Occupational Formaldehyde Exposure And Risk Of Cancer At Selected Sites

Kristina KJAERHEIM, Cancer REgistry of Norway, Norway
MARTINSEN J. 1 , PUKKALA E. 2 , MADAR T. 3 , WEIDERPASS E. 1 , GRIMSRUD T. 1

1 Department of Research, Cancer Registry of Norway, Oslo, Norway
2 Finnish Cancer Registry, Helsinki, Finland
3 School of Public Health, University of Tampere, Finland
4 Karolinska Institute, Stockholm, Sweden

PURPOSE
To investigate risk of lymphohaematopoietic (LH), sino-nasal, and epipharyngeal cancers according to cumulative formaldehyde exposure.
METHODS
A cohort comprising more than 300 000 men from Finland and Sweden in 25 occupations identified as formaldehyde exposed was extracted from the Nordic Occupational Cancer Study (NOCCA). LH cancers were analyzed using partly overlapping categories. During follow-up from 1961–2003 in Sweden and 1970–2005 in Finland, altogether 7495 LH, 164 epipharyngeal, and 321 sino-nasal cancer cases were observed. Five controls per case were matched by age and country, and hazard ratios (HRs) were computed according to cumulative formaldehyde exposure with adjustment for relevant potential confounders (benzene, wood dust, nickel, and chromium). Exposure estimates were based on information of probability and level of exposure from the NOCCA Job Exposure Matrix.
 
RESULTS
For leukaemia, non-Hodgkin lymphoma (NHL), and multiple myeloma (MM), non-significant increases ranging from 9 to 23% were seen among the 10% with highest cumulative exposure. No association with exposure was seen for AML, but for CLL a borderline statistically significant risk elevation was observed (HR 1.29, 95% confidence interval [CI] 0.98-1.69). When a 10-year exposure lag was applied, HR for CLL was 1.37 (CI 1.04-1.82). Combining CLL, NHL and MM in the analyses, in accordance with newer classification schemes, we found a significant elevation of 11% (CI 1.00-1.23), increasing to 17% with a 10-year exposure lag (CI 1.04-1.32). For sino-nasal cancer, risk was significantly elevated only in the lagged analysis (HR 2.00, CI 1.07-3.75). No risk elevation was observed for epipharyngeal cancer.
 
CONCLUSIONS
Formaldehyde exposure appears to affect more LH cancer types than leukemia. The association with leukaemia was driven mainly by CLL. Sino-nasal cancer risk was doubled in the highest exposure group.
 
Funding sources
Nordic Cancer Union