Cancer morbidity and quartz exposure in Swedish iron foundries.
OBJECTIVE
The aim of this study was to determine cancer morbidity amongst Swedish iron foundry workers with special reference to quartz exposure. In addition to respirable dust and quartz, phenol, formaldehyde, furfuryl alcohols, polycyclic aromatic hydrocarbons (PAHs), carbon black, isocyanates and asbestos are used or generated by foundry production techniques and exposure to any of these substances could have potentially carcinogenic effects.


METHODS
Cancer morbidity between 1958 and 2004 was evaluated in a cohort of 3,045 male foundry workers employed for >1 year between 1913 and 2005. Standardised incidence ratios (SIRs) with 95 % confidence intervals (95 % CI) were determined by comparing observed numbers of incident cancers with frequencies in the Swedish cancer register. Exposure measures were assessed using information from the personal files of employees and modelling quartz measurement based on a database of 1,667 quartz measurements. Dose responses for lung cancer were determined for duration of employment and cumulative quartz exposure for latency periods >20 years.


RESULTS
Overall cancer morbidity was not increased amongst the foundry workers (SIR 1.00; 95 % CI, 0.90-1.11), but the incidence of lung cancer was significantly elevated (SIR 1.61; 95 % CI, 1.20-2.12). A non-significant negative dose response was determined using external comparison with a latency period of >20 years (SIR 2.05, 1.72 1.26 for the low, medium and high exposure groups), supported by internal comparison data (hazard ratios 1, 1.01, 0.78) for the corresponding groups. For cancers at sites with at least five observed cases and a SIR > 1.25, non-significant risks with SIRs > 1.5 were determined for cancers of the liver, larynx, testis, connective muscle tissue, multiple myeloma plasmacytoma and lymphatic leukaemia.


CONCLUSIONS
A significant overall risk of lung cancer was determined, but using external and internal comparison groups could not confirm any dose response at our cumulative quartz dose levels.
Department of Occupational and Environmental Medicine, Örebro University Hospital, 701 85, Örebro, Sweden.
Håkan
H
Westberg
Lena
L
Andersson
Ing-Liss
IL
Bryngelsson
Yen
Y
Ngo
Carl-Göran
CG
Ohlson
D000395:Air Pollutants, Occupational / Q000009:adverse effects* / Q000032:analysis; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007501:Iron; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000453:epidemiology / Q000209:etiology; D008297:Male; D008669:Metallurgy; D015233:Models, Statistical; D009369:Neoplasms / Q000453:epidemiology / Q000209:etiology*; D009784:Occupational Diseases / Q000453:epidemiology / Q000209:etiology*; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D011791:Quartz / Q000009:adverse effects* / Q000032:analysis; D012042:Registries; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors
D000395:Air Pollutants, Occupational; D011791:Quartz; D007501:Iron