Table 1.
Baseline characteristics of the study participants, overall and by vitamin D dose allocationa
| Vitamin D supplementation | Overall N = 221 | Low dose N = 111 | High dose N = 110 |
|---|---|---|---|
| N (%) or Mean ± SD | |||
| Overall | Low dose | High dose | |
| Sex, female/male N | 122/99 | 59/52 | 63/47 |
| Age, y | 71.1 ± 4.7 | 71.0 ± 4.7 | 71.2 ± 4.8 |
| BMI | 30.2 ± 4.4 | 29.7 ± 4.6 | 30.6 ± 4.4 |
| Current smoker | 53 (24) | 27 (24) | 26 (24) |
| Current alcohol use | 17 (8) | 10 (9) | 7 (6) |
| Comorbidities | N (%) | ||
| Prediabetes | 153 (69) | 75 (67) | 78 (71) |
| Hypertensive (on physical exam)b | 143 (65) | 65 (59) | 78 (71) |
| Dyslipidemia (on baseline testing)c | 142 (64) | 71 (63) | 71 (65) |
| On lipid-lowering drug | 66 (30) | 34 (30) | 32 (29) |
| Participants with comorbiditiesd | 170 (77) | 85 (76) | 85 (77) |
| 1 Comorbidity | 68 (31) | 35 (31) | 33 (30) |
| 2 Comorbidities | 81 (36) | 42 (38) | 39 (35) |
| ≥3 Comorbidities | 21 (9) | 8 (7) | 13 (12) |
| Hypertension status | |||
| Treated with medications for hypertension by self-report | 106 (48) | 52 (46) | 54 (49) |
| −BP ≥130/80, treated | 68 (31) | 29 (26) | 39 (35) |
| −BP < 130/80, treatedb | 38 (17) | 23 (20) | 15 (14) |
| BP ≥ 130/80b, not being treated | 75 (34) | 36 (32) | 39 (36) |
| Hypertension medication type | |||
| ACE inhibitors | 19 (9) | (9) | 11 (10) |
| ARBs | 19 (9) | 8 (9) | 11 (10) |
| β-Blockers | 35 (16) | 14 (16) | 20 (18) |
| Calcium channel blockers | 14 (6) | 10 (6) | 4 (4) |
| Thiazide diuretics | 19 (9) | 7 (9) | 12 (11) |
| SBP, mm Hg | 128.5 ± 16.3 | 127.1 ± 16.2 | 130 ± 16.3 |
| DBP, mm Hg | 74.7 ± 10.6 | 74.2 ± 10.5 | 75.3 ± 10.7 |
| Mean arterial blood pressure, mm Hge | 92.6 ± 11.3 | 91.8 ± 11.4 | 93.5 ± 11.2 |
| Pulse pressure, mm Hgf | 53.8 ± 12.4 | 52.9 ± 11.5 | 54.7 ± 13.2 |
| Mean heart rate, beats/min | 69.3 ± 8.3 | 68.7 ± 8.0 | 69.9 ± 8.5 |
| Serum 25OHD, ng/mL | 20.4 ± 7.4 | 20.0 ± 7.0 | 20.9 ± 8.2 |
| Calcium, mg/dL | 9.5 ± 0.4 | 9.4 ± 0.4 | 9.5 ± 0.4 |
| Creatinine, mg/dL | 0.8 ± 0.2 | 0.8 ± 0.2 | 0.8 ± 0.2 |
| GFRg | 81.3 ± 13.0 | 81.7 ± 85.9 | 80.9 ± 12.8 |
| CKD3ah | 18 (8) | 11 (10) | 7 (6) |
P = independent t test for continuous variables and chi-square for categorical variables between the two doses were not significant for any of the variables listed in the table.
Abbreviations: 25OHD, 25-hydroxyvitamin D; ACE, angiotensin-converting enzyme; ARB, angiotensin receptor blocker; BMI, body mass index; BP, blood pressure; CKD, chronic kidney disease; DBP, diastolic blood pressure; GFR, glomerular filtration rate; SBP, systolic blood pressure.
a There was no significant difference in any of the baseline characteristics by treatment group.
b Hypertensive was defined as SBP of 130 mm Hg or greater and/or DBP of 80 mm Hg or greater.
c Total cholesterol greater than 130 mg/dL.
d Comorbidities include cardiovascular disease, coronary artery disease, congestive heart failure, hypertension, and hypercholesterolemia.
e Mean arterial pressure was defined as one-third SBP + two-thirds DBP.
f Pulse pressure was defined as the difference between SBP and DBP.
g Estimated with the use of the CKD–Epidemiology Collaboration equation.
h GFR between 45 and 59.