Nasopharyngeal cancer, sinonasal cancer, and occupations related to formaldehyde: a case-control study.
A case comparison study of nasopharyngeal cancer, sinonasal cancer, and occupations related to exposure to formaldehyde (50000) (FA) was conducted through the Connecticut Tumor Registry (CTR) and the Connecticut Division of Health Statistics. Cases were limited to males, resident in Connecticut at time of death, who were registered with a diagnosis of sinonasal cancer (SNC) or nasopharyngeal cancer (NPC) by the CTR and who died in the period 1935 to 1975. Subjects' occupations were determined at 1, 10, 20, 25, 30, 40, and 50 years prior to death or until the subject was under the age of 20. Distribution of SNC and NPC and comparison subjects (CS) was summarized according to four degrees of FA exposure. Among 16 subjects classified by exposure criterion IV (probably exposed to some level for most of working life and probably exposed to high level at 20+ years prior to death), 6 died of NPC, an odds ratio of 2.3; for the 10 CS with the same risk factor and dying at 68 years of age or more, the odds ratio was 4.0. Possible exposure of cases and CS to FA and adjusted odds ratios for any nasal cancer across occupation categories were summarized. No increased risks were observed for those exposed to FA and employed in the textile, metal, agriculture, and wood industries or as barbers and painters; however, FA exposure was associated with NPC or SNC in those employed in printing. In noting the coincidence of anatomic site, latency, and age, the authors speculate that the greater risk for NPC in the older men may be due to lower risk for cancer from genetic, dietary, or infectious agents; they recommend further study to clarify the role of FA in carcinogenesis.