In industrial workers,
formaldehyde exposure has been associated with
cancer of the nasal cavities, nasopharynx, prostate, lung, and pancreas; however, these associations are inconsistent and remain controversial. Animals exposed to
formaldehyde show excesses of
nasal cancer. In an extended follow-up of a large cohort of
formaldehyde-exposed workers, the authors evaluated mortality from solid
cancers (1,921 deaths) among 25,619 workers (865,708 person-years) employed in 10 US
formaldehyde-producing or -using facilities through 1994. Exposure assessment included quantitative estimates of
formaldehyde exposure. Standardized mortality ratios and relative risks were calculated. Compared with that for the US population, mortality from solid
cancers was significantly lower than expected among subjects exposed and nonexposed to
formaldehyde (standardized mortality ratios = 0.91 and 0.78, respectively). Relative risks for
nasopharyngeal cancer (nine deaths) increased with average exposure intensity, cumulative exposure, highest peak exposure, and duration of exposure to
formaldehyde (p-trend = 0.066, 0.025, <0.001, and 0.147, respectively).
Formaldehyde exposure did not appear to be associated with lung (744 deaths), pancreas (93 deaths), or brain (62 deaths)
cancer. Although relative risks for
prostate cancer (145 deaths) were elevated for some measures of
formaldehyde exposure, the trend was inconsistent. In this cohort of
formaldehyde-industry workers, some evidence was found of an exposure-response relation with mortality from
nasopharyngeal cancer (based on small numbers) but not for
cancers of the pancreas, brain, lung, or prostate.