Table 5. Melatonin values in individuals with complete cervical SCI in comparison to healthy controls.
| Study | Circadian rhythm | Day-time pattern | Day-time values |
Night-time pattern | Night-time values |
|---|---|---|---|---|---|
| Kneisley et al.39 | Absent P > 0.2 |
↑ (08:00–24:00) P < 0.01 |
SCI: (5.9 ± 2.7 ng)/4 h C: (0.46 ± 0.52ng)/4 h |
→ (24:00–08:00) P > 0.2 |
SCI: (4.6 ± 2.2 ng)/4 h C: (3.3 ± 2.3 ng)/4 h |
| Li et al.38* | Absent P > 0.05 |
→ (14:00) P > 0.05 |
SCI: 11.6 ± 1.9 pg/ml C: 16.3 ± 1.9 pg/ml** |
↓ (02:00) P < 0.05 |
SCI: 11.6 ± 3.3 pg/ml C: 67.4 ± 15.6 pg/ml** |
| Papendorp et al.40 | Absent P > 0.01 |
→ (14:00) P > 0.001 |
SCI: 30.7 ± 18.5 pg/ml C: 22 ± 5 pg/ml** |
↓ (01:00) P < 0.001 ↓ (07:00) P < 0.001 |
SCI: 33.2 ± 10.9 pg/ml C: 106 ± 10 pg/ml SCI: 27.6 ± 13.2 pg/ml C: 55 ± 5 pg/ml** |
| Zeitzer et al.41 | Absent*** | ↓*** | SCI: *** C: NR |
↓*** | SCI: *** C: 70 pg/ml (peak value) |
| Verheggen et al.49 | Absent P > 0.05 |
NA | NA | ↓ (22:30, 23:00) P < 0.05 → (19:00–22:00) P > 0.05 |
SCI: 2.41 ± 1.25 pg/ml C: 10.62 ± 4.59 pg/ml SCI: 5.25 ± 3.72 pg/ml C: 2.59 ± 1.04 pg/ml |
| Spong et al.50 | NA | NA | NA | ↓**** | NA |
| Kostovski et al.51 | Absent**** | NA | NA | NA | NA |
| Fatima et al.52 | Present**** | → (12:00) P > 0.01 → (18:00) P > 0.01 |
SCI: 16.9 pg/ml C: 14.4 pg/ml** SCI: 19.3 pg/ml C: 23.7 pg/ml** |
↓ (24:00) P < 0.01 ↑ (06:00) P < 0.01 |
SCI: 49.3 ± 19.5 pg/ml C: 65.6 ± 10.6 pg/ml SCI: 25.1 ± 6.7 pg/ml C: 13.7 ± 6.9 pg/ml |
Day and night-time melatonin patterns are in comparison to healthy controls (↑ = increased as compared to healthy controls, → = no difference, ↓ = decreased in relation to healthy controls). The exact measurement values (SCI = complete cervical SCI and C = control) are given with the standard deviation. The time points for the day and night-time melatonin values are given in parentheses. NA, not assessed; NR, not reported.
*Cervical individuals included a heterogenous group with both complete and incomplete injuries.
**Melatonin values and/or standard deviation were not reported numerically, and were derived from inspection of figures if possible.
***Melatonin levels were not detectable in complete cervical SCI, precluding statistical analysis.
****Determination was made with no accompanying statistical analysis.