Table 6 Association of tertiles of objectively assessed sleep duration with dementia over a mean follow-up of 6.4 (SD = 1.0; range = 0.1–7.4) years: accelerometer sub-study (N cases/N total = 111/3888).

From: Association of sleep duration in middle and old age with incidence of dementia

  N cases/N total Incidence rate per 1000 persons-years Model 1: adjusted for sociodemographic variablesa Model 1 + behavioural factorsb Model 1 + health-related factorsc Fully adjusted model
HR (95%CI) P valued HR (95%CI) P valued HR (95%CI) P valued HR (95%CI) P valued
Tertile 1: 1 h 16 min–6 h 13 min 53/1296 6.5 (4.7–8.2) 1.68 (1.08–2.63) 0.02 1.71 (1.09–2.67) 0.02 1.61 (1.03–2.53) 0.04 1.63 (1.04–2.57) 0.03
Tertile 2: 6 h 14 min–7 h 0 min 31/1296 3.8 (2.4–5.1) 1 (ref.)   1 (ref.)   1 (ref.)   1 (ref.)  
Tertile 3: 7 h 1 min–10 h 6 min 27/1296 3.3 (2.0–4.5) 0.87 (0.52–1.46) 0.60 0.87 (0.52–1.46) 0.61 0.78 (0.46–1.31) 0.35 0.78 (0.46–1.32) 0.36
  1. CI confidence intervals, HR hazard ratio, SD standard deviation, h hour, min minute.
  2. aHR estimated from a Cox regression adjusted for age (timescale), sex, ethnicity, education, and marital status.
  3. bAdditionally adjusted for alcohol consumption, physical activity, smoking status, and fruit and vegetable consumption.
  4. cAdditionally adjusted for BMI, hypertension, diabetes, cardiovascular disease, GHQ depression, and CNS medications.
  5. dTwo-sided P value for HR in comparison with the reference (ref.) category, without adjustment for multiple comparisons.