. 2022 Jun 22;130(6):067007. doi: 10.1289/EHP10393

Table 2.

Baseline characteristics [ $n$ (%)] of participants in the NHANES follow-up study from 1999–2014 to 31 December 2015 ( $lowercase italic n equals 11,747$ ).

Characteristics	Total ( $lowercase italic n equals 11,747$ )	Total serum PFAS				Serum PFOA concentration				Serum PFOS concentration
Characteristics	Total ( $lowercase italic n equals 11,747$ )	Low ( $lowercase italic n equals 3,913$ )	Medium ( $lowercase italic n equals 5,491$ )	High ( $lowercase italic n equals 2,343$ )	$p$ -Value	Tertile 1 $less than 2.4 nanograms per milliliter$ ( $lowercase italic n equals 3,913$ )	Tertile 2 $2.4 to 4.3 nanograms per milliliter$ ( $lowercase italic n equals 3,842$ )	Tertile 3 $greater than or equal to 4.3 nanograms per milliliter$ ( $lowercase italic n equals 3,992$ )	$p$ -Value	Tertile 1 $less than 7.9 nanograms per milliliter$ ( $lowercase italic n equals 3,886$ )	Tertile 2 $7.9 to 17.1 nanograms per milliliter$ ( $lowercase italic n equals 3,917$ )	Tertile 3 $greater than or equal to 17.1 nanograms per milliliter$ ( $lowercase italic n equals 3,944$ )	$p$ -Value
Deaths	1,251 (7.0)	313 (4.4)	532 (6.4)	406 (13.2)	$less than 0.001$	322 (4.6)	418 (7.2)	511 (9.1)	$less than 0.001$	199 (2.7)	372 (6.0)	680 (12.2)	$less than 0.001$
Heart disease	372 (2.1)	81 (1.0)	184 (2.2)	107 (3.5)	$less than 0.001$	100 (1.4)	128 (2.2)	144 (2.6)	0.158	62 (0.7)	129 (2.2)	181 (3.3)	$less than 0.001$
Cancer	248 (1.4)	43 (0.4)	135 (1.7)	70 (2.2)	0.002	59 (0.7)	74 (1.2)	115 (2.3)	0.008	39 (0.4)	79 (1.3)	130 (2.5)	$less than 0.001$
PFAS excluding PFOA (exposure)
Low	4,160 (36.2)	—	—	—	—	2,802 (74.1)	1,124 (32.7)	234 (5.9)	$less than 0.001$	—	—	—	—
Medium	5,327 (44.0)	—	—	—	—	808 (19.6)	2,113 (52.5)	2,406 (57.9)	$less than 0.001$	—	—	—	—
High	2,260 (19.8)	—	—	—	—	303 (6.3)	605 (14.8)	1,352 (36.2)	$less than 0.001$	—	—	—	—
PFAS excluding PFOS (exposure)
Low	4,133 (35.4)	—	—	—	—	—	—	—	—	3,028 (76.6)	979 (23.3)	126 (2.9)	$less than 0.001$
Medium	5,180 (42.7)	—	—	—	—	—	—	—	—	666 (18.3)	2,076 (52.9)	2,438 (58.5)	$less than 0.001$
High	2,434 (21.9)	—	—	—	—	—	—	—	—	192 (5.1)	862 (23.8)	1,380 (38.5)	$less than 0.001$
Sex
Male	5,681 (48.5)	1,401 (36.4)	2,924 (53.7)	1,356 (56.6)	$less than 0.001$	1,391 (34.8)	1,927 (50.1)	2,363 (59.3)	$less than 0.001$	1,382 (35.2)	1,918 (50.3)	2,381 (61.3)	$less than 0.001$
Female	6,066 (51.5)	2,512 (63.6)	987 (46.3)	2,567 (43.4)	$less than 0.001$	2,522 (65.2)	1,915 (49.9)	1,629 (40.7)	$less than 0.001$	2,504 (64.8)	1,999 (49.7)	1,563 (38.7)	$less than 0.001$
Age (y)^a	42.5	39.6	43.2	45.7	$less than 0.001$	40.3	43.2	43.8	$less than 0.001$	39.3	42.6	46.2	$less than 0.001$
