Table 1. Selected baseline characteristics of NHANES 2005–06 participants by sleep duration categories (n = 2,459)1 , 2.
| Sleep duration categories | ||||||||
| (n = 114) | (n = 775) | (n = 1307) | (n = 173) | |||||
| Very short <5 h | Short 5–6 h | Normal 7–8 h | Long ≥9 h | |||||
| Mean, % | (SE) | Mean, % | (SE) | Mean, % | (SE) | Mean, % | (SE) | |
| Socio-demographic, lifestyle and health-related factors | ||||||||
| Age (y) | 45.3 | (1.6) | 45.1 | (0.9) | 46.0 | (0.9) | 47.5 | (2.1) |
| Race/ethnicity, %4 | ||||||||
| Non-Hispanic White | 56.3 | (7.5) | 67.8 | (2.9) | 77.3 | (2.5) | 70.8 | (4.6) |
| Non-Hispanic black | 25.3 | (6.2) | 14.8 | (2.7) | 6.3 | (1.1) | 11.4 | (3.0) |
| Mexican-American | 6.3 | (1.8) | 9.0 | (1.1) | 6.9 | (1.0) | 7.1 | (1.6) |
| Other ethnicity | 12.0 | (4.0) | 8.5 | (1.5) | 9.0 | (1.4) | 10.7 | (2.4) |
| Married, %4 | 52.8 | (4.9) | 60.5 | (2.5) | 67.3 | (1.8) | 62.6 | (4.9) |
| Education, %4 | ||||||||
| <High School | 4.6 | (1.6) | 5.3 | (1.0) | 4.6 | (0.9) | 7.2 | (1.9) |
| High School | 48.6 | (4.7) | 36.0 | (3.4) | 30.3 | (2.5) | 40.9 | (3.8) |
| >High School | 46.8 | (4.6) | 58.6 | (3.5) | 65.1 | (2.6) | 51.9 | (4.1) |
| Poverty Income Ratio, %4 | ||||||||
| <100% | 16.4 | (4.1) | 9.9 | (1.5) | 7.1 | (0.9) | 14.0 | (3.1) |
| 100%-<200% | 28.4 | (6.0) | 17.9 | (2.0) | 17.3 | (1.4) | 30.0 | (4.4) |
| ≥200% | 55.2 | (6.5) | 72.2 | (2.9) | 75.6 | (2.0) | 59.0 | (4.7) |
| Smoking status, %4 | ||||||||
| Never smoker | 35.6 | (4.9) | 48.4 | (2.1) | 55.3 | (2.5) | 56.5 | (5.4) |
| Former smoker | 14.4 | (5.8) | 25.5 | (1.6) | 26.4 | (1.8) | 19.5 | (4.0) |
| Current smoker | 50.0 | (7.1) | 26.2 | (2.3) | 18.3 | (1.5) | 24.0 | (4.3) |
| Physical activity, Mets.hr.wk−1 | 5.2 | (1.0)4 | 7.6 | (0.7) | 7.9 | (0.5) | 6.4 | (1.1) |
| Body mass index, kg.m−2 | 30.2 | (0.7)4 | 29.6 | (0.3)4 | 27.9 | (0.4) | 28.5 | (0.7) |
| Serum total cholesterol, mg/dL | 204.8 | (5.3) | 199.4 | (2.0) | 200.2 | (1.4) | 200.6 | (2.1) |
| History of selected chronic conditions | ||||||||
| Type 2 diabetes, %3 | 16.3 | (4.5) | 8.2 | (1.0) | 6.5 | (0.8) | 7.0 | (3.1) |
| Cardiovascular disease, %3 | 12.3 | (3.6) | 7.4 | (1.3) | 5.5 | (0.9) | 12.7 | (3.8) |
| Cancer, %3 | 9.9 | (2.9) | 4.9 | (0.8) | 7.8 | (0.5) | 11.4 | (3.4) |
| Anti-depressant medication use, % yes4 | 10.6 | (3.7) | 8.3 | (1.6) | 10.6 | (0.7) | 20.9 | (2.7) |
