Table 2.
Prevalence of short sleep and cardiometabolic risk factors in 516 adolescents.
| Baseline | Follow-up | p-value | |
|---|---|---|---|
| Weekday sleep duration <6.5 hours per day | 7.3% (5.2–9.9) | 10.7% (8.2–13.7) | 0.105 |
| Weekday sleep duration <7 hours per day | 15.3% (12.3–18.8) | 20.5% (17.1–24.2) | 0.033* |
| Weekly average sleep duration <6.5 hours per day | 2.0% (1.0–3.6) | 5.1% (3.4–7.4) | 0.016* |
| Weekly average sleep duration <7 hours per day | 6.3% (4.4–8.8) | 11.0% (8.4–14.1) | 0.010* |
| Weekly average bedtime later than midnight | 16.2% (13.1–19.7) | 60.5% (56.2–64.8) | <0.001** |
| Overweight or obesity (BMI ≥ age- and sex-specific 85th percentile)a | 20.3% (17.0–24.1) | 23.4% (19.7–27.3) | 0.114 |
| General obesity (BMI ≥ age- and sex-specific 95th percentile)a | 8.3% (6.1–11.1) | 11.3% (8.7–14.4) | 0.034* |
| Central obesity (WC ≥ age- and sex-specific 90th percentile) | 16.9% (13.7–20.4) | 13.5% (10.6–16.8) | 0.034* |
| High triglyceride level | 4.8% (3.1–7.0) | 4.8% (3.1–7.0) | 0.999 |
| Low HDL-cholesterol level | 3.0% (1.7–4.9) | 4.8% (3.1–7.0) | 0.200 |
| High blood pressure level | 3.5% (2.1–5.5) | 5.1% (3.4–7.5) | 0.185 |
| High fasting plasma glucose level | 2.0% (1.0–3.6) | 0.6% (0.1–1.7) | 0.109 |
| Metabolic syndromeb | 0.6% (0.1–1.7) | 1.8% (0.8–3.4) | 0.146 |
Footnotes: Data are presented as prevalence (95% confidence interval). Boldface indicates statistical significance (*p < 0.05, **p < 0.001). We used McNemar’s test for within-subject changes. ΨOverweight or obesity was defined by Cook’s criteria with percentile curves based on a local population survey. aObesity was defined as body mass index (BMI) ≥ age- and sex-specific 95th percentile or ≥25 kg/m2 for those aged <18 or ≥18 years, respectively. The corresponding cut-offs for overweight were BMI ≥ age- and sex-specific 85th percentile or ≥23 kg/m2. bMetabolic syndrome was defined by the International Diabetes Federation criteria: central obesity (waist circumference [WC] ≥ age- and sex-specific 90th percentile or adult cut-offs) plus ≥2 of the following: triglyceride ≥1.7 mmol/L, high-density lipoprotein cholesterol (HDL-cholesterol) < 1.03 mmol/L, blood pressure ≥130/85 mmHg, fasting plasma glucose ≥5.6 mmol/L (adult criteria were adopted for adolescents aged 16 years or older).