Race/ethnicity
Non-Hispanic White	5,274 (69.4)	1,426 (60.8)	2,877 (77.0)	971 (66.5)	$less than 0.001$	1,357 (58.3)	1,722 (71.1)	2,195 (77.9)	$less than 0.001$	1,527 (63.1)	1,794 (71.8)	1,953 (73.9)	$less than 0.001$
Non-Hispanic Black	2,427 (10.8)	730 (11.1)	1,002 (9.1)	695 (14.2)	0.001	852 (13.3)	782 (10.6)	793 (8.8)	0.005	674 (10.0)	761 (10.1)	992 (12.4)	0.148
Mexican American	2,219 (8.5)	895 (13.1)	1,111 (6.9)	213 (4.4)	$less than 0.001$	875 (12.7)	776 (8.2)	568 (4.9)	$less than 0.001$	821 (12.2)	788 (8.3)	610 (4.6)	$less than 0.001$
Other	1,827 (11.3)	862 (14.9)	501 (7.0)	464 (14.9)	$less than 0.001$	829 (15.7)	562 (10.1)	436 (8.4)	$less than 0.001$	864 (14.7)	574 (9.8)	389 (9.1)	$less than 0.001$
Education
With high school education	5,266 (56.1)	1,790 (56.3)	2,346 (54.8)	1,130 (58.6)	0.225	1,703 (54.5)	1,765 (57.6)	1,798 (56.3)	0.374	1,814 (57.0)	1,804 (57.5)	1,648 (53.4)	0.131
Without high school education	5,606 (40.2)	1,828 (39.3)	2,648 (41.2)	1,130 (39.5)	0.635	1,927 (41.1)	1,780 (38.8)	1,899 (40.6)	0.544	1,772 (38.5)	1,813 (38.8)	2,021 (43.7)	0.029
Missing	875 (3.7)	295 (4.4)	497 (4.0)	83 (1.8)	0.004	283 (4.4)	297 (3.6)	295 (3.1)	0.299	300 (7.5)	300 (7.2)	275 (7.6)	0.939
Income
$Greater than or equal to 20,000 dollars$	8,443 (80.7)	2,826 (79.7)	3,863 (80.2)	1,754 (83.5)	0.062	2,785 (78.9)	2,718 (80.3)	2,940 (82.7)	0.094	2,811 (79.0)	2,828 (82.0)	2,804 (81.1)	0.218
$Less than 20,000 dollars$	2,654 (15.3)	874 (16.0)	1,318 (16.0)	462 (12.7)	0.057	926 (17.4)	890 (15.1)	838 (13.8)	0.078	868 (16.7)	892 (14.7)	894 (14.6)	0.339
Missing	650 (3.9)	213 (4.3)	310 (3.8)	127 (3.8)	0.803	202 (3.8)	234 (4.6)	214 (3.5)	0.428	207 (4.3)	197 (3.3)	246 (4.3)	0.417
Smoking status
Never	5,989 (52.4)	2,211 (57.2)	2,557 (48.3)	1,221 (53.7)	$less than 0.001$	2,242 (57.8)	1,881 (51.0)	1,866 (48.9)	$less than 0.001$	2,152 (55.9)	1,985 (52.3)	1,852 (48.7)	0.005
Former smoker	2,739 (23.5)	753 (20.0)	1,354 (25.0)	632 (26.0)	0.003	776 (19.7)	938 (25.0)	1,025 (25.6)	0.003	713 (19.2)	935 (24.3)	1,091 (27.5)	$less than 0.001$
Current smoker	2,264 (21.0)	749 (20.1)	1,101 (22.9)	414 (18.6)	0.054	699 (19.6)	753 (20.9)	812 (22.4)	0.306	819 (22.2)	715 (19.9)	730 (21.0)	0.451
Missing	755 (3.0)	200 (2.7)	479 (3.8)	76 (1.7)	0.016	196 (2.8)	270 (3.1)	289 (3.0)	0.922	202 (2.7)	282 (3.4)	271 (2.7)	0.563
Alcohol intake (d/wk)
$less than 1$	5,594 (47.4)	1,904 (49.7)	2,675 (48.3)	1,015 (41.4)	$less than 0.001$	1,900 (49.1)	1,856 (47.8)	1,838 (45.4)	0.243	1,844 (49.2)	1,868 (47.9)	1,882 (44.6)	0.409
$greater than or equal to 1$	3,011 (32.2)	863 (27.9)	1,410 (32.6)	738 (38.1)	$less than 0.001$	811 (26.1)	992 (33.1)	1,208 (36.6)	$less than 0.001$	968 (31.4)	995 (32.6)	1,048 (32.8)	0.769
