Table 1:
Baseline Characteristics of DASH-Sodium Study Participants (Total and by Early/Late Sleep Midpoint)1,2
| Characteristic | Overall | Early Midpoint (<2.40am) | Late Midpoint (>=2.40am) |
|---|---|---|---|
| Number of participants, n (%) | 106 | 47 (44) | 59 (56) |
| Sleep - Hours | |||
| Sleep Midpoint: Median (interquartile range) | 2.40 (1.30) | 2.00 (0.75) | 3.30 (0.85) |
| Sleep Midpoint: Mean (SD) | 2.40 (1.08) | 1.52 (0.49) | 3.35 (0.75) |
| Sleep Duration: Mean (SD) | 7.23 (1.28) | 6.53 (1.01) | 7.30 (1.42) |
| Bedtime: Mean (SD) | 23.12 (1.1) | 22.30 (0.75) | 23.54 (0.9) |
| Waketime: Mean (SD) | 6.24(1.4) | 5.24 (0.75) | 7.30 (1.1) |
| Age-group (n, %) | |||
| 18 to 30 | 0 (0) | 0 (0) | 0 (0) |
| 31 to 55 | 69 (65) | 31 (66) | 38 (64) |
| 56 to 65 | 28 (26) | 13 (28) | 15 (25) |
| >65 | 9 (8) | 3 (6) | 6 (10) |
| Sex (n, %) | |||
| Male | 46 (43) | 18 (38) | 28 (47) |
| Race/ethnicity (n, %) | |||
| Black/African-American | 54 (51) | 24 (51) | 30 (51) |
| Non-Hispanic White or Other | 52 (49) | 23 (49) | 29 (49) |
| Body mass index (kg/m2) | |||
| Mean (SD) | 29.28 (4.13) | 29.52 (4.68) | 29.08 (3.67) |
| World Health Organization Classification n (%) | |||
| <= 18.5 | 0 (0) | 0 (0) | 0 (0) |
| 18.5 – <= 25 | 12 (11) | 7 (15) | 5 (8) |
| >25 | 94 (89) | 40 (85) | 54 (92) |
| Physical activity: moderate n (%) | |||
| > Four Times a Week | 21 (20) | 6 (13) | 15 (25) |
| 2–4 Times a Week | 40 (38) | 22 (47) | 18 (31) |
| About Once a Week | 16 (15) | 8 (17) | 8 (14) |
| 2–3 Times a Month | 13 (12) | 4 (9) | 9 (15) |
| Rarely or Never | 16 (15) | 7 (15) | 9 (15) |
| Physical activity: vigorous n (%) | |||
| > Four Times a Week | 2 (2) | 0 (0) | 2 (3) |
| 2–4 Times a Week | 20 (19) | 9 (19) | 11 (19) |
| About Once a Week | 9 (8) | 1 (2) | 8 (14) |
| 2–3 Times a Month | 10 (9) | 3 (6) | 7 (12) |
| Rarely or Never | 65 (61) | 34 (72) | 31 (53) |
| Blood Pressure (mm Hg), Mean (SD) 4 | |||
| Systolic | 142.51 (14.80) | 142.98 (15.19) | 142.14 (14.61) |
| Diastolic | 94.13 (10.33) | 94.68 (10.94) | 93.69 (9.88) |
| Hypertension, n (%) | 8 (8) | 4 (9) | 4 (7) |
| Education, n (%) | |||
| High School Graduate or less | 19 (18) | 8 (17) | 11 (19) |
| Some College | 43 (41) | 19 (40) | 24 (41) |
| College Degree | 18 (17) | 7 (15) | 11 (19) |
| Post-graduate Work/Degree | 26 (25) | 13 (28) | 13 (22) |
| Household income (n, %) | |||
| < $30,000 | 30 (28) | 9 (19) | 21 (36) |
| $30,000–$60,000 | 44 (42) | 19 (40) | 25 (42) |
| > $ 60,000 | 30 (28) | 18 (38) | 12 (20) |
| Missing | 2 (2) | 1 (2) | 1 (2) |
| Smoker (n, %) | |||
| Never Smoked | 59 (56) | 28 (60) | 31 (53) |
| Former Smoker | 36 (34) | 15 (32) | 21 (36) |
| Current Smoker | 11 (9) | 4 (9) | 7 (12) |
| Diet Intervention n (%) | |||
| Dietary pattern | |||
| Control | 53 (50) | 21 (45) | 32 (54) |
| DASH-Combination Diet | 53 (50) | 26 (55) | 27 (46) |
| Sodium Level | |||
| Repeated Measures | |||
| High and Low/Medium | 88 (83) | 42 (89) | 46 (78) |
| Medium and Low | 1 (1) | 0 (0) | 1 (2) |
| One measure | |||
| High | 11 (10) | 4 (9) | 7 (12) |
| Medium | 4 (4) | 1 (2) | 3 (5) |
| Low | 2 (2) | 0 (0) | 2 (3) |
| Alcohol: No. of Drinks per Week, n (%) | |||
| 0 | 67 (63) | 29 (62) | 38 (64) |
| ≤ 5 | 28 (26) | 15 (32) | 13 (22) |
| 6 + | 11 (10) | 3 (6) | 8 (14) |
| No. of Metabolite Measurements, n (%) | |||
| 1 | 17 (16) | 5 (11) | 12 (20) |
| 2 | 89 (84) | 42 (89) | 47 (80) |
Values are means (SD) or n (%). DASH, Dietary Approaches to Stop Hypertension Trial.
1
Early and late midpoint defined by median midpoint sleep value for cohort.
2
Totals may not sum to 100 percent due to rounding.
3
Hypertension defined as an average systolic blood pressure of 140 to 159 mm Hg or an average diastolic blood pressure of 90 to 95 mm Hg during the three screening visits.
4
Blood pressure was the average of 3 screening measurements and 2 measurements during the run-in period.