Table 1.
Population Characteristics and Cognitive Test Scores at Baseline and Follow-up in the Newcastle 85+ Study by Quartile of RBC Folate Concentration
| Q1, <612 nmol/L | Q2, 612–870 nmol/L | Q3, 870–1280 nmol/L | Q4, >1280 nmol/L | P∗ | |
|---|---|---|---|---|---|
| Men, % (n) | 41 (77) | 38 (72) | 40 (75) | 38 (72) | .86 |
| BMI, mean (SD), kg/m2 | 24.2 (4.3) | 24.7 (4.5) | 24.3 (4.1) | 24.4 (4.3) | .78† |
| APOE ε4 carriers, % (n) | 32 (49) | 17 (25) | 30 (47) | 28 (42) | .02 |
| Plasma vitamin B12, pmol/L | 201 (135–280) | 216 (159–275) | 259 (193–371) | 278 (205–391) | <.001 |
| tHcy, μmol/L | 19.9 (16.3–24.6) | 18.3 (14.9–22.9) | 15.6 (13.0–19.6) | 13.8 (11.1–17.4) | <.001 |
| Alcohol drinkers, % (n) | 70 (92) | 73 (94) | 80 (96) | 66 (89) | .10 |
| Smokers, % (n) | 9 (16) | 4 (8) | 4 (8) | 5 (10) | .35 |
| Physical activity, high, % (n) | 38 (71) | 33 (62) | 34 (63) | 37 (68) | .75 |
| Education ≥12 y, % (n) | 11 (20) | 11 (20) | 14 (25) | 14 (26) | .18 |
| History of cardiovascular disease, % (n) | 45 (84) | 57 (108) | 66 (123) | 63 (119) | <.001 |
| Diabetes type 1 or 2, % (n) | 9 (16) | 16 (31) | 13 (25) | 17 (32) | .08 |
| Hypertension, % (n) | 54 (100) | 59 (112) | 54 (101) | 65 (122) | .12 |
| Renal impairment, % (n) | 20 (38) | 26 (49) | 22 (41) | 28 (52) | .36 |
| Depression, severe, % (n) | 4 (7) | 10 (19) | 11 (19) | 9 (16) | .25 |
| Global cognition (SMMSE) | |||||
| Baseline | 27 (24–29) | 28 (25–29) | 28 (25–29) | 28 (25–29) | .17 |
| Impaired, ≤25, % (n) | 31 (58) | 25 (48) | 26 (49) | 25 (48) | .52 |
| 3 y | 27 (23–29) | 28 (24–29) | 26 (23–29) | 27 (25–29) | .19 |
| Impaired, ≤25, % (n) | 37 (41) | 35 (35) | 40 (48) | 25 (27) | .10 |
| 5 y | 28 (23–29) | 27 (23–29) | 27 (23–28) | 28 (25–29) | .17 |
| Impaired, ≤25, % (n) | 32 (26) | 37 (27) | 43 (33) | 26 (21) | .16 |
| Focused attention (PoA, ms) | |||||
| Baseline | 1499 (1341–1691) | 1494 (1371–1752) | 1484 (1360–1719) | 1473 (1341–1667) | .54 |
| 1.5 y | 1546 (1398–1745) | 1538 (1377–1740) | 1533 (1399–1731) | 1515 (1366–1718) | .84 |
| 3.0 y | 1594 (1409–1777) | 1567 (1378–1775) | 1550 (1420–1782) | 1490 (1367–1688) | .16 |
| Sustained attention (CoA, ms) | |||||
| Baseline | 87.8 (80.7–91.4) | 87.5 (80.8–91.0) | 85.7 (77.0–91.0) | 87.7 (82.3–91.3) | .20 |
| 1.5 y | 86.6 (79.4–90.4) | 88.0 (81.9–91.6) | 87.0 (78.4–90.5) | 86.5 (80.8–90.9) | .24 |
| 3.0 y | 86.7 (81.1–91.0) | 86.8 (79.4–90.7) | 86.4 (78.6–90.7) | 87.0 (82.2–91.5) | .73 |
| RTV | |||||
| Baseline | 59.1 (50.6–71.4) | 61.2 (54.6–71.7) | 61.5 (53.2–73.1) | 57.6 (50.3–68.6) | .06 |
| 1.5 y | 60.0 (53.8–71.0) | 60.0 (52.1–68.2) | 60.2 (52.2–72.0) | 57.6 (52.1–67.0) | .68 |
| 3.0 y | 59.9 (50.8–70.0) | 59.8 (49.4–69.6) | 61.4 (51.8–72.3) | 59.3 (50.3–66.7) | .60 |
Q, quartile.
Lower scores in the PoA and RTV, and higher scores in CoA reflect better performance. Continuous variables are presented as medians and IQR unless otherwise stated. History of cardiovascular disease includes cardiac, cerebrovascular, and peripheral vascular diseases.
∗
No quartile difference by χ2 for categorical or by Kruskal-Wallis test for nonparametric continuous variables.
†
No BMI difference by 1-way analysis of variance.