. 2023 Jul 17;131(7):077007. doi: 10.1289/EHP12603

Table 2.

Least squares geometric mean concentrations of PFOS, PFOA, and PFHxS (ng/mL) in relation to subject and sample characteristics for samples collected after start of military service among active-duty U.S. Air Force servicemen ( $lowercase italic n equals 830$ ).

	First/only sample ( $lowercase italic n equals 830$ )							Second sample ( $lowercase italic n equals 362$ )
		PFOS		PFOA		PFHxS			PFOS		PFOA		PFHxS
	$n$	GM^a (95% CI)	$p$ -Value	GM^a (95% CI)	$p$ -Value	GM^a (95% CI)	$p$ -Value	$n$	GM^a (95% CI)	$p$ -Value	GM^a (95% CI)	$p$ -Value	GM^a (95% CI)	$p$ -Value
Year serum collected
$less than 1996$	33	51.9 (37.5, 71.8)	0.11	7.4 (5.6, 10.0)	0.10	5.5 (3.1, 9.9)	0.008	3	50.2 (27.1, 92.9)	0.73	5.9 (3.6, 9.8)	0.25	4.4 (1.7, 11.5)	0.05
1996–1998	313	60.5 (46.0, 79.6)	—	8.6 (6.7, 11.0)	—	9.8 (6.0, 15.9)	—	34	55.7 (41.0, 75.6)	—	7.9 (6.1, 10.1)	—	11.1 (6.9, 17.8)	—
1999–2004	264	52.7 (39.9, 69.7)	0.002	9.6 (7.4, 12.3)	0.007	9.4 (5.7, 15.4)	0.64	136	43.4 (32.9, 57.3)	0.009	8.2 (6.6, 10.3)	0.56	9.0 (5.8, 13.8)	0.15
$greater than or equal to 2005$	220	23.0 (17.3, 30.5)	$less than 0.001$	5.4 (4.2, 6.9)	$less than 0.001$	7.6 (4.6, 12.6)	0.01	189	19.2 (14.7, 25.2)	$less than 0.001$	5.3 (4.2, 6.6)	$less than 0.001$	5.8 (3.8, 8.9)	$less than 0.001$
Age (y) at serum collection
$less than 20$	173	37.7 (28.0, 50.7)	0.20	6.7 (5.1, 8.7)	0.02	5.7 (3.4, 9.7)	0.16	15	36.8 (25.2, 53.7)	0.72	5.7 (4.2, 7.8)	0.35	7.5 (4.1, 13.5)	0.37
20–24	301	40.3 (30.4, 53.4)	—	7.4 (5.8, 9.6)	—	6.5 (3.9, 10.7)	—	114	34.8 (25.3, 47.8)	—	6.5 (5.0, 8.4)	—	6.0 (3.7, 9.9)	—
25–29	160	44.2 (33.3, 58.8)	0.11	7.8 (6.0, 10.0)	0.40	8.1 (4.9, 13.4)	0.03	109	37.9 (27.5, 52.2)	0.32	7.3 (5.6, 9.5)	0.09	6.7 (4.0, 11.0)	0.46
30–34	126	50.5 (37.7, 67.7)	0.004	8.3 (6.4, 10.8)	0.12	9.8 (5.8, 16.5)	0.003	87	38.5 (27.7, 53.5)	0.33	7.0 (5.3, 9.1)	0.39	6.6 (3.9, 11.0)	0.59
$greater than or equal to 35$	70	49.4 (36.5, 67.0)	0.03	7.8 (5.9, 10.2)	0.61	10.4 (6.0, 17.8)	0.005	37	48.9 (34.4, 69.6)	0.005	7.2 (5.4, 9.7)	0.26	9.1 (5.2, 15.8)	0.03
Race and ethnicity
Non-Hispanic White	658	44.8 (34.0, 59.0)	—	8.0 (6.2, 10.2)	—	8.4 (5.2, 13.7)	—	284	42.2 (31.5, 56.5)	—	7.4 (5.8, 9.4)	—	8.3 (5.3, 13.2)	—
Other	172	43.5 (32.8, 57.7)	0.49	7.2 (5.6, 9.3)	0.009	7.4 (4.5, 12.2)	0.08	78	36.2 (26.4, 49.6)	0.02	6.1 (4.7, 7.9)	0.0002	6.0 (3.7, 9.8)	0.001
Education
$\leq High school$	387	44.1 (34.0, 57.1)	—	7.5 (6.0, 9.5)	—	10.2 (6.4, 16.1)	—	159	42.2 (30.3, 58.7)	—	7.1 (5.4, 9.3)	—	7.4 (4.4, 12.4)	—
