. 2021 Sep 13;129(9):097009. doi: 10.1289/EHP7668

Table 1.

Distribution of recent and remote 3-y average $P M_{2 .5}$ and ${NO}_{2}$ exposures and population characteristics [ $mean \pm SD$ or $n$ (%)], overall and according to age at WHIMS-ECHO enrollment and cognitive function trajectory subgroups determined by a latent class mixed model with follow-up time and age at WHIMS-ECHO enrollment as the only predictors.

Characteristics	All women ( $n = 2,056$ )	Age $\leq 80 y$ ( $n = 828$ )	Age $> 80 y$ ( $n = 1,128$ )	$p$ -Value^a	Age $\leq 80 y$			Age $> 80 y$
Characteristics	All women ( $n = 2,056$ )	Age $\leq 80 y$ ( $n = 828$ )	Age $> 80 y$ ( $n = 1,128$ )	$p$ -Value^a	Slow-decliners ( $n = 643$ )	Fast-decliners ( $n = 185$ )	$p$ -Value^b	Cognitively resilient ( $n = 351$ )	Steady-decliners ( $n = 877$ )	$p$ -Value^c
Air Pollution Exposures
Remote $P M_{2 .5}$ ( ${μ g / m}^{3}$ )	$13.29 \pm 2.71$	$13.17 \pm 2.54$	$13.36 \pm 2.81$	0.11	$13.20 \pm 2.58$	$13.05 \pm 2.42$	0.48	$13.44 \pm 2.87$	$13.33 \pm 2.79$	0.54
Recent $P M_{2 .5}$ ( ${μ g / m}^{3}$ )	$10.52 \pm 2.01$	$10.53 \pm 2.02$	$10.51 \pm 2.00$	0.85	$10.52 \pm 2.06$	$10.56 \pm 1.91$	0.81	$10.50 \pm 1.96$	$10.51 \pm 2.01$	0.93
Remote ${NO}_{2}$ (ppb)	$15.82 \pm 7.26$	$14.92 \pm 6.96$	$16.43 \pm 7.39$	$< 0.001$	$14.95 \pm 6.85$	$14.80 \pm 7.33$	0.79	$16.42 \pm 7.69$	$16.43 \pm 7.28$	0.97
Recent ${NO}_{2}$ (ppb)	$10.47 \pm 4.98$	$9.87 \pm 4.84$	$10.87 \pm 5.04$	$< 0.001$	$9.80 \pm 4.71$	$10.14 \pm 5.26$	0.40	$10.77 \pm 5.22$	$10.91 \pm 4.97$	0.66
Age at WHIMS-ECHO enrollment (y)	$81.51 \pm 3.52$	$78.19 \pm 1.20$	$83.75 \pm 2.71$	$< 0.001$	$78.14 \pm 1.20$	$78.37 \pm 1.18$	0.02	$83.36 \pm 2.65$	$83.91 \pm 2.73$	0.001
Neighborhood SES^d
At WHI inception	$0.59 \pm 5.26$	$0.08 \pm 5.16$	$0.93 \pm 5.31$	$< 0.001$	$0.05 \pm 5.22$	$0.17 \pm 4.96$	0.78	$0.91 \pm 5.13$	$0.94 \pm 5.38$	0.93
At WHIMS-ECHO enrollment	$0.12 \pm 5.11$	$- 0.34 \pm 5.03$	$0.44 \pm 5.14$	$< 0.001$	$- 0.36 \pm 5.02$	$- 0.29 \pm 5.09$	0.88	$0.52 \pm 5.01$	$0.40 \pm 5.19$	0.73
Region				$< 0.001$			0.18			0.98
Northeast	662 (32.2)	273 (33.0)	389 (31.7)		200 (31.1)	73 (39.5)		112 (31.9)	277 (31.6)
South	408 (19.8)	183 (22.1)	225 (18.3)		145 (22.6)	38 (20.5)		62 (17.7)	163 (18.6)
Midwest	498 (24.2)	225 (27.2)	273 (22.2)		178 (27.7)	47 (25.4)		80 (22.8)	193 (22.0)
West	488 (23.7)	147 (17.8)	341 (27.8)		120 (18.7)	27 (14.6)		97 (27.6)	244 (27.8)
Race/ethnicity				0.10			0.73			0.35
American Indian or Alaskan Native	4 (0.2)	1 (0.1)	3 (0.2)		1 (0.2)	0		2 (0.6)	1 (0.1)
Asian or Pacific Islander	17 (0.8)	6 (0.7)	11 (0.9)		4 (0.6)	2 (1.1)		1 (0.3)	10 (1.1)
Black, non-Hispanic	107 (5.2)	57 (6.9)	50 (4.1)		44 (6.8)	13 (7.0)		10 (2.8)	40 (4.6)
Hispanic/Latino	29 (1.4)	13 (1.6)	16 (1.3)		12 (1.9)	1 (0.5)		4 (1.1)	12 (1.4)
White, non-Hispanic	1,875 (91.2)	744 (89.9)	1,131 (92.1)		577 (89.7)	167 (90.3)		329 (93.7)	802 (91.4)
Other^e	23 (1.1)	7 (0.9)	16 (1.3)		5 (0.8)	2 (1.1)		5 (1.4)	11 (1.3)
Missing	1 (0.1)	0	1 (0.1)		0	0		0	1 (0.1)
Education				0.58			0.52			0.16
$\leq High$ school or GED	500 (24.3)	196 (23.7)	304 (24.8)		158 (24.6)	38 (20.5)		74 (21.1)	230 (26.2)
$> High$ school to $< 4 y$ of college	789 (38.4)	329 (39.7)	460 (37.5)		253 (39.4)	76 (41.1)		136 (38.8)	324 (36.9)
$\geq 4 y$ of college	767 (37.3)	303 (36.6)	464 (37.8)		232 (36.1)	71 (38.4)		141 (40.2)	323 (36.8)
Employment				$< 0.001$			0.82			0.13
Currently working	321 (15.6)	181 (21.9)	140 (11.4)		143 (22.2)	38 (20.5)		48 (13.7)	92 (10.5)
Not working	195 (9.5)	81 (9.8)	114 (9.3)		64 (10.0)	17 (9.2)		26 (7.4)	88 (10.0)
Retired	1,540 (74.9)	566 (68.4)	974 (79.3)		436 (67.8)	130 (70.3)		277 (78.9)	697 (79.5)
