A Nested Case–Control Study of Serum Per- and Polyfluoroalkyl Substances and Testicular Germ Cell Tumors among U.S. Air Force Servicemen
Menée auprès de 530 témoins et 530 militaires de l'US AirForce atteints d'une tumeur germinale du testicule, cette étude analyse l'association entre la concentration sérique en substances per- et polyfluoroalkylées et le risque de développer la maladie
Résumé en anglais
Background: Per- and polyfluoroalkyl substances (PFAS) are a component of firefighting foams used at military installations. Although high PFAS exposures have been related to cancer risks among civilian populations, the effects for military personnel are unclear.
Objectives: We investigated associations between serum PFAS concentrations and testicular germ cell tumors (TGCT) among U.S. Air Force servicemen.
Methods: This nested case–control study involved active-duty Air Force servicemen with sera from the Department of Defense Serum Repository. We selected 530 cases and 530 controls individually matched on birth date, race and ethnicity, year entered the service, and year of sample collection, with prediagnostic serum samples collected between 1988 and 2017. A second prediagnostic sample, collected a median of 4 y after the first, was selected for 187 case–control pairs. Seven PFAS were quantified using isotope-dilution tandem mass spectrometry. Odds ratios (ORs) and 95% confidence intervals (CIs) from conditional logistic regression adjusting for military grade, number of deployments, and, in some models, other PFAS, estimated associations between PFAS concentrations (categorized using quartiles among controls) and TGCT.
Results: Elevated concentrations of some PFAS were observed for military employment in firefighting [perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid] and service at a base with high PFAS concentrations in drinking water (PFHxS). Elevated PFOS concentrations in the second sample were positively associated with TGCT [OR for fourth vs. first quartile open parenthesis odds ratio begin subscript quartile 4 end subscript close parenthesis equals 2.6(ORQ4)=2.6, 95% CI: 1.1, 6.4; lowercase italic p begin subscript trend end subscript equals 0.02ptrend=0.02], including after adjustment for other PFAS (odds ratio begin subscript quartile 4 end subscript equals 4.6ORQ4=4.6, 95% CI: 1.4, 15.1; lowercase italic p begin subscript trend end subscript equals 0:009ptrend=0.009
). Associations with PFOS in the first/only samples were weak and not statistically significant. Elevated concentrations of perfluorononanoic acid were inversely associated with TGCT, whereas results were null for other PFAS.
Discussion: We identified service-related predictors of PFAS concentrations and increased TGCT relative risks with elevated PFOS concentrations among Air Force servicemen. These findings warrant further investigation in other populations and military service branches.
