Table 1.

Baseline (2003–2005) characteristics of older men according to quartiles of amplitude and categories of acrophase in the MrOS Sleep study

	Amplitude				P	Acrophasea			P
	Q1	Q2	Q3	Q4		Early	Normal	Late
Age, years	78.1 (5.9)	76.8 (5.5)	75.8 (5.2)	74.8 (4.9)	<0.0001b	76.7 (5.3)	76.2 (5.5)	76.6 (5.7)	0.28b
Education: college or higher	53.2	60.1	56.1	53.0	0.07c	45.4	58.2	54.0	0.0002c
Married	79.8	83.6	86.4	85.4	0.01c	82.3	85.3	77.0	0.0007c
White	91.5	93.1	92.9	89.1	0.04c	94.3	91.3	90.4	0.13c
Smoking: former or current	61.6	56.8	59.3	62.3	0.47c	63.1	59.4	59.7	0.07c
Alcohol: ≥1 drink/week	46.9	54.0	51.9	59.4	<0.0001c	47.7	55.1	48.1	0.008c
Healthy diet score	−0.06 (1.02)	0.02 (1.05)	0.06 (1.04)	0.05 (0.98)	0.10b	−0.01 (1.02)	0.02 (1.02)	0.03 (1.01)	0.89b
BMI	27.9 (4.0)	27.2 (3.6)	26.8 (3.5)	26.7 (3.56)	<0.0001b	27.6 (3.9)	27.0 (3.6)	27.3 (3.9)	0.04b
Self-rated health: good/excellent	79.6	86.3	92.0	90.5	<0.0001c	86.0	88.2	82.8	0.02c
Physical activity score	117.9 (64.4)	139.2 (65.0)	157.3 (68.0)	172.0 (72.8)	<0.0001d	151.2 (73.5)	149.6 (69.6)	127.9 (70.4)	<0.0001d
Total sleep time, h	6.3 (1.5)	6.5 (1.1)	6.5 (1.1)	6.4 (1.1)	0.08d	6.3 (1.2)	6.4 (1.2)	6.3 (1.2)	0.003d
Sleep efficiency	0.75 (0.15)	0.79 (0.11)	0.80 (0.10)	0.79 (0.11)	<0.0001d	0.79 (0.12)	0.79 (0.12)	0.76 (0.12)	0.005d
Sleep midpoint	0301 h (59 min)	0248 h (57 min)	0247 h (52 min)	0248 h (55 min)	<0.0001d	0155 h (59 min)	0248 h (40 min)	0410 h (42 min)	<0.0001d
Disease history
CVD	43.2	37.7	34.5	30.2	<0.0001c	36.9	35.3	41.5	0.10c
Depression	10.2	5.8	4.6	4.8	0.0001c	6.0	5.8	9.3	0.07c
Cancer	29.3	30.8	30.2	22.6	0.004c	28.6	28.3	26.8	0.85c

Data are % or mean (SD).

^aAcrophase was categorized as early (mean − 1 SD, before 1304 h), normal (mean ± 1 SD, between 1304 h and 1529 h), and late (mean + 1 SD, after 1529 h).

^bP values were derived from ANOVA.

^cP values were derived from χ² test.

^dP values were derived from Kruskal-Wallis test.