Table 3.
Comparison of sleep quality and its subscales between study groups.
| Variable (Score range) | Dark chocolate (n = 30) | Milk chocolate (n = 30) | P-value | ES | ||
|---|---|---|---|---|---|---|
| Global score (0–21) | ||||||
| Baseline | 8.4 ± 4.2 | 8.0 (4.8 to 11.0) | 8.4 ± 4.2 | 8.0 (5.0 to 12.0) | 0.988a | - |
| After 8 weeks | 7.3 ± 4.2 | 5.5 (4.8 to 10.0) | 7.6 ± 4.1 | 6.5 (5.0 to 10.3) | 0.546b | -0.07 |
| Subjective sleep quality (0–3) | ||||||
| Baseline | 1.3 ± 1.1 | 1.0 (0.8 to 2.0) | 1.2 ± 1.0 | 1.0 (0.0 to 2.0) | 0.815 b | - |
| After 8 weeks | 1.1 ± 1.1 | 1.0 (0.0 to 2.0) | 1.2 ± 1.1 | 1.0 (0.0 to 2.0) | 0.780 b | -0.09 |
| Sleep latency (0–3) | ||||||
| Baseline | 1.2 ± 0.8 | 1.0 (0.8 to 2.0) | 1.3 ± 1.0 | 1.0 (0.8 to 2.0) | 0.596 b | - |
| After 8 weeks | 1.1 ± 1.1 | 1.0 (0.0 to 1.3) | 1.3 ± 1.0 | 1.0 (0.8 to 2.0) | 0.145 b | -0.19 |
| Sleep duration (0–3) | ||||||
| Baseline | 1.8 ± 0.8 | 2.0 (1.0 to 2.0) | 1.7 ± 1.0 | 2.0 (1.0 to 2.3) | 0.863 b | - |
| After 8 weeks | 1.6 ± 0.9 | 2.0 (1.0 to 2.0) | 1.3 ± 0.8 | 1.5 (1.0 to 2.0) | 0.260 b | 0.35 |
| Sleep efficacy (0–3) | ||||||
| Baseline | 0.8 ± 1.2 | 0.0 (0.0 to 2.0) | 0.7 ± 1.1 | 0.0 (0.0 to 1.3) | 0.850 b | - |
| After 8 weeks | 0.6 ± 0.9 | 0.0 (0.0 to 1.0) | 0.6 ± 1.1 | 0.0 (0.0 to 1.0) | 0.715 b | 0.00 |
| Sleep disturbances (0–3) | ||||||
| Baseline | 1.6 ± 0.6 | 2.0 (1.0 to 2.0) | 1.5 ± 0.6 | 1.5 (1.0 to 2.0) | 0.720 b | - |
| After 8 weeks | 1.4 ± 0.6 | 1.0 (1.0 to 2.0) | 1.3 ± 0.6 | 1.0 (1.0 to 2.0) | 0.684 b | 0.17 |
| Use of sleep medication (0–3) | ||||||
| Baseline | 0.2 ± 0.8 | 0.0 (0.0 to 0.0) | 0.2 ± 0.7 | 0.0 (0.0 to 0.0) | 0.688 b | - |
| After 8 weeks | 0.1 ± 0.6 | 0.0 (0.0 to 0.0) | 0.2 ± 0.5 | 0.0 (0.0 to 0.0) | 0.655 b | -0.18 |
| Daytime dysfunction (0–3) | ||||||
| Baseline | 1.6 ± 0.8 | 2.0 (1.0 to 2.0) | 1.7 ± 0.9 | 2.0 (1.0 to 2.3) | 0.614 b | - |
| After 8 weeks | 1.4 ± 0.8 | 1.0 (1.0 to 2.0) | 1.7 ± 0.9 | 2.0 (1.0 to 2.0) | 0.134 b | -0.35 |
Data were presented as mean ± standard deviation or median (percentile 25 to percentile 75), a Independent t-test, b Mann–Whitney U test, ES: effect size (Cohen’s d).