Income ( $$$ )				0.11			0.59			0.002
$< 9,999$	68 (3.3)	31 (3.7)	37 (3)		23 (3.6)	8 (4.3)		6 (1.7)	31 (3.5)
10,000–34,999	906 (44.1)	350 (42.3)	556 (45.3)		270 (42.0)	80 (43.2)		158 (45.0)	398 (45.4)
35,000–49,999	450 (21.9)	206 (24.9)	244 (19.9)		165 (25.7)	41 (22.2)		58 (16.5)	186 (21.2)
50,000–74,999	321 (15.6)	125 (15.1)	196 (16)		97 (15.1)	28 (15.1)		75 (21.4)	121 (13.8)
$\geq 75,000$	212 (10.3)	80 (9.7)	132 (10.7)		64 (10.0)	16 (8.6)		43 (12.3)	89 (10.1)
Not known	99 (4.8)	36 (4.3)	63 (5.1)		24 (3.7)	12 (6.5)		11 (3.1)	52 (5.9)
Smoking status				$< 0.001$			0.62			0.94
Never smoked	1,138 (55.4)	416 (50.2)	722 (58.8)		328 (51.0)	88 (47.6)		205 (58.4)	517 (59.0)
Past smoker	823 (40.0)	359 (43.4)	464 (37.8)		273 (42.5)	86 (46.5)		133 (37.9)	331 (37.7)
Current smoker	95 (4.6)	53 (6.4)	42 (3.4)		42 (6.5)	11 (5.9)		13 (3.7)	29 (3.3)
Alcohol use				0.66			0.73			0.57
Nondrinker	243 (11.8)	101 (12.2)	142 (11.6)		76 (11.8)	25 (13.5)		35 (10.0)	107 (12.2)
Past drinker	342 (16.6)	129 (15.6)	213 (17.3)		97 (15.1)	32 (17.3)		57 (16.2)	156 (17.8)
$< 1$ drink/d	1,204 (58.6)	494 (59.7)	710 (57.8)		390 (60.7)	104 (56.2)		209 (59.5)	501 (57.1)
$\geq 1$ drink/d	267 (13)	104 (12.6)	163 (13.3)		80 (12.4)	24 (13.0)		50 (14.2)	113 (12.9)
Physical activity^f				0.71			0.56			0.49
No activity	1,109 (53.9)	445 (53.7)	664 (54.1)		344 (53.5)	101 (54.6)		184 (52.4)	480 (54.7)
Some activity	114 (5.5)	47 (5.7)	67 (5.5)		39 (6.1)	8 (4.3)		20 (5.7)	47 (5.4)
2–4 episodes/wk	439 (21.4)	169 (20.4)	270 (22.0)		135 (21.0)	34 (18.4)		73 (20.8)	197 (22.5)
$> 4$ episodes/wk	394 (19.2)	167 (20.2)	227 (18.5)		125 (19.4)	42 (22.7)		74 (21.1)	153 (17.4)
Hypercholesterolemia				0.99			0.15			0.86
No	1,716 (83.5)	691 (83.5)	1,025 (83.5)		543 (84.4)	148 (80.0)		294 (83.8)	731 (83.4)
Yes	340 (16.5)	137 (16.5)	203 (16.5)		100 (15.6)	37 (20.0)		57 (16.2)	146 (16.6)
Diabetes				0.86			0.05			0.64
No	1,976 (96.1)	795 (96.0)	1,181 (96.2)		622 (96.7)	173 (93.5)		339 (96.6)	842 (96.0)
Yes	80 (3.9)	33 (4.0)	47 (3.8)		21 (3.3)	12 (6.5)		12 (3.4)	35 (4.0)
Hormone treatment				0.58			0.33			0.33
No	1,127 (54.8)	460 (55.6)	667 (54.3)		363 (56.5)	97 (52.4)		183 (52.1)	484 (55.2)
Yes	929 (45.2)	368 (44.4)	561 (45.7)		280 (43.5)	88 (47.6)		168 (47.9)	393 (44.8)
Hypertension
At WHI inception				0.37			0.01			0.14
No	1,357 (66.0)	556 (67.1)	801 (65.2)		446 (69.4)	110 (59.5)		240 (68.4)	561 (64.0)
Yes	699 (34.0)	272 (32.9)	427 (34.8)		197 (30.6)	75 (40.5)		111 (31.6)	316 (36.0)
At WHIMS-ECHO enrollment				0.04			0.24			0.18
No	676 (32.9)	294 (35.5)	382 (31.1)		235 (36.5)	59 (31.9)		119 (33.9)	263 (30.0)
Yes	1,380 (67.1)	534 (64.5)	846 (68.9)		408 (63.5)	126 (68.1)		232 (66.1)	614 (70.0)
Cardiovascular disease history				0.22			0.18			0.34
At WHI inception
No	1,759 (85.6)	718 (86.7)	1,041 (84.8)		563 (87.6)	155 (83.8)		303 (86.3)	738 (84.2)
Yes	297 (14.4)	110 (13.3)	187 (15.2)		80 (12.4)	30 (16.2)		48 (13.7)	139 (15.8)
At WHIMS-ECHO enrollment				0.01			0.28			0.77
No	1,583 (77.0)	663 (80.1)	920 (74.9)		520 (80.9)	143 (77.3)		265 (75.5)	655 (74.7)
Yes	473 (23.0)	165 (19.9)	308 (25.1)		123 (19.1)	42 (22.7)		86 (24.5)	222 (25.3)
WHI hormone therapy assignment				0.44			0.38			0.74
Estrogen-alone control	375 (18.2)	149 (18.0)	226 (18.4)		110 (17.1)	39 (21.1)		71 (20.2)	155 (17.7)
Estrogen-alone intervention	362 (17.6)	159 (19.2)	203 (16.5)		120 (18.7)	39 (21.1)		55 (15.7)	148 (16.9)
$Estrogen + progestin$ control	688 (33.5)	267 (32.2)	421 (34.3)		209 (32.5)	58 (31.4)		117 (33.3)	304 (34.7)
$Estrogen + progestin$ intervention	631 (30.7)	253 (30.6)	378 (30.8)		204 (31.7)	49 (26.5)		108 (30.8)	270 (30.8)

