Table 2.
Effect of Calcium plus Vitamin D on Mean Difference (95% CI) in blood pressure change over the course of the trial overall and in subgroups for 36,189 participants with measured blood pressures at randomization.
| Mean Difference in Blood Pressure Change over Follow-up: Overall and by Baseline Subgroups* | ||||||||
|---|---|---|---|---|---|---|---|---|
| Systolic Blood Pressure | Diastolic Blood Pressure | |||||||
| Overall | Mean Difference |
Lower | Upper | P-value† | Mean Difference |
Lower | Upper | P-value† |
| Overall effect of Calcium/Vitamin D | 0.22 | −0.05 | 0.49 | 0.11‡ | 0.11 | −0.04 | 0.27 | 0.14‡ |
| Subgroup | ||||||||
| Age at screening, years | 0.95 | 0.58 | ||||||
| 50-59 | 0.22 | −0.22 | 0.66 | 0.10 | −0.15 | 0.36 | ||
| 60-69 | 0.18 | −0.21 | 0.58 | 0.06 | −0.17 | 0.28 | ||
| 70-79 | 0.31 | −0.33 | 0.95 | 0.29 | −0.08 | 0.66 | ||
| Ethnicity | 0.79 | 0.67 | ||||||
| White | 0.17 | −0.12 | 0.46 | 0.10 | −0.06 | 0.27 | ||
| Black | 0.46 | −0.44 | 1.35 | 0.07 | −0.45 | 0.58 | ||
| Hispanic | 0.97 | −0.37 | 2.30 | 0.22 | −0.55 | 0.98 | ||
| Asian or Pacific Islander | 0.20 | −1.68 | 2.09 | 0.85 | −0.23 | 1.94 | ||
| Other/Unknown | −0.13 | −2.25 | 2.00 | −0.30 | −1.52 | 0.93 | ||
| Education | 0.48 | 0.18 | ||||||
| High school diploma or less | 0.50 | −0.05 | 1.05 | 0.33 | 0.01 | 0.64 | ||
| Some school after high school | 0.20 | −0.23 | 0.62 | 0.14 | −0.11 | 0.39 | ||
| College degree or higher | 0.07 | −0.37 | 0.51 | −0.05 | −0.31 | 0.20 | ||
| Blood pressure, mm Hg§ | 0.21 | 0.28 | ||||||
| <120/80 | −0.02 | −0.40 | 0.36 | 0.13 | −0.11 | 0.37 | ||
| 120-139/80-89 | 0.08 | −0.26 | 0.42 | −0.03 | −0.25 | 0.18 | ||
| ≥ 140/90 | 0.52 | 0.03 | 1.01 | 0.26 | −0.05 | 0.57 | ||
| Hypertensive at enrollment | 0.09 | 0.18 | ||||||
| No | −0.01 | −0.37 | 0.34 | 0.01 | −0.20 | 0.21 | ||
| Yes∥ | 0.45 | 0.06 | 0.83 | 0.22 | −0.01 | 0.44 | ||
| BMI, kg/m2§ | 0.73 | 0.91 | ||||||
| <25 | 0.31 | −0.20 | 0.81 | 0.06 | −0.23 | 0.35 | ||
| 25 - <30 | 0.07 | −0.38 | 0.52 | 0.15 | −0.11 | 0.40 | ||
| ≥ 30 | 0.29 | −0.15 | 0.74 | 0.12 | −0.14 | 0.37 | ||
| Physical activity, MET hours/week | 0.26 | 0.68 | ||||||
| < 3.00 | 0.61 | 0.12 | 1.10 | 0.26 | −0.02 | 0.55 | ||
| 3.00 - < 11.75 | 0.03 | −0.46 | 0.52 | 0.09 | −0.19 | 0.37 | ||
| ≥ 11.75 | 0.30 | −0.18 | 0.79 | 0.14 | −0.14 | 0.42 | ||
| Total calcium intake, mg/day¶ | 0.62 | 0.80 | ||||||
| < 600 | −0.11 | −0.73 | 0.50 | −0.01 | −0.37 | 0.34 | ||
| 600-799 | 0.24 | −0.47 | 0.95 | 0.26 | −0.15 | 0.67 | ||
| 800-1199 | 0.23 | −0.29 | 0.76 | 0.12 | −0.18 | 0.42 | ||
| ≥ 1200 | 0.39 | −0.03 | 0.82 | 0.09 | −0.16 | 0.33 | ||
| Dietary calcium, mg/day | 0.53 | 0.96 | ||||||
| < 400 | −0.03 | −0.77 | 0.71 | 0.08 | −0.35 | 0.50 | ||
