International Agency for Research on Cancer (IARC) - Summaries & Evaluations


VOL.: 25 (1981) (p. 157)

5. Summary of Data Reported and Evaluation

5.1 Summary of data

Information on the cancer experience of paper and pulp mill workers is limited. Most of the studies that assess risk are based on reviews of death certificate information on occupation; few studies had occupational histories or information on potentially influential variables such as cigarette smoking, and none followed the cancer mortality or morbidity of a large cohort of workers.

A case-control study in New York state of death certificates of Hodgkin's disease showed a four-fold excess of this cancer associated with employment in the paper industry. A similar study in Washington state subsequently showed a two-fold increase of Hodgkin's disease, as well as smaller, but significant increases for other lymphomas, but not for leukaemia. Elevated lymphoma risks were also reported for both operatives and labourers in the paper and allied products industry in a large multi-tumour-site case-control study in New York state.

Lung cancer mortality rates among males were elevated in eastern, but not western, US counties with paper or pulp mills. Death certificate surveys of occupation likewise show inconsistent results, with significant increases among paper workers in three studies: one in the south-east US where an excess was seen in rural, but not urban areas, although workers were employed in industries in both areas; the second in a cross-sectional study where occupational data were missing for one-third of the cases; and the third in which a small increase was seen in a national survey of deaths by occupation throughout the US. Increases were not seen in two other studies, nor in a detailed interview survey in which occupational histories and information on cigarette smoking were obtained.

A large, multi-tumour-site case-control study in New York state reported a four-fold excess of laryngeal cancer linked to five or more years' employment in the paper industry; and a 50% elevated ratio for this cancer was observed among paper workers in the Washington state mortality statistics. Both studies involved small numbers of cases among paper workers: five and six, respectively. A four-fold excess of oral and pharyngeal cancer was also seen in the New York study; and in US counties with paper or pulp manufacturing industries there tended to be slightly elevated rates of oral and pharyngeal cancer mortality among males.

The description of the industrial processes shows that some of the chemicals used are those for which there is evidence of carcinogenicity in humans and/or experimental animals (see Appendix 4, in this volume). Although some of these chemicals are no longer used, others are still in use. The introduction of chlorination for treatment of effluents from pulping processes may cause transformation of molecular species to form carcinogenic and/or mutagenic chemicals.

5.2 Evaluation

The epidemiological data are not sufficient to make a definitive assessment of the carcinogenic risk of employment in the paper or pulp mill industries. Several studies suggest that an increased risk of lymphoproliferative neoplasms, particularly Hodgkin's disease and perhaps leukaemia, may be linked to employment in the paper and pulp industries.

Excesses of oral and pharyngeal and of laryngeal cancers were reported in two studies designed to generate hypotheses, and have not been evaluated in independent studies. There appears to be no moderate or large overall increased risk of lung cancer among paper workers. The excess risk of lung cancer observed in some subgroups of workers in two of the studies cannot be evaluated.

Subsequent evaluation: Suppl. 7 (1987)

Last updated: 8 April 1998

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