Missing	3,142 (20.5)	1,146 (22.4)	1,406 (19.0)	590 (20.5)	0.170	1,202 (24.8)	994 (19.0)	946 (18.0)	$less than 0.001$	1,074 (19.4)	1,054 (19.5)	1,014 (22.6)	0.237
Physical activity (times/month)
$less than 15$	1,789 (15.7)	218 (4.9)	1,234 (22.5)	337 (17.9)	$less than 0.001$	297 (6.9)	555 (13.9)	937 (25.0)	$less than 0.001$	167 (3.5)	539 (14.4)	1,083 (30.7)	$less than 0.001$
$greater than or equal to 15$	1,115 (9.4)	148 (3.4)	750 (12.9)	217 (11.7)	$less than 0.001$	218 (5.3)	356 (8.9)	541 (13.6)	$less than 0.001$	114 (2.8)	350 (8.9)	651 (17.5)	$less than 0.001$
Missing	8,843 (74.9)	3,547 (91.7)	3,507 (64.6)	1,789 (70.4)	$less than 0.001$	3,398 (87.8)	2,931 (77.1)	2,514 (61.4)	$less than 0.001$	3,605 (93.7)	3,028 (76.7)	2,210 (51.8)	$less than 0.001$
Hypertension
With	2,088 (14.8)	528 (12.2)	1,075 (16.1)	485 (16.1)	0.018	568 (12.2)	714 (15.4)	806 (16.5)	0.019	3,223 (11.6)	3,085 (14.4)	2,862 (18.8)	$less than 0.001$
Without	9,170 (81.2)	3,219 (83.8)	4,207 (80.1)	1,744 (79.2)	0.021	3,150 (83.2)	2,988 (81.0)	3,032 (79.5)	0.103	503 (84.4)	679 (82.0)	906 (76.6)	$less than 0.001$
Missing	489 (4.1)	166 (4.0)	209 (3.8)	114 (4.7)	0.572	195 (4.6)	140 (3.6)	154 (3.9)	0.506	160 (4.0)	154 (3.7)	175 (4.6)	0.586
Diabetes
With	1,282 (8.8)	438 (9.6)	575 (8.3)	269 (8.4)	0.520	501 (10.6)	429 (9.1)	352 (6.7)	0.008	400 (9.1)	434 (8.3)	448 (8.9)	0.805
Without	10,236 (89.5)	3,397 (88.3)	4,822 (90.3)	2,017 (89.7)	0.328	3,339 (87.6)	3,336 (88.9)	3,561 (91.8)	0.070	3,415 (89.1)	3,406 (90.1)	3,415 (89.3)	0.742
Missing	229 (1.7)	78 (2.1)	93 (1.4)	57 (1.9)	0.479	73 (1.8)	77 (1.9)	79 (1.5)	0.775	71 (1.8)	77 (1.6)	81 (1.8)	0.925
Healthy eating index (tertile)
First	2,332 (18.9)	594 (14.2)	1,179 (20.5)	559 (22.9)	$less than 0.001$	694 (17.0)	723 (17.7)	915 (22.0)	0.008	636 (15.6)	764 (19.4)	932 (22.7)	$less than 0.001$
Second	2,350 (18.9)	846 (20.5)	1,081 (18.6)	423 (17.2)	0.531	834 (20.4)	779 (19.5)	737 (17.7)	0.296	898 (22.2)	776 (18.7)	676 (16.1)	0.002
Third	2,344 (18.9)	930 (22.6)	1,094 (19.0)	320 (12.7)	$less than 0.001$	835 (20.1)	869 (21.5)	640 (15.0)	$less than 0.001$	842 (20.7)	795 (17.8)	707 (17.1)	0.089
Missing	4,721 (43.2)	1,543 (42.7)	2,137 (41.9)	1,041 (47.2)	0.036	1,550 (42.5)	1,471 (41.3)	1,700 (45.3)	0.179	1,510 (41.5)	1,582 (44.1)	1,629 (44.1)	0.399
BMI ( ${kg / m}^{2}$ )
Normal ( $less than 25.0$ )	3,672 (31.9)	1,166 (30.1)	1,746 (32.3)	760 (33.9)	0.188	1,224 (31.4)	1,221 (32.7)	1,227 (31.6)	0.798	1,228 (32.5)	1,236 (32.7)	1,208 (30.2)	0.411
