Authors: Marsh, Gary M., Peter Morfeld, Sarah D. Zimmerman, Yimeng Liu, and Lauren C. Balmert.
The reanalysis provided little or no evidence to support NCI's suggestion of a persistent association between formaldehyde exposure and mortality from nasopharyngeal cancer. Specifically, the findings led to: (1) reduced standardized mortality ratios and relative risks in the remaining nine study plants in unaffected exposure categories, (2) attenuated exposure-response relations for formaldehyde and nasopharyngeal cancer for all the formaldehyde metrics considered and (3) strengthened and expanded evidence that the earlier NCI internal analyses were non-robust and mis-specified as they did not account for a statistically significant interaction structure between plant group (Plant 1 vs. Plants 2-10) and formaldehyde exposure.