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.
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