Table 5.

Relative Risk of DBP Nondipping at 7.4-Year Follow-up According to Sleep Quality.

Characteristics	Total sample, n	Incident nondipping, n(%)	RR (95% CI)
			Unadjusted	Adjusted
Insomnia
Yes	62	11(17.7)	1.5 (0.7, 3.2)	1.3 (0.5, 3.2)
No	124	15(12.1)	1.0 (Ref)	1.0 (Ref)
Missing	87
Difficulty falling asleep
Often/almost always	18	4(22.2)	1.9 (0.7, 5.5)	1.6 (0.5, 5.4)
Sometimes/less	198	23 (11.6)	1.0 (Ref)	1.0 (Ref)
Missing	57
Sleep latency, hours	273	36 (13.2)	0.5 (0.05, 3.7)	0.5 (0.05, 4.0)
Waking after sleep onset, per hour	273	36 (13.2)	0.9 (0.5, 1.7)	1.00 (0.5, 2.2)
Total sleep time
Tst< 6 h	91	9 (9.9)	0.7 (0.3, 1.7)	0.8 (0.3, 1.9)
6 h ≤TST <7h	104	14 (13.5)	1.0 (Ref)	1.0 (Ref)
7 h ≤TST <8h	62	8 (12.9)	1.0 (0.4, 2.3)	1.0 (0.4, 2.4)
TST≥ 8 h	16	5 (31.3)	2.3(0.8, 6.4)	2.1 (0.7, 6.7)
Sleep efficiency
Sleep efficiency ≥ 0.8	213	28 (13.2)	1.0 (Ref)	1.0 (Ref)
Sleep efficiency < 0.8	60	8 (13.3)	1.0 (0.5, 2.3)	1.2 (0.5, 2.8)

Abbreviations: CI, confidence interval; DBP: diastolic blood pressure RR, relative risk; tst, total sleep time.

Analysis adjusted for baseline age, sex, BMI at baseline and follow-up, current smoking, hypertension, alcohol consumption from the baseline visit; duration of follow-up; self-reported hours of weekly physical exercise, use of sedative medication, and whether or not an individual was on antihypertensive medication at any time during the follow-up time period, nap frequency, leg movements, and sleep disordered breathing (AHI).