Table 3. ORs for the prevalence of poor sleepa in each quintile of dietary rice, bread, and noodle intake as well as dietary glycemic index and glycemic load.
| Q1 | Q2 | Q3 | Q4 | Q5 | p b value | Continuousc | P value | |
| (lowest) | (middle) | (highest) | (1 SD increment) | |||||
| Rice | ||||||||
| Prevalence of poor sleep (%) | 39.0 | 30.7 | 28.0 | 28.0 | 26.0 | <0.001 | ||
| Age-, sex-adjusted OR | 1 | 0.69 | 0.60 | 0.59 | 0.54 | 0.001 | 0.85 | 0.010 |
| (95%CI) | (reference) | (0.51, 0.94) | (0.44, 0.82) | (0.43, 0.81) | (0.39, 0.74) | (0.76, 0.96) | ||
| Multivariate-adjusted ORd | 1 | 0.68 | 0.61 | 0.59 | 0.54 | 0.015 | 0.87 | 0.045 |
| (95%CI) | (reference) | (0.49, 0.93) | (0.43, 0.85) | (0.42, 0.85) | (0.37, 0.81) | (0.76, 1.00) | ||
| Bread | ||||||||
| Prevalence of poor sleep (%) | 27.7 | 30.1 | 29.5 | 31.3 | 33.3 | 0.284 | ||
| Age-, sex-adjusted OR | 1 | 1.13 | 1.10 | 1.19 | 1.31 | 0.545 | 1.06 | 0.312 |
| (95%CI) | (reference) | (0.82, 1.55) | (0.80, 1.51) | (0.87, 1.63) | (0.96, 1.78) | (0.95, 1.19) | ||
| Multivariate-adjusted ORd | 1 | 1.14 | 1.04 | 1.05 | 1.14 | 0.921 | 1.01 | 0.885 |
| (95%CI) | (reference) | (0.81, 1.60) | (0.74, 1.47) | (0.74, 1.50) | (0.79, 1.63) | (0.89, 1.14) | ||
| Noodle | ||||||||
| Prevalence of poor sleep (%) | 24.6 | 30.5 | 26.4 | 31.3 | 39.0 | <0.001 | ||
| Age-, sex-adjusted OR | 1 | 1.35 | 1.10 | 1.38 | 1.95 | <0.001 | 1.21 | 0.001 |
| (95%CI) | (reference) | (0.97, 1.87) | (0.79, 1.53) | (1.00, 1.91) | (1.42, 2.67) | (1.09, 1.35) | ||
| Multivariate-adjusted ORd | 1 | 1.25 | 1.05 | 1.31 | 1.82 | 0.002 | 1.21 | <0.001 |
| 95%CI) | (reference) | (0.90, 1.74) | (0.75, 1.47) | (0.94, 1.82) | (1.31, 2.51) | (1.09, 1.35) | ||
| Dietary GI | ||||||||
| Prevalence of poor sleep (%) | 35.4 | 34.3 | 24.7 | 28.9 | 28.5 | 0.016 | ||
| Age-, sex-adjusted OR | 1 | 0.96 | 0.59 | 0.73 | 0.72 | 0.006 | 0.82 | <0.001 |
| (95%CI) | (reference) | (0.71, 1.30) | (0.43, 0.81) | (0.54, 1.00) | (0.52, 0.99) | (0.74, 0.91) | ||
| Multivariate-adjusted ORd | 1 | 0.96 | 0.60 | 0.77 | 0.77 | 0.020 | 0.85 | 0.006 |
| (95%CI) | (reference) | (0.71, 1.31) | (0.44, 0.84) | (0.56, 1.07) | (0.55, 1.07) | (0.76, 0.95) | ||
| Dietary GL | ||||||||
| Prevalence of poor sleep (%) | 31.1 | 30.0 | 25.8 | 31.1 | 33.9 | 0.379 | ||
| Age-, sex-adjusted OR | 1 | 0.96 | 0.78 | 1.02 | 1.14 | 0.215 | 1.02 | 0.721 |
| (95%CI) | (reference) | (0.70, 1.32) | (0.56, 1.08) | (0.74, 1.40) | (0.83, 1.57) | (0.91, 1.14) | ||
| Multivariate-adjusted ORd | 1 | 0.98 | 0.79 | 1.09 | 1.27 | 0.092 | 1.07 | 0.284 |
| (95%CI) | (reference) | (0.71, 1.35) | (0.56, 1.11) | (0.77, 1.54) | (0.88, 1.82) | (0.95, 1.21) |
GI, glycemic index; GL, glycemic load, CI, confidence interval; SD, standard deviation; OR: odds ratio; PSQI-J: Japanese version of the Pittsburgh Sleep Quality Index; Q: quintile;
A PSQI-J global score >5.5 indicate poor sleep.
The χ 2 test was used to analyze the prevalence of poor sleep, and logistic regression analysis was used to assess the linear trends of ORs by using the median value of each quintile.
Differences of SD for rice, bread, noodles, dietary GI, and dietary GL were 69.1 g/1,000 kcal, 26.2 g/1,000 kcal, 32.8 g/1,000 kcal, 3.9, and 43.8/1,000 kcal, respectively.
Multivariate models included age (continuous), sex (continuous), Body mass index (kg/m2; continuous), smoking status (i.e., current, previous, or never; dummy variable), habitual exercise (MET-h/week; continuous), alcohol consumption (percentage of energy; continuous), frequency of breakfast consumption (i.e., 0–3, 4–6, or 7 days/week; dummy variable), rice intake (for the multivariate analyses of bread and noodles; continuous), bread intake (for the multivariate analyses of rice and noodles; continuous), and noodle intake (for the multivariate analyses of rice and bread; continuous).