Note: All characteristics were classified at WHI inception (1993–1998) unless otherwise indicated. All $p$ -values were calculated using $t$ -test for continuous variables, Fisher’s exact test for race/ethnicity, or chi-square test for other categorical variables. GED, General Education Development; ${NO}_{2}$ , nitrogen dioxide; ${PM}_{2.5}$ , fine particulate matter (PM with an aerodynamic diameter of $\leq 2.5 μ m$ ); SD, standard deviation; SES, socioeconomic status; WHI, Women’s Health Initiative; WHIMS-ECHO, Women’s Health Initiative Memory Study–Epidemiology of Cognitive Health Outcomes.

^{^a}

$p$ -Value comparing women $\leq 80$ vs. $> 80$ years of age.

^{^b}

$p$ -Value comparing women $\leq 80$ years of age classified as slow- vs. fast-decliners.

^{^c}

$p$ -Value comparing women $> 80$ years of age classified as Cognitively resilient vs. steady-decliners.

^{^d}

Neighborhood SES is the sum of six standardized U.S. Census tract–level variables measuring domains of wealth/income, education, and occupation. Higher values indicate higher neighborhood SES.

^{^e}

“Other” race/ethnicity includes women who did not select one of the five specific race/ethnicity groups.

^{^f}

Moderate or strenuous physical activity for $\geq 20$ min.