Table 3.

Results of Cox regression analysis for associations between depressive symptom categories, diagnosed sleep disorders and heart disease

	Unadjusted model	Adjusted model
	HR (95% CI)	HR (95% CI)
Model 1: depression only
No/low depressive symptoms	Reference	Reference
Elevated depressive symptoms	1.34 (1.21–1.48)	1.40 (1.25–1.56)
Model 2: diagnosed sleep disorder only
No sleep disorder	Reference	Reference
Sleep disorder	1.65 (1.36–2.00)	1.52 (1.23–1.88)
Model 3: depression and diagnosed sleep disorder groups
No/low depressive symptoms and no sleep disorder	Reference	Reference
No/low depressive symptoms and sleep disorder	1.52 (1.20–1.93)	1.33 (1.03–1.73)
Elevated depressive symptoms and no sleep disorder	1.31 (1.18–1.45)	1.40 (1.25–1.57)
Elevated depressive symptoms and sleep disorder	2.31 (1.67–3.20)	2.60 (1.83–3.69)

Adjusted model is adjusted for the following variables: age, sex, education, ethnicity, smoking status, alcohol consumption, physical activity, cholesterol, diagnoses diabetes and diagnosed high blood pressure.

The assumption of proportional hazards was examined. Comparison of observed v. expected survival curves within each group suggested that the assumption of proportional hazards was met.