TABLE 2.
Distribution of potential confounders by pollutant terciles
| Distribution of potential confounders by pollutant terciles and ANOVA | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| AGE | TIV | Education | Physical activity | Sex | APOE | Smoker | ||||
| (years) | (cc) | (years) | (mets/day) | BMI | male/total | ε4 carrier | Ever | Current | ||
| NO2 | Tercile 1: | 58.2 (8.0) | 1454.2 (167.7) | 14.0 (3.6) | 2512 (1889) | 26.0 (3.7) | 26 M / 71 | 32 / 71 | 58 / 71 | 21 / 71 |
| Tercile 2: | 59.0 (7.4) | 1493.3 (153.2) | 13.8 (3.2) | 2720 (2351) | 27.1 (3.5) | 30 M / 70 | 40 / 70 | 56 / 70 | 15 / 70 | |
| Tercile 3: | 58.7 (7.2) | 1523.7 (164.2) | 14.5 (3.1) | 2483 (2250) | 27.0 (4.3) | 30 M / 71 | 35 / 71 | 63 / 71 | 23 / 71 | |
| ANOVA | 0.808 | 0.039 * | 0.517 | 0.779 | 0.16 | |||||
| PM2.5 | Tercile 1: | 58.4 (8.1) | 1453.4 (155.7) | 13.9 (3.4) | 2442 (1991) | 26.5 (3.7) | 27 M / 71 | 34 / 71 | 55 / 71 | 18 / 71 |
| Tercile 2: | 59.4 (7.5) | 1505.1 (162.0) | 14.1 (3.4) | 2875 (2184) | 26.4 (3.9) | 32 M / 70 | 38 / 71 | 60 / 70 | 15 / 70 | |
| Tercile 3: | 58.1 (6.9) | 1513.0 (168.7) | 14.3 (3.2) | 2401 (2304) | 27.3 (3.9) | 27 M / 71 | 35 / 70 | 62 / 71 | 26 / 71 | |
| ANOVA | 0.554 | 0.062 | 0.723 | 0.357 | 0.322 | |||||
| Lden | Tercile 1: | 57.9 (7.3) | 1497.0 (164.1) | 14.1 (3.3) | 2735 (2389) | 27.0 (3.8) | 34 M / 71 | 39 / 71 | 57 / 71 | 17 / 71 |
| Tercile 2: | 58.1 (8.0) | 1448.8 (144.1) | 14.2 (3.5) | 2417 (1843) | 25.9 (3.5) | 21 M / 70 | 33 / 70 | 59 / 70 | 21 / 70 | |
| Tercile 3: | 59.9 (7.3) | 1526.0 (174.3) | 14.0 (3.3) | 2561 (2242) | 27.4 (4.1) | 31 M / 71 | 35 / 71 | 61 / 71 | 21 / 71 | |
| ANOVA | 0.238 | 0.017 * | 0.981 | 0.682 | 0.045 * | |||||
| NDVI 300 m | Tercile 1: | 58.9 (7.5) | 1498.2 (168.6) | 14.1 (3.1) | 2504 (2237) | 27.2 (4.2) | 30 M / 71 | 34 / 71 | 60 / 71 | 23 / 71 |
| Tercile 2: | 59.2 (7.2) | 1495.0 (159.1) | 14.1 (3.3) | 2650 (2057) | 26.5 (3.6) | 26 M / 71 | 38 / 71 | 58 / 71 | 16 / 71 | |
| Tercile 3: | 57.7 (7.9) | 1478.2 (164.6) | 14.2 (3.7) | 2561 (2219) | 26.6 (3.8) | 30 M / 70 | 35 / 70 | 59 / 70 | 20 / 70 | |
| ANOVA | 0.48 | 0.739 | 0.977 | 0.923 | 0.511 | |||||
Abbreviations: ANOVA, analysis of variance; APOE, apolipoprotein E; BMI, body mass index; Lden index, day‐evening‐night sound average; NDVI, normalized difference vegetation index; NO2, nitrogen dioxide; PM2.5, fine particulate matter; TIV, total intracranial volume.
Notes: Continuous values displayed as mean (standard deviation). Discrete values in number of cases/total. TIV in cubic centimeters. Physical activity in mets (metabolic equivalents). ANOVA rows: P‐value of one‐way ANOVA of variables across pollutant terciles. (*) for significant ANOVAs at P < 0.05 uncorrected by multiple comparisons. Only TIV for NO2 and Lden and BMI for Lden showed significant differences across pollutant terciles. Those differences were disregarded (refer to main text for the rationale). Limit values of central tercile: NO2 = [52.8,60.6]; PM2.5 = [16.2,17.5]; Lden = [66,70] and NDVI = [0.19,0.22].