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. 2022 Feb 3;19(2):e1003893. doi: 10.1371/journal.pmed.1003893

Table 2. Distribution of AQ measures by population characteristics in the WHIMS-ECHO cohort, 1998 to 2018.

Analytic sample for TICSm analyses Analytic sample for CVLT analyses
AQ improvement in PM2.5 (μg/m3)a AQ improvement in NO2 (ppb)a AQ improvement in PM2.5 (μg/m3)a AQ improvement in NO2 (ppb)a
Population characteristics N Mean ± SD p b Mean ± SD p b N Mean ± SD p b Mean ± SD p b
Overall 2,232 2.73 ± 1.63 5.27 ± 3.46 1,721 2.78 ± 1.68 5.34 ± 3.49
Region <0.001 <0.001 <0.001 <0.001
 Northeast 718 3.01 ± 0.95 5.72 ± 3.26 551 3.02 ± 0.92 5.73 ± 3.23
 South 443 2.50 ± 1.28 4.92 ± 3.08 329 2.54 ± 1.26 5.02 ± 3.08
 Midwest 549 2.15 ± 1.22 4.36 ± 2.32 428 2.12 ± 1.21 4.36 ± 2.25
 West 522 3.18 ± 2.55 5.89 ± 4.60 413 3.35 ± 2.63 6.08 ± 4.73
Age 0.009 0.004 0.002 0.002
 ≤80 years 879 2.62 ± 1.50 5.00 ± 3.23 731 2.64 ± 1.54 5.03 ± 3.32
 >80 years 1,353 2.81 ± 1.71 5.44 ± 3.58 990 2.89 ± 1.76 5.56 ± 3.60
Ethnicity <0.001 <0.001 <0.001 <0.001
 Black (not Hispanic) 116 3.28 ± 1.39 6.84 ± 2.67 86 3.49 ± 1.31 6.91 ± 2.64
 White (not Hispanic) 2,042 2.68 ± 1.63 5.13 ± 3.47 1,576 2.72 ± 1.67 5.21 ± 3.51
 Other 74 3.42 ± 1.84 6.42 ± 3.30 59 3.51 ± 1.94 6.46 ± 3.39
Education 0.04 0.09 0.06 0.48
 ≤High school or GED 564 2.64 ± 1.49 5.08 ± 3.22 406 2.65 ± 1.51 5.17 ± 3.32
 >High school but <4 years of college 864 2.69 ± 1.77 5.19 ± 3.62 651 2.75 ± 1.82 5.34 ± 3.74
 ≥4 years of college 804 2.85 ± 1.57 5.47 ± 3.43 664 2.89 ± 1.63 5.44 ± 3.35
Employment 0.81 0.33 0.84 0.49
 Currently working 348 2.78 ± 1.63 5.51 ± 3.52 279 2.81 ± 1.68 5.57 ± 3.62
 Not working 210 2.76 ± 1.69 5.13 ± 3.64 166 2.84 ± 1.76 5.32 ± 3.77
 Retired 1,674 2.72 ± 1.63 5.23 ± 3.42 1,276 2.77 ± 1.67 5.29 ± 3.43
Income (US$) 0.01 0.04 0.04 0.03
 <9,999 74 2.73 ± 1.98 5.02 ± 3.93 52 2.72 ± 2.10 5.00 ± 3.97
 10,000 to 34,999 1,000 2.64 ± 1.66 5.18 ± 3.54 742 2.73 ± 1.70 5.30 ± 3.50
 35,000 to 74,999 824 2.78 ± 1.55 5.22 ± 3.24 663 2.79 ± 1.61 5.21 ± 3.37
 75,000 or more 220 3.07 ± 1.73 5.95 ± 3.88 186 3.10 ± 1.76 6.10 ± 3.91
 Do not know 114 2.55 ± 1.43 5.11 ± 2.88 78 2.48 ± 1.36 5.17 ± 2.80
Smoking status 0.98 0.66 0.80 0.67
 Never smoked 1,239 2.74 ± 1.67 5.27 ± 3.38 954 2.80 ± 1.71 5.38 ± 3.44
 Past smoker 890 2.73 ± 1.59 5.23 ± 3.56 689 2.75 ± 1.65 5.25 ± 3.57
 Current smoker 103 2.76 ± 1.54 5.55 ± 3.52 78 2.83 ± 1.56 5.52 ± 3.42
Alcohol use 0.48 <0.001 0.54 0.006
 Nondrinker 261 2.59 ± 1.72 4.60 ± 3.18 191 2.62 ± 1.78 4.63 ± 3.30
 Past drinker 372 2.75 ± 1.67 5.37 ± 3.78 266 2.85 ± 1.71 5.52 ± 3.92
 <1 drink per day 1,315 2.76 ± 1.60 5.46 ± 3.41 1,036 2.79 ± 1.65 5.49 ± 3.43
 ≥1 drink per day 284 2.71 ± 1.67 4.85 ± 3.36 228 2.79 ± 1.67 5.02 ± 3.35
