Table 3

Incidence rates for type 2 diabetes by sleep duration at baseline

Baseline sleep duration
P*
≤6.5 h7.0–8.5 h9.0–9.5 h≥10.0 h
Control group
    Person-years of follow-up154747260319
    No. of diabetes events11362436
    Incidence per 100 person-years7.1 (4.0–12.9)4.8 (3.5–6.7)9.2 (6.2–13.8)11.3 (8.1–15.6)0.001
    HR, unadjusted1.51 (0.73–3.10)1.01.99 (1.20–3.31)2.43 (1.54–3.84)
    HR, adjusted1.51 (0.73–3.12)1.02.05 (1.25–3.38)2.88 (1.82–4.57)
    HR, adjusted1.68 (0.79–3.59)1.02.29 (1.38–3.80)2.74 (1.67–4.50)
Intervention group
    Person-years of follow-up126678467460
    No. of diabetes events8322114
    Incidence per 100 person-years6.3 (3.2–12.7)4.7 (3.3–6.7)4.5 (2.9–6.9)3.0 (1.8–5.1)0.377
    HR, unadjusted1.34 (0.58–3.10)1.00.93 (0.54–1.60)0.65 (0.35–1.21)
    HR, adjusted1.06 (0.46–2.46)1.00.99 (0.57–1.71)0.76 (0.40–1.44)
    HR, adjusted1.44 (0.59–3.53)1.01.10 (0.60–2.01)0.73 (0.34–1.56)
  • Data in parentheses are 95% CI.

  • *P value: log-rank test for equal incidence over sleep duration categories.

  • †Adjusted for age, sex, BMI, and study center.

  • ‡Adjusted for age, sex, BMI, study center, smoking, alcohol intake, hypertension medication, leisure-time physical activity at baseline, and 1-year change in body weight.