| Sleep outcome variables | ||||||||
| Factor 1: Poor sleep-related daytime dysfunction | +0.21 | (0.19) | +0.09 | (0.04)4 | −0.07 | (0.02) | +0.01 | (0.11) |
| Factor 2: Sleepiness | +0.65 | (0.11)4 | +0.19 | (0.05)4 | −0.07 | (0.02) | +0.09 | (0.08) |
| Factor 3: Sleep disturbance | +0.71 | (0.14)4 | +0.17 | (0.04)4 | −0.13 | (0.03) | −0.11 | (0.08) |
| Sleep duration (h per night) | +3.67 | (0.07)4 | +5.74 | (0.01)4 | +7.45 | (0.02) | +9.39 | (0.07)4 |
| Sleep disorders, %4 | 22.2 | (6.3) | 8.2 | (1.2) | 4.9 | (0.8) | 6.1 | (3.5) |
| Insomnia only, % | 13.7 | (0.5) | 4.8 | (0.8) | 3.9 | (0.8) | 5.5 | (3.4) |
| Sleep apnea only, % | 2.2 | (1.7) | 1.2 | (0.5) | 0.4 | (0.2) | 0.0 | (0.0) |
| Restless leg syndrome only, % | 0.8 | (0.8) | 0.4 | (0.2) | 0.0 | (0.0) | 0.0 | (0.0) |
| All others and multiple, % | 0.0 | (0.0) | 0.8 | (0.4) | 0.0 | (0.0) | 0.0 | (0.0) |
| Nutritional biomarkers | ||||||||
| Retinol, µmol/L | 2.11 | (0.07) | 2.10 | (0.03) | 2.14 | (0.02) | 2.02 | (0.08) |
| Serum retinyl esters, µmol/L | 0.10 | (0.01) | 0.11 | (0.00)4 | 0.12 | (0.00) | 0.12 | (0.01) |
| Total retinol+retinyl esters, µmol/L | 2.22 | (0.08) | 2.21 | (0.03) | 2.26 | (0.02) | 2.14 | (0.08) |
| α-Carotene, µmol/L | 0.06 | (0.01)4 | 0.08 | (0.00)4 | 0.10 | (0.01) | 0.09 | (0.01) |
| β-Carotene, µmol/L | 0.24 | (0.02)4 | 0.35 | (0.02)4 | 0.43 | (0.02) | 0.41 | (0.06) |
| β-Cryptoxanthin, µmol/L | 0.16 | (0.01) | 0.17 | (0.01)4 | 0.19 | (0.01) | 0.18 | (0.01) |
| Lutein+zeaxanthin, µmol/L | 0.28 | (0.01) | 0.28 | (0.01) | 0.30 | (0.01) | 0.29 | (0.02) |
| Lycopene, µmol/L | 0.45 | (0.02) | 0.47 | (0.01) | 0.45 | (0.01) | 0.46 | (0.02) |
| Total carotenoids, µmol/L | 1.19 | (0.05)4 | 1.35 | (0.04)4 | 1.47 | (0.03) | 1.42 | (0.10) |
| Vitamin E, µmol/L | 28.6 | (1.4) | 28.2 | (0.7)3 | 30.2 | (0.4) | 29.2 | (1.1) |
| Vitamin C, µmol/L | 47.7 | (4.1)3 | 50.0 | (1.4)4 | 56.7 | (1.0) | 57.6 | (3.1) |
| Folate, nmol/L | 25.7 | (1.5)4 | 28.9 | (1.1)4 | 32.6 | (0.7) | 34.4 | (2.4) |
| Vitamin B-12, pmol/L | 629.6 | (231.5) | 394.0 | (11.5) | 402.4 | (9.2) | 373.4 | (16.0) |
| tHcy, µmol/L | 9.2 | (0.3)4 | 8.4 | (0.1) | 8.1 | (0.1) | 7.8 | (0.2) |
| 25(OH)D, ng/mL | 18.0 | (0.8)4 | 21.4 | (0.5)3 | 22.5 | (0.4) | 23.0 | (1.1) |
| Dietary Intakes | ||||||||
| Total Energy Intake, kcal/d | 2,182 | (126) | 2,375 | (51)3 | 2,241 | (38) | 2,100 | (83)3 |