Overweight (25.0–29.9)	3,867 (33.4)	1,191 (30.0)	1,855 (34.7)	821 (36.1)	0.011	1,190 (30.9)	1,274 (33.3)	1,403 (35.5)	0.090	1,175 (30.8)	1,310 (34.4)	1,382 (35.2)	0.080
Obese ( $greater than or equal to 30.0$ )	4,039 (33.5)	1,482 (38.3)	1,819 (32.0)	738 (29.3)	$less than 0.001$	1,411 (35.6)	1,303 (33.0)	1,325 (32.2)	0.243	1,416 (35.1)	1,319 (31.9)	1,304 (33.6)	0.317
Missing	169 (1.2)	74 (1.7)	71 (1.0)	24 (0.7)	0.095	88 (2.0)	44 (0.9)	37 (0.7)	0.016	67 (1.6)	52 (1.0)	50 (0.9)	0.288
Ccr (mL/min)
$greater than or equal to 70$	9,826 (87.2)	3,431 (89.9)	4,505 (86.0)	1,890 (85.5)	0.006	3,319 (87.9)	3,222 (87.3)	3,285 (86.5)	0.642	3,425 (90.0)	3,282 (87.7)	3,119 (83.5)	$less than 0.001$
50–70	1,101 (7.6)	238 (5.1)	582 (8.6)	281 (9.6)	$less than 0.001$	295 (5.9)	372 (8.3)	434 (8.6)	0.044	237 (5.4)	377 (7.6)	487 (10.2)	$less than 0.001$
30–49.9	543 (3.3)	122 (2.5)	290 (3.8)	131 (3.7)	0.197	151 (3.1)	183 (3.2)	209 (3.7)	0.726	111 (2.3)	177 (3.2)	255 (4.7)	0.011
$less than 30$	126 (0.7)	60 (1.0)	47 (0.6)	19 (0.4)	0.244	69 (1.2)	28 (0.5)	29 (0.4)	0.065	55 (0.9)	33 (0.6)	38 (0.6)	0.649
Missing	151 (1.2)	62 (1.5)	67 (1.1)	22 (0.7)	0.230	79 (1.9)	37 (0.8)	35 (0.8)	0.030	58 (1.4)	48 (1.0)	45 (1.1)	0.687
Total cholesterol (mg/dL)
Concentration^a^,b	11,744 (191.2)	3,912 (186.9)	5,489 (192.3)	2,343 (195.9)	$less than 0.001$	3,912 (185.9)	3,842 (191.4)	3,990 (195.7)	$less than 0.001$	3,886 (187.3)	3,916 (189.7)	3,942 (197.3)	$less than 0.001$
Missing	3 (—)	1 (—)	2 (—)	0 (—)	—	1 (—)	0 (—)	2 (—)	—	0 (—)	1 (—)	2 (—)	—
Serum cotinine (ng/dL)
Concentration^a^,b	11,705 (0.37)	3,907 (0.26)	5,457 (0.50)	2,341 (0.32)	$less than 0.001$	3,901 (0.26)	3,835 (0.35)	3,969 (0.53)	$less than 0.001$	3,882 (0.32)	3,912 (0.34)	3,911 (0.48)	$less than 0.001$
Missing	42 (—)	6 (—)	34 (—)	2 (—)	—	12 (—)	7 (—)	23 (—)	—	4 (—)	5 (—)	33 (—)	—

Note: Percentages, means, and cut points were weight-adjusted using NHANES-specified sampling weights. For categorical variables, $p$ -values were calculated using chi-square test, and for continuous variables, $p$ -values were calculated using one-way ANOVA (normal distribution) or Kruskal–Wallis H test (non-normal distribution). Samples with test values below the LOQ were substituted with the value of the LOQ divided by the square root of 2. —, not applicable; ANOVA, analysis of variance; BMI, body mass index; Ccr, creatinine clearance rate; GM, geometric mean; LOQ, limit of quantification; NHANES, National Health and Nutrition Examination Survey; PFAS, per- and polyfluoroalkyl substances; PFOA, perfluorooctanoic acid; PFOS, perfluorooctane sulfonic acid.

^aAge, total cholesterol, and cotinine were treated as continuous variables.

^bNon-normal distribution data presented as GMs.