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).

	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

CI confidence intervals, HR hazard ratio, SD standard deviation, h hour, min minute.

^aHR estimated from a Cox regression adjusted for age (timescale), sex, ethnicity, education, and marital status.

^bAdditionally adjusted for alcohol consumption, physical activity, smoking status, and fruit and vegetable consumption.

^cAdditionally adjusted for BMI, hypertension, diabetes, cardiovascular disease, GHQ depression, and CNS medications.

^dTwo-sided P value for HR in comparison with the reference (ref.) category, without adjustment for multiple comparisons.