| Alcohol intake, g/d | 10.0 | (2.6) | 11.2 | (1.2) | 10.3 | (1.1) | 8.2 | (1.5) |
| Caffeine, mg/d | 302.6 | (39.6)4 | 191.2 | (8.3) | 177.9 | (5.5) | 155.7 | (12.3) |
| Fiber, g/d | 13.7 | (1.0)4 | 15.9 | (0.3)3 | 16.7 | (0.4) | 14.3 | (0.7)4 |
| α-carotene, µg/d | 250.0 | (39.7)4 | 369.0 | (38.8)3 | 464.0 | (30.5) | 402.1 | (67.2) |
| β-carotene, µg/d | 1,378.1 | (176.0)4 | 1,915.4 | (103.8)4 | 2,437.1 | (124.4) | 1,871.7 | (216.2) |
| β-Cryptoxanthin, µg/d | 135.4 | (24.6) | 125.8 | (10.1) | 133.6 | (6.5) | 114.5 | (91.2) |
| Lutein+zeaxanthin, µg/d | 1,091.5 | (140.6)4 | 1,336.3 | (96.7)3 | 1,619.3 | (95.0) | 1,149.5 | (130.4)4 |
| Lycopene, µg/d | 5,008.8 | (1,146) | 5,569.7 | (316.3) | 5,864.8 | (298.3) | 4,777.7 | (444.3) |
| Total carotenoids, µg/d | 8,992 | (1,363)3 | 10,863 | (460)4 | 12,492 | (418) | 9,7854 | (753) |
| vitamin C, mg/d | 86.7 | (9.3) | 84.2 | (4.0) | 92.3 | (3.1) | 76.53 | (4.8) |
| vitamin E, mg/d | 6.6 | (0.6)3 | 7.6 | (0.2) | 7.8 | (0.2) | 6.7 | (0.2)4 |
| n-3 HUFA, g/d | 0.12 | (0.02) | 0.14 | (0.02) | 0.17 | (0.01) | 0.16 | (0.03) |
| Folate, µg/d | 362.0 | (21.3)4 | 413.0 | (8.0) | 434.7 | (8.9) | 386.44 | (10.2) |
| Vitamin B-12, µg/d | 4.7 | (0.4)4 | 5.7 | (0.3) | 5.9 | (0.2) | 5.3 | (0.2)3 |
| Dietary supplement use, past 30 d | ||||||||
| None | 60.8 | (5.1) | 41.0 | (2.2) | 35.9 | (1.9) | 30.5 | (3.0) |
| One | 16.5 | (4.6) | 29.3 | (2.0) | 28.1 | (1.8) | 33.8 | (4.1) |
| Two or more | 22.6 | (3.8) | 29.7 | (2.2) | 36.0 | (1.7) | 35.7 | (4.3) |
| Fruits and vegetable intake, cup equivalent/d | 2.31 | (0.20) | 2.54 | (0.10)3 | 2.72 | (0.08) | 2.233 | (0.15) |
Abbreviations: 25(OH)D = 25-hydroxyvitamin D; n-3 HUFA = n-3 highly unsaturated fatty acids; NHANES = National Health and Nutrition Examination Survey; SE = Standard error; tHcy = Total homocysteine.
1
Values are mean±SE or percent±SE. Sampling design complexity is taken into account in all analyses. This analysis is done among participants with complete data for sleep quality variables and other key variables of interest (n = 2,459).
2
P-value was based on design-based F-test if row variable is categorical and t-test if row variable is continuous (comparing normal sleep to each of the other categories).
3
P<0.05.
4
P<0.01 for null hypothesis of no difference by sleep duration category.