Table 3. Presence of Coronary Artery Calcification (CARDIA Year 20 or Year 15) by Quartile of Baseline Mean Nighttime to Daytime Systolic BP Ratio (N=239).
| Quartile | % with CAC |
OR | 95% confidence interval |
p-value | Nonlinearity (quadratic) p-value |
|---|---|---|---|---|---|
| Crude (n/N)* | <0.001 | ||||
| Q1 (21/60) | 35.0 | 4.76 | 1.76-12.9 | 0.002 | |
| Q2 (9/63) | 14.3 | 1.47 | 0.49-4.42 | 0.49 | |
| Q3 (6/59) | 10.2 | 1.00 (ref) | |||
| Q4 (18/57) | 31.6 | 4.08 | 1.48-11.2 | 0.007 | |
|
Adjusted for age, sex, race, baseline smoker, BMI, and HDL-C |
0.038 | ||||
| Q1 | 4.49 | 1.48-13.6 | 0.008 | ||
| Q2 | 1.50 | 0.45-5.08 | 0.51 | ||
| Q3 | 1.00 (ref) | ||||
| Q4 | 2.81 | 0.90-8.72 | 0.07 | ||
|
Adjusted for Year 5 ASBP, ADBP, SDBP |
0.001 | ||||
| Q1 | 4.21 | 1.44-12.3 | 0.009 | ||
| Q2 | 1.23 | 0.39-3.83 | 0.72 | ||
| Q3 | 1.00 (ref) | ||||
| Q4 | 3.92 | 1.31-11.8 | 0.015 | ||
|
Adjusted for additional year 5 covariates† and CAC exam year |
0.012 | ||||
| Q1 | 5.76 | 1.53-21.8 | 0.01 | ||
| Q2 | 1.37 | 0.33-5.74 | 0.67 | ||
| Q3 | 1.00 (ref) | ||||
| Q4 | 6.19 | 1.38-27.8 | 0.017 | ||
|
Additionally-adjusted for smoking status in CAC year |
0.015 | ||||
| Q1 | 5.34 | 1.41-20.2 | 0.014 | ||
| Q2 | 1.21 | 0.29-5.11 | 0.80 | ||
| Q3 | 1.00 (ref) | ||||
| Q4 | 5.73 | 1.27-25.8 | 0.023 |
OR, odds ratio; ref, referent; ASBP, awake systolic blood pressure average; ADBP, awake diastolic blood pressure average; SDBP, sleep diastolic blood pressure average; CAC, coronary artery calcium.
*
n/N: No. of cases/Total number of subjects with known non-zero Agatston score
†
Adjusted for age, sex, race, education, BMI, baseline smoker, ASBP, ADBP, SDBP, serum cotinine level, LDL-C, HDL-C, known diabetes, known hypertension, baseline clinic systolic BP, baseline clinic diastolic BP, pack-years of tobacco, alcohol intake, physical activity, family history of hypertension, family history of diabetes, poor sleep quality during ABPM.