A randomized controlled trial found that vitamin D3 supplementation combined with calcium may be associated with significant reductions in both systolic and diastolic blood pressures among overweight elderly patients over a 12-month period.
In the multicenter, double-blind study, published in the Journal of the Endocrine Society, researchers enrolled 257 participants aged 65 or older with a body mass index (BMI) of over 25 and serum 25-hydroxyvitamin D levels of 10 to 30 ng/mL. After excluding dropouts and 1 participant without baseline vitamin D data, 221 ambulatory adults completed the trial (111 on low-dose and 110 on high-dose vitamin D3 supplementation).
The study population had notable comorbidities: 69% had prediabetes, 65% were hypertensive, and 64% had dyslipidemia. At baseline, 48% of the participants were receiving antihypertensive medications and 34% had a blood pressure or 130/80 mmHg ore more without treatment.
The trial included regular compliance checks, with participants attending visits every 3 months and receiving biweekly phone calls. Blood pressure measurements were taken after 5 minutes of rest, with repeated readings for elevated measurements. All participants also received 1,000 mg of calcium citrate daily.
The participants in the high-dose vitamin D3 group (3,750 IU/day) experienced mean systolic reductions of 4.2 mmHg and diastolic reductions of 3.02 mmHg after 1 year. Those receiving low-dose vitamin D3 supplementation (600 IU/day) showed nonsignificant reductions in systolic (2.8 mmHg) and diastolic (2.6 mmHg) pressures.
In the patients with a BMI over 30 (n = 99), significant systolic blood pressure decreases were observed in both dosage groups (high-dose: from 132.9 to 125.8 mmHg; low-dose: from 132 to 124.5 mmHg). Diastolic pressure decreased significantly in the high-dose group (from 77.3 to 73.3 mmHg).
Among participants with hypertension (n = 143), defined as having a systolic pressure of 130 mmHg or more or a diastolic pressure of 80 mmHg or more at study entry, significant reductions were observed regardless of vitamin D dosage or BMI category. In this group, systolic pressure decreased from 136.5 to 126.5 mmHg and diastolic from 79.8 8.2 to 72.8 mmHg.
The study excluded patients with diabetes, severe chronic diseases, major organ failure, or conditions affecting bone metabolism. Only nine of the participants reported regular physical activity, limiting analysis of lifestyle effects on blood pressure outcomes.
The researchers acknowledged several limitations of the study, including the exploratory nature of their analyses and the absence of a placebo-only control group. The study population was primarily sedentary, overweight, and included many with prediabetes, which may limit generalizability to other populations.
The trial was conducted at the American University of Beirut Medical Center, St. Joseph University Hospital, and Rafic Hariri Governmental University Hospital, with support from several institutional and NIH grants.
All authors stated that they have no conflict of interest.