TABLE 6.
Effect of GlyNAC supplementation and withdrawal on cognition and physical function. OA received GlyNAC supplementation for 24 weeks, and GlyNAC was stopped for 12 weeks from week 24 to week 36. Data are reported as means ± SD and median (IQR). Means are significantly different at p < 0.05
| Cognition and physical function | Young adults: 0‐week | Older adults: 0‐week YA v OA 0‐week | Older adults: after 12‐weeks on GlyNAC OA‐0‐week v OA‐12‐weeks | Older adults: after 24‐weeks on GlyNAC OA‐0‐week v OA‐24‐weeks | Older adults: 36‐weeks (12‐weeks after stopping GlyNAC) OA‐24‐weeks v OA‐36‐weeks |
|---|---|---|---|---|---|
| Cognition | |||||
| Montreal cognitive assessment test | 29.4 ± 0.9 | 26.0 ± 2.2 | 28.6 ± 1.4 | 28.8 ± 0.7 | 27.5 ± 1.5 |
| 30.0 (1.5) | 26.5 (3.5) | 29.0 (3.0) | 29.0 (1.0) | 27.0 (1.5) | |
| p = 0.0046 | p = 0.0007 | p = 0.0023 | p = 0.038 | ||
| Trails A test (s) | 25.2 ± 8.4 | 45.2 ± 15.1 | 37.3 ± 10.6 | 32.1 ± 8.2 | 33.4 ± 10.4 |
| 25.4 (12.8) | 40.0 (22.8) | 34.4 (16.8) | 30.2 (11.7) | 29.5 (12.3) | |
| p = 0.004 | p = 0.012 | p = 0.003 | p = 0.58 | ||
| Trails B test (s) | 36.4 ± 8.7 | 71.0 ± 26.5 | 51.5 ± 15.2 | 48.6 ± 13.4 | 53.2 ± 23.3 |
| 36.1 (13.1) | 72.4 (24.1) | 54 (24.8) | 47.9 (22.4) | 47.0 (31.0) | |
| p = 0.007 | p = 0.023 | p = 0.016 | p = 0.38 | ||
| Verbal fluency test | 52.0 ± 6.7 | 44.0 ± 10.8 | 51.4 ± 10.7 | 52.1 ± 9.7 | 51.8 ± 13.4 |
| 53.5 (10) | 42.5 (14.5) | 54.0 (21.0) | 51.5 (17.5) | 48.5 (18.0) | |
| p = 0.059 | p = 0.0129 | p = 0.013 | p = 0.90 | ||
| Digital symbol substitution test (% completion) | 60.9 ± 9.1 | 41.3 ± 8.3 | 42.4 ± 8.2 | 43.6 ± 8.0 | 42.1 ± 7.1 |
| 61.4 (13.2) | 41.9 (10.5) | 44.1 (10.5) | 45.5 (8.2) | 43.9 (6.4) | |
| p = 0.006 | p = 0.38 | p = 0.013 | p = 0.013 | ||
| Digital symbol substitution test (% accuracy) | 99.4 ± 0.9 | 96.0 ± 3.1 | 98.7 ± 2.5 | 99.6 ± 1.2 | 97.5 ± 1.4 |
| 100.0 (1.4) | 99.6 (3.4) | 100.0 (1.9) | 100.0 (0.0) | 97.7 (1.4) | |
| p = 0.018 | p = 0.0038 | p = 0.015 | p = 0.0075 | ||
| Plasma BDNF concentration (ng/ml) | 36.3 ± 10.6 | 21.1 ± 4.2 | 25.3 ± 4.6 | 31.8 ± 5.6 | 27.8 ± 5.1 |
| 33.6 (12.9) | 21.4 (5.8) | 26.5 (5.7) | 33.0 (9.5) | 26.2 (3.9) | |
| p = 0.005 | p = 0.0002 | p = 0.0000 | p = 0.048 | ||
| Physical function | |||||
| Gait speed (m/s) | 1.4 ± 0.2 | 1.0 ± 0.1 | 1.3 ± 0.2 | 1.5 ± 0.2 | 1.2 ± 0.2 |
| 1.4 (0.2) | 1.0 (0.2) | 1.3 (0.3) | 1.5 (0.3) | 1.2 (0.2) | |
| p = 0.0061 | p = 0.0007 | p = 0.0002 | p = 0.035 | ||
| 6‐min rapid walk (m) | 723.1 ± 66.4 | 546.4 ± 38.3 | 578.3 ± 31.6 | 602.8 ± 43.4 | 562.1 ± 37.1 |
| 705.0 (80.5) | 542.0 (61.5) | 578.0 (32.5) | 606.0 (65.5) | 564.0 (43.0) | |
| p = 0.0009 | p = 0.077 | p = 0.0074 | p = 0.0007 | ||
| Grip strength, dominant hand (kg) | 35.3 ± 5.7 | 27.0 ± 9.7 | 29.7 ± 8.7 | 30.9 ± 9.2 | 27.3 ± 9.4 |
| 35.4 (9.5) | 24.5 (17.9) | 26.0 (13.1) | 27.2 (16.1) | 23.1 (18.3) | |
| p = 0.014 | p = 0.045 | p = 0.0056 | p = 0.018 | ||
| Grip strength, nondominant hand (kg) | 26.0 ± 2.6 | 23.7 ± 8.4 | 25.2 ± 7.3 | 26.6 ± 7.4 | 24.2 ± 7.6 |
| 26.0 (4.3) | 19.9 (14.7) | 21.7 (12.5) | 22.4 (13.6) | 19.9 (14.5) | |
| p = 0.013 | p = 0.08 | p = 0.004 | p = 0.0005 | ||