseases was elevated (SMR = 1.25, 95%CI = 0.97, 1.58) and was associated with years since first employment in the asphalt industry. Mortality from respiratory diseases was highest among the workers first employed in the 1960s. Among the different job types held by the workers the pavers and mastic asphalt workers had the highest mortality from respiratory diseases. A weak dose-response was found with cumulative exposure to PAH and bitumen fume and mortality from non-malignant respiratory diseases in analyses employing the job-exposure matrix. Overall mortality, the mortality from circulatory diseases (SMR = 0.93, 95%CI = 0.83, 1.03) and external causes (SMR = 0.90, 95%CI = 0.72, 1.11) was lower than expected. CONCLUSIONS: Mortality from respiratory diseases was found somewhat elevated among the asphalt workers. There was some evidence of exposure-response with both bitumen fume and PAH exposure. PAH from coal tar contributes to the PAH exposure.