Table 1.
Demographic and baseline characteristics of the participants (n = 39).
| Treatment Groups | |||
|---|---|---|---|
| Characteristics | Placebo (n = 21) | Niacin (n = 18) | p-Value |
| Sex, N (%) | |||
| Men | 19 (90.5) | 16 (88.9) | 1 a |
| Women | 2 (9.5) | 2 (11.1) | |
| Race/ethnicity, N (%) | |||
| Non-Hispanic White | 18 (85.7) | 18 (100) | 0.29 a |
| Non-Hispanic Black | 3 (14.3) | 0 (0) | |
| Veteran status, N (%) | |||
| Veterans | 15 (71.4) | 10 (55.6) | 0.5 a |
| Non-Veterans | 6 (28.6) | 8 (44.4) | |
| Age, mean (SD), y | 68.0 (10.7) | 68.2 (6.0) | |
| Duration of PD, mean (SD), y | 5.6 (4.2) | 6.0 (6.0) | |
| Age of Onset, mean (SD), y | 61.6 (10.9) | 63.3 (7.2) | |
| Disease Stage, N (%) | |||
| Early (H&Y < 2.5) | 14 (66.7) | 14 (77.8) | 0.68 a |
| Late (H&Y ≥ 2.5) | 7 (33.3) | 4 (22.2) | |
| Medications, mg/day | |||
| Sinemet intake, N (%) | 20 (95.2) | 15 (83.3) | 0.5 a |
| Levodopa dosage, mean (range) | 488.9 (300–1000) | 480.8 (200–800) | |
| H&Y staging, mean (range) | 2.2 (1.5–4) | 1.8 (0.5–4) | |
| UPDRS III Scores, mean (SD) | 22.4 (11.8) | 21.3 (15.8) | 0.99 b |
| Rigidity | 1.69 (2.23) | 1.5 (1.92) | 0.99 b |
| Resting Tremor | 4.52 (2.87) | 3.11 (2.82) | 0.34 b |
| Bradykinesia | 4.5 (4.6) | 4 (4.5) | 0.98 b |
| Cognitive flexibility | 73.38 (57.11) | 79.42 (62.46) | 0.99 b |
| Grip Strength, PSI | |||
| First affected hand | 305.09 (105.26) | 297.04 (125.68) | 0.99 b |
| Non (or later) affected hand | 300.43 (80.49) | 284.1 (123.09) | 0.98 b |
| FSS | 36.65 (13.02) | 40.28 (11.99) | 0.76 b |
| VAFS | 5.4 (2.23) | 5.17 (2.23) | 0.96 b |
| REM sleep, % | 15.19 (12.1) | 22.5 (13.36) | 0.32 b |
| GDS | 6.2 (5.87) | 7.89 (7.31) | 0.66 b |
| Stroop 3 trial | 8.13 (6.64) | 6.18 (7.92) | 0.81 b |
| Walk and Turn, s | 11.47 (3.46) | 10.33 (3.16) | 0.66 b |
| Valine, mg/dL | 229.33 (51.78) | 245.64 (33.42) | 0.69 b |
| Tyrosine, mg/dL | 73.93 (14.77) | 64.93 (16.28) | 0.35 b |
| Tryptophan, mg/dL | 60.87 (11.39) | 53.5 (10.81) | 0.23 b |
| Serotonin, mg/dL | 89.56 (60.5) | 84.21 (68.17) | 0.99 b |
| Phenylalanine, mg/dL | 74.47 (12.59) | 73.07 (9.74) | 0.98 b |
| Leucine, mg/dL | 136.87 (38.75) | 143.07 (27.71) | 0.95 b |
| Isoleucine, mg/dL | 72.14 (24.2) | 73.36 (15) | 0.99 b |
Values presented are proportions and mean (SD). a—differences were tested by chi-squared test, b—differences in means was test by t-test. UPDRS III–Unified Parkinson’s disease Rating Scale III, H&Y-Hoehn and Yahr Scale for Parkinson’s Disease Staging. Levodopa dosage was determined as mg/day. * Medication information on two subjects in the niacin group was not available.