| 400-599 | 0.53 | −0.05 | 1.12 | 0.07 | −0.27 | 0.40 | ||
| 600-1199 | 0.11 | −0.28 | 0.49 | 0.09 | −0.13 | 0.31 | ||
| ≥ 1200 | 0.41 | −0.24 | 1.07 | 0.19 | −0.19 | 0.56 | ||
| Total vitamin D intake, IU/day¶ | 0.15 | 0.65 | ||||||
| <200 | 0.21 | −0.23 | 0.65 | 0.05 | −0.21 | 0.30 | ||
| 200 - <400 | 0.75 | 0.13 | 1.37 | 0.25 | −0.11 | 0.60 | ||
| ≥400 | 0.02 | −0.39 | 0.43 | 0.08 | −0.15 | 0.32 | ||
| Dietary vitamin D, IU/day | 0.10 | 0.11 | ||||||
| <200 | 0.08 | −0.25 | 0.40 | 0.02 | −0.17 | 0.20 | ||
| ≥200 | 0.57 | 0.09 | 1.06 | 0.29 | 0.01 | 0.57 | ||
| Dietary sodium intake, mg/day | 0.46 | 0.98 | ||||||
| < 2040 | 0.02 | −0.52 | 0.56 | 0.10 | −0.21 | 0.42 | ||
| 2040 - < 2698 | 0.44 | −0.10 | 0.98 | 0.16 | −0.15 | 0.47 | ||
| 2698 - < 3521 | 0.00 | −0.54 | 0.54 | 0.08 | −0.23 | 0.39 | ||
| ≥ 3521 | 0.46 | −0.08 | 1.00 | 0.05 | −0.26 | 0.36 | ||
| 25 Hydroxyvitamin D level, nmol/liter# | 0.82 | 0.26 | ||||||
| < 34.4 | −0.29 | −2.64 | 2.05 | 0.28 | −1.02 | 1.57 | ||
| 34.4 - 47.6 | −1.57 | −3.89 | 0.74 | −1.43 | −2.71 | −0.16 | ||
| 47.7 - 64.6 | −0.22 | −2.56 | 2.12 | −0.04 | −1.33 | 1.25 | ||
| ≥ 64.7 | −1.10 | −3.43 | 1.23 | −0.14 | −1.42 | 1.14 | ||
| Diet modification trial assignment | 0.13 | 0.32 | ||||||
| Intervention | 0.58 | 0.07 | 1.10 | 0.30 | −0.00 | 0.59 | ||
| Comparison | −0.08 | −0.48 | 0.33 | 0.00 | −0.23 | 0.24 | ||
| Hormone therapy trial assignment | 0.16 | 0.05 | ||||||
| Estrogen + Progestin active | 1.07 | 0.34 | 1.80 | 0.34 | −0.07 | 0.76 | ||
| Estrogen + Progestin placebo | 0.14 | −0.60 | 0.88 | 0.44 | 0.02 | 0.86 | ||
| Estrogen-alone active | −0.66 | −1.60 | 0.28 | −0.21 | −0.75 | 0.32 | ||
| Estrogen-alone placebo | 0.33 | −0.61 | 1.26 | 0.32 | −0.21 | 0.86 | ||
Abbreviations: BMI, body mass index (weight in kilograms divided by the square of height
Positive mean differences between treatment groups indicate that BP was lowered less in the Calcium/Vitamin D group than in the placebo group during follow-up.
Test of interaction between Calcium/Vitamin D assignment and variable of interest, based on linear repeated measures model with unstructured correlation matrix.
Test of main effect of Calcium/Vitamin D assignment, based on linear repeated measures model with unstructured correlation matrix.
At randomization into the Calcium/Vitamin D trial.
Includes women who self-reported treatment for hypertension or who had at least one BP ≥ 140/90 mm Hg up to the time of Calcium/Vitamin D randomization.
From diet and supplements
Limited to Calcium/Vitamin D trial participants with available measurements, who were controls in nested case-control studies examining fractures, breast cancer, and colorectal cancer.