Moderate or strenuous physical activities ≥20 minutes 0.82 0.25 0.74 0.21
 No activity 1,207 2.71 ± 1.63 5.28 ± 3.41 917 2.78 ± 1.68 5.42 ± 3.51
 Some activity 124 2.76 ± 1.24 5.56 ± 3.18 91 2.75 ± 1.23 5.58 ± 3.16
 2 to 4 episodes/week 481 2.79 ± 1.68 5.38 ± 3.54 376 2.85 ± 1.74 5.40 ± 3.51
 >4 episodes/week 420 2.72 ± 1.69 4.99 ± 3.56 337 2.72 ± 1.70 4.98 ± 3.51
BMI (kg/m 2 ) 0.43 0.48 0.91 0.09
 <25 619 2.80 ± 1.64 5.19 ± 3.37 476 2.81 ± 1.70 5.10 ± 3.34
 25 to 29 815 2.74 ± 1.64 5.21 ± 3.25 633 2.76 ± 1.68 5.30 ± 3.29
 ≥30 798 2.68 ± 1.62 5.38 ± 3.72 612 2.78 ± 1.66 5.56 ± 3.79
Hypertension 0.82 0.52 0.63 0.31
 No 1,461 2.73 ± 1.65 5.23 ± 3.52 1,152 2.77 ± 1.71 5.28 ± 3.54
 Yes 771 2.75 ± 1.60 5.33 ± 3.33 569 2.81 ± 1.61 5.46 ± 3.38
Hypercholesterolemia 0.12 0.97 0.44 0.97
 No 1,855 2.71 ± 1.65 5.26 ± 3.53 1,438 2.77 ± 1.70 5.34 ± 3.57
 Yes 377 2.85 ± 1.56 5.27 ± 3.04 283 2.85 ± 1.56 5.34 ± 3.09
Diabetes 0.27 0.42 0.07 0.11
 No 2,143 2.73 ± 1.64 5.25 ± 3.47 1,655 2.77 ± 1.68 5.31 ± 3.50
 Yes 89 2.92 ± 1.50 5.56 ± 3.16 66 3.15 ± 1.48 6.02 ± 3.28
CVD history 0.95 0.94 0.95 0.83
 No 1,907 2.74 ± 1.65 5.27 ± 3.52 1,476 2.78 ± 1.70 5.34 ± 3.58
 Yes 325 2.73 ± 1.53 5.25 ± 3.04 245 2.78 ± 1.52 5.29 ± 2.94
Any prior postmenopausal hormone treatment 0.84 0.22 0.90 0.29
 No 1,218 2.73 ± 1.44 5.35 ± 3.31 935 2.79 ± 1.47 5.42 ± 3.29
 Yes 1,014 2.74 ± 1.84 5.17 ± 3.62 786 2.78 ± 1.90 5.24 ± 3.72
WHI hormone therapy assignment 0.13 0.02 0.03 0.09
 CEE alone placebo 400 2.81 ± 1.74 5.24 ± 3.33 306 2.89 ± 1.84 5.35 ± 3.43
 CEE alone 403 2.57 ± 1.65 4.80 ± 3.30 302 2.53 ± 1.69 4.88 ± 3.37
 CEE+MPA placebo 733 2.77 ± 1.55 5.45 ± 3.53 578 2.84 ± 1.58 5.47 ± 3.46
 CEE+MPA 696 2.75 ± 1.64 5.35 ± 3.52 535 2.79 ± 1.66 5.44 ± 3.61
ApoE 0.01 0.92 0.047 0.87
 e2/2+e2/3+e3/3 1,239 2.81 ± 1.55 5.33 ± 3.46 984 2.82 ± 1.58 5.39 ± 3.45
 e2/4+e3/4+e4/4 372 2.56 ± 1.77 5.31 ± 3.63 269 2.59 ± 1.88 5.35 ± 3.73

aRecent exposures were the 3-year average exposures estimated at the WHIMS-ECHO enrollment. Remote exposures were the 3-year average exposures estimated 10 years before the WHIMS-ECHO enrollment. AQ improvement was defined as reduction from the remote to recent exposures over the 10-year period.

bp-Values were calculated using ANOVA F-tests for mean exposures.

ApoE, Apolipoprotein E; AQ, air quality; BMI, body mass index; CEE, conjugated equine estrogens; CVD, cardiovascular disease; CVLT, California Verbal Learning Test; GED, general educational development; MPA, medroxyprogesterone acetate; NO2, nitrogen dioxide; PM2.5, fine particulate matter; ppb, parts per billion; SD, standard deviation; TICSm, modified Telephone Interview for Cognitive Status; WHI, Women’s Health Initiative; WHIMS-ECHO, Women’s Health Initiative Memory Study-Epidemiology of Cognitive Health Outcomes.