Some college	200	44.7 (34.5, 58.0)	0.76	7.2 (5.7, 9.1)	0.30	9.7 (6.1, 15.4)	0.61	105	38.5 (27.6, 53.8)	0.14	6.6 (5.0, 8.6)	0.12	6.9 (4.1, 11.7)	0.50
Bachelor’s degree	117	39.0 (30.4, 50.1)	0.12	6.6 (5.3, 8.3)	0.07	8.0 (5.1, 12.5)	0.09	35	39.5 (28.5, 54.8)	0.58	6.9 (5.3, 9.0)	0.74	7.2 (4.3, 12.0)	0.87
Advanced degree	124	40.1 (31.1, 51.7)	0.32	7.0 (5.5, 8.8)	0.37	7.3 (4.6, 11.4)	0.05	63	36.4 (26.5, 49.9)	0.25	6.3 (4.9, 8.2)	0.27	6.8 (4.2, 11.2)	0.69
Grade
E01–10 (Enlisted)	633	44.2 (33.6, 58.3)	—	7.6 (6.0, 9.8)	—	7.4 (4.6, 12.2)	—	284	40.7 (29.9, 55.3)	—	7.0 (5.4, 8.9)	—	7.3 (4.5, 11.7)	—
O1–O10 (Officer)	197	44.1 (32.7, 59.4)	0.96	7.5 (5.7, 9.8)	0.82	8.4 (4.9, 14.2)	0.43	78	37.6 (27.1, 52.2)	0.50	6.5 (5.0, 8.5)	0.46	6.9 (4.1, 11.6)	0.79
Years of service at serum collection
$less than 1$	403	40.3 (30.3, 53.5)	—	7.6 (5.9, 9.8)	—	7.2 (4.4, 12.0)	—	17	37.3 (25.1, 55.4)	—	6.7 (4.8, 9.2)	—	5.6 (3.0, 10.4)	—
$1 to less than 5$	171	43.7 (32.8, 58.1)	0.13	7.5 (5.8, 9.7)	0.78	7.0 (4.2, 11.6)	0.69	137	39.7 (29.6, 53.2)	0.67	6.9 (5.4, 8.8)	0.77	7.6 (4.8, 12.0)	0.19
$greater than or equal to 5$	256	49.0 (36.8, 65.2)	0.01	7.6 (5.9, 9.9)	0.90	9.7 (5.9, 16.2)	0.03	208	40.4 (29.8, 54.7)	0.63	6.5 (5.1, 8.4)	0.87	8.3 (5.2, 13.4)	0.12
Military occupation: fire protection
No	825	30.1 (25.2, 36.0)	—	5.8 (4.9, 6.8)	—	4.3 (3.1, 5.9)	—	357	26.6 (21.8, 32.6)	—	5.3 (4.5, 6.2)	—	4.3 (3.1, 5.8)	—
Yes	5	64.8 (40.7, 103.1)	0.0006	9.9 (6.5, 15.0)	0.009	14.4 (6.3, 32.9)	0.002	5	57.4 (35.6, 92.7)	0.0005	8.5 (5.7, 12.6)	0.009	11.8 (5.6, 24.9)	0.003
Stationed at facility with elevated PFAS in drinking water
No	804	43.5 (33.4, 56.8)	—	7.5 (5.9, 9.6)	—	6.8 (4.2, 10.9)	—	342	39.3 (29.8, 51.7)	—	6.4 (5.1, 8.0)	—	5.4 (3.5, 8.3)	—
Yes	26	44.8 (32.6, 61.5)	0.77	7.6 (5.7, 10.1)	0.90	9.2 (5.2, 16.1)	0.10	20	38.9 (27.3, 55.6)	0.94	7.0 (5.2, 9.4)	0.35	9.3 (5.3, 16.2)	0.003
Stationed at facility with elevated PFAS in groundwater
No	235	46.0 (34.8, 60.7)	—	7.8 (6.1, 10.0)	—	8.5 (5.2, 14.0)	—	50	38.3 (27.9, 52.6)	—	6.8 (5.2, 8.8)	—	7.0 (4.3, 11.5)	—
Yes	595	42.4 (32.1, 56.1)	0.06	7.4 (5.7, 9.5)	0.15	7.3 (4.4, 12.0)	0.04	312	39.9 (29.6, 53.9)	0.61	6.6 (5.2, 8.5)	0.77	7.1 (4.5, 11.4)	0.91

Note: —, no data; CI, confidence interval; GM, geometric mean; PFAS, per- and polyfluoroalkyl substances; PFHxS, perfluorohexanesulfonic acid; PFOA, perfluorooctanoic acid; PFOS, perfluorooctanesulfonic acid.

^{^a}

Least-squares geometric means computed from multiple linear regression models adjusting for all variables listed in the table and case–control status.