Cancer mortality and wood dust exposure among participants in the American Cancer Society Cancer Prevention Study-II (CPS-II)

Abstract

In 1994, the International Agency for Research on Cancer (IARC) classified wood dust as a human carcinogen, based on very strong evidence of a carcinogenic risk of sino‐nasal cancer. Excesses of other cancers, including lung and stomach, have been reported among persons employed in wood industries or occupationally exposed to wood dust, but not as consistently. We investigated such possible associations using the mortality experience of 362,823 men enrolled in the American Cancer Society's Cancer Prevention Study — II in 1982 and followed up for 6 years. Within this group, 45,399 men (12.5%) reported either employment in a wood‐related occupation or exposure to wood dust or both. Among woodworkers, a small but significant excess risk was found for all causes of death (RR 1.17 (95% CI 1.11–1.24)) and for total malignancies (RR 1.17 (1.05–1.30)). Among men who reported exposure to wood dust, there was an elevated risk of total mortality (RR 1.07 (1.03–1.11)), total malignancies (RR 1.08 (1.01—1.15)), and lung cancer (RR 1.17 (1.04–1.31)). Among woodworkers, a significant trend (P = 0.02) of increasing risk of lung cancer with increasing duration of exposure was observed. An unexpected, significantly increased mortality from prostate cancer was observed in both wood‐employed and wood‐exposed, and a twofold increased risk of fatal brain cancer was seen among the former. Lung cancer mortality was especially high among woodworkers who also reported exposure to asbestos or formaldehyde, and it appears that exposure to these known carcinogens may partly explain the observed increased risks. Excess sino‐nasal cancer was not observed, but the number of cases was small. Am. J. Ind. Med. 34:229–237, 1998. © 1998 Wiley‐Liss, Inc.

Assessment of the effect of occupational exposure to formaldehyde on the risk of lung cancer in two Canadian population-based case–control studies

“…Findings from these studies did not strongly support an effect of formaldehyde on lung cancer risk. Statistically significant positive associations were observed in only 2 of the 14 cohort studies (2, 6 -19): in the subgroup of wood-related workers from a general US population cohort (11) and a large occupational cohort of British workers (10). For three cohorts, results showed positive associations although not statistically Mahboubi et al which subgroups defined by smoking status were examined (6,23) where differences in the formaldehyde-lung cancer associations were not apparent.…”

“…The Report on Carcinogens Background Document for Formaldehyde from the US National Toxicology Program (1) considered 23 studies that reported on the association between exposure to formaldehyde and lung cancer risk (2,. Overall, these studies generated equivocal results, with small increases in risk observed in some studies (6, 9-13, 22-24, 27), though reaching statistical significance only in four (10,11,24,27). A wide variety of exposure assessment methods and combinations thereof were used to assess individual exposure to formaldehyde.…”

“…Some of the older studies used job title (often embalmers or pathologists) as a proxy for exposure (8, 14-17, 19, 21) or a more elaborate job exposure matrix (JEM) but focused on the last job held as indicated on the death certificate (27). Other methods included the use of (i) employment records (2,6,7,9,10,12,13,18,22,25,26), (ii) a JEM, (iii) industrial hygiene data (2,6,10,18,22,23,25,26), or (iv) selfreport of exposure to formaldehyde (11,20,24) or occupational history (23,28). Information on smoking, a key potential confounder, was available and accounted for in the analyses in only seven studies (6,11,20,22,24,25,28), some of which had large proportions of missing values for smoking variables.…”

“…Information on smoking, a key potential confounder, was available and accounted for in the analyses in only seven studies (6,11,20,22,24,25,28), some of which had large proportions of missing values for smoking variables. Similarly, few studies had information on exposure to other occupational lung carcinogens that may be correlated with formaldehyde exposure (2,6,11,22,28). In addition, only six studies (2,13,16,20,21,29) included women in their study population, though analyses by gender were reported in only three studies (13,16,20).…”

International issues on human health effects of exposure to chemical mixtures.

“…On the other hand, a recent survey carried out in the United States has thrown doubt on the significance of wood dust as a human carcinogen. Among men who reported exposure to wood dust, there was an elevated risk of total mortality but no excess of sinonasal cancer (98).…”