Blood markers of inflammation and coagulation and exposure to airborne particles in employees in the Stockholm underground.
OBJECTIVE
Although associations have been found between levels of ambient airborne particles and cardiovascular disease (CVD) in the general population, little is known about possible cardiovascular effects from high exposure to particles in underground railway systems. This study investigates risk markers for CVD in employees exposed to particles in the Stockholm underground system.


METHODS
79 workers (54 men and 25 women) in the Stockholm underground were investigated between November 2004 and March 2005. All were non-smokers aged 25-50 years. Three exposure groups were delineated: 29 platform workers with high exposure to particles, 29 train drivers with medium exposure and 21 ticket sellers with low exposure (control group). A baseline blood sample was taken after 2 non-working days, and a second sample after 2 working days, for analysis of levels of plasminogen activator inhibitor-1 (PAI-1), high-sensitivity C-reactive protein (hs-CRP), interleukin-6, fibrinogen, von Willebrand factor and factor VII. The study investigated changes in plasma concentrations between sample 1 and sample 2, and differences in average concentrations between the groups.


RESULTS
No changes between sample 1 and 2 were found that could be attributed to particle exposure. However, the highly exposed platform workers were found to have higher plasma concentrations of PAI-1 and hs-CRP than the ticket sellers and train drivers. This suggests that particle exposure could have a long-term inflammatory effect. These differences remained for PAI-1 in the comparison between platform workers and ticket sellers after adjusting for body mass index.


CONCLUSIONS
Employees who were highly exposed to airborne particles in the Stockholm underground tended to have elevated levels of risk markers for CVD relative to employees with low exposure. However, the differences observed cannot definitely be linked to particle exposure as such.
Bigert
C
C
Department of Occupational and Environmental Health, Karolinska Institutet, Norrbacka 4th Floor, SE-171 76 Stockholm, Sweden. carolina.bigert@sll.se
Alderling
M
M
Svartengren
M
M
Plato
N
N
de Faire
U
U
Gustavsson
P
P
D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D001779:Blood Coagulation Factors / Q000378:metabolism*; D002097:C-Reactive Protein / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000097:blood / Q000209:etiology*; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D052638:Particulate Matter / Q000633:toxicity*; D011890:Railroads; D013548:Sweden; D017132:Workplace
D015415:Biomarkers; D001779:Blood Coagulation Factors; D015850:Interleukin-6; D052638:Particulate Matter; D002097:C-Reactive Protein