Table 1. Characteristics of study population distributed by neighbourhood SES (n=3591).

		Neighbourhood SES
	Overall	Low	Medium	High
Total population, %*	100	21.2	46.1	32.7
Gender, %
Female	54.7	22.3	44.5	33.1
Male	45.3	19.6	48.2	32.2
Age in years, mean (SE)	53.5 (0.47)	52.7 (0.86)	54.3 (0.73)	57.1 (0.94)
Race/ethnicity, %
African-American	29.4	43.2	46.0	10.8
Hispanic	13.5	37.8	44.5	17.8
Caucasian	57.1	5.7	46.7	47.5
SES, %
Low	42.8	33.1	45.4	21.5
Medium	44.3	14.1	47.4	38.6
High	12.9	5.4	45.0	49.6
Marital status, %
Married	47.9	17.9	48.8	33.4
Divorced	27.0	24.1	43.7	32.2
Single/other	25.1	24.3	44.4	31.3
Sleep duration in Sleep duration category, %	6.6 (0.04)	6.4 (0.08)	6.6 (0.07)	6.9 (0.09)†
hours, mean (SE)
Very short (<5 h)	9.1	15.5	10.0	3.7
Short (5–6.9 h)	36.7	40.5	36.9	33.9
Normative (7–8.9 h)	47.3	36.2	46.6	55.5
Long (≥9 h)	6.9	7.8	6.4	6.9

^*Per cents are weighted.

^†p<0.0001 from multilevel model.

SES, socioeconomic status.