Table 1. Characteristics of Sample at Baseline (CARDIA Year 5) by Dipping Ratio Quartiles (N=281).
| Quartile: Dipping Ratio* | ||||||
|---|---|---|---|---|---|---|
| Characteristic | Total | Q1: 0.72- 0.85 |
Q2: 85- 0.88 |
Q3: 0.88- 0.92 |
Q4: 0.92- 1.24 |
p- value |
| Age, mean (SD), years | 30.2 (3.7) |
30.8 (3.7) |
29.5 (3.5) |
29.9 (4.2) |
30.5 (3.2) |
0.14 |
| Age categories, % | ||||||
| 23-29 years | 43.4 | 32.9 | 56.3 | 44.3 | 40.0 | 0.04 |
| 30-36 years | 56.6 | 67.1 | 43.7 | 55.7 | 60.0 | |
| Male, % | 46.6 | 47.1 | 40.9 | 44.3 | 54.3 | 0.43 |
| Race categories, % | ||||||
| Black | 63.4 | 44.3 | 60.6 | 70.0 | 78.6 | 0.001 |
| White | 36.7 | 55.7 | 39.4 | 30.0 | 21.4 | |
| Education, mean (SD) | 13.5 | 13.5 | 13.6 | 13.5 | 13.3 | 0.90 |
| years | (2.0) | (2.4) | (1.9) | (1.9) | (1.8) | |
| BMI, mean (SD) kg/ m2 | 26.6 | 25.6 | 26.5 | 26.4 | 27.9 | 0.08 |
| (5.2) | (4.7) | (5.6) | (5.5) | (5.0) | ||
| BMI categories, % | ||||||
| Normal (<25 kg/m2) | 43.0 | 51.4 | 47.9 | 44.3 | 28.6 | 0.08 |
| Overweight (25-29 kg/m2) |
31.0 | 31.4 | 26.8 | 31.4 | 34.3 | |
| Obese (≥ 30 kg/m2) | 26.0 | 17.2 | 25.3 | 24.3 | 37.1 | |
| Current smoker, % | 28.1 | 32.9 | 21.1 | 17.1 | 41.4 | 0.005 |
| Pack-years of tobacco, mean (SD) |
2.6 (5.5) |
3.6 (7.0) |
2.5 (6.6) |
1.7 (3.3) |
2.5 (4.3) |
0.21 |
| Serum cotinine level (ng/ml) at year 0, mean (SD) |
64.8 (129) |
81.5 (157) |
50.0 (121) |
54.5 (113) |
73.4 (119) |
0.41 |
| High density lipoprotein cholesterol (mg/dl), mean (SD) |
50.8 (14) |
51.2 (15) |
52.1 (13) |
52.9 (15) |
46.9 (12) |
0.054 |
| Low density lipoprotein cholesterol (mg/dl), mean (SD) |
111.1 (30) |
117.3 (32) |
111.6 (31) |
106.4 (26) |
108.8 (31) |
0.17 |
| Known diabetes mellitus, % |
2.5 | 0 | 4.2 | 2.9 | 2.9 | 0.43 |
| Known hypertension, % |
7.1 | 5.7 | 9.9 | 4.3 | 8.6 | 0.55 |
| Glucose level (mg/dl) at year 7, mean (SD) |
92.7 (34) |
87.7 (6.9) |
91.1 (32.3) |
92.2 (24.2) |
100.9 (56.7) |
0.19 |
| Baseline clinic SBP (mm Hg), mean (SD) |
109.1 (11) |
108.3 (8.6) |
110.1 (11.8) |
108.5 (10.7) |
109.6 (11.2) |
0.73 |
| Baseline clinic DBP (mm Hg), mean (SD) |
73.1 (9.8) |
71.3 (9.8) |
74.0 (10.9) |
73.5 (8.3) |
73.5 (10.0) |
0.34 |
| Clinic pulse pressure (mm Hg), mean (SD) |
36.0 (8.2) |
37.1 (9.1) |
36.1 (7.8) |
35.0 (7.4) |
36.0 (8.5) |
0.54 |
| Alcohol intake (ML/day), mean (SD) |
11.6 (20.4) |
13.4 (22.9) |
9.6 (15.8) |
10.6 (20.3) |
12.6 (22.2) |
0.68 |
| Physical activity (Kcal/d), mean (SD) |
317.1 (267.2) |
326.4 (275.0) |
282.7 (267.7) |
354.3 (285.5) |
305.3 (239.0) |
0.43 |
| Family history of hypertension, % |
59.1 | 58.6 | 60.6 | 60.0 | 57.1 | 0.98 |
| Family history of diabetes, % |
16.0 | 18.6 | 14.1 | 12.9 | 18.6 | 0.71 |
| Poor sleep quality during ABPM, % |
16.4 | 18.6 | 16.9 | 12.9 | 17.1 | 0.82 |
*
Quartiles of mean nocturnal systolic BP/mean daytime systolic BP ratio: Q1: 0.7197-0.8454 (n=70); Q2: 0.8455-0.8809 (n=71); Q3: 0.8810-0.9203 (n=70); Q4: 0.9204-1.2358 (n=70)
CARDIA, Coronary Artery Risk Development in Young Adults Study; SBP, systolic blood pressure; DBP, diastolic blood pressure; ABPM, ambulatory blood pressure monitoring