Vitamin D status and cardiometabolic risk markers in young Swedish children: a double-blind randomized clinical trial comparing different doses of vitamin D supplements

Abstract

Background: Observational studies have linked low vitamin D status to unfavorable cardiometabolic risk markers, but double-blinded vitamin D intervention studies in children are scarce.

Objectives: The aim was to evaluate the effect of different doses of a vitamin D supplement on cardiometabolic risk markers in young healthy Swedish children with fair and dark skin.

Methods: Cardiometabolic risk markers were analyzed as secondary outcomes of a double-blind, randomized, milk-based vitamin D intervention trial conducted during late fall and winter in 2 areas of Sweden (latitude 63°N and 55°N, respectively) in both fair- and dark-skinned 5- to 7-y-old children. During the 3-mo intervention, 206 children were randomly assigned to a daily milk-based vitamin D3 supplement of either 10 or 25 µg or placebo (2 µg; only at 55°N). Anthropometric measures, blood pressure, serum 25-hydroxyvitamin D [25(OH)D], total cholesterol, HDL cholesterol, apoA-I, apoB, and C-reactive protein (CRP) were analyzed and non-HDL cholesterol calculated at baseline and after the intervention.

Results: At baseline, serum 25(OH)D was negatively associated with systolic and diastolic blood pressure (β = -0.194; 95% CI: -0.153, -0.013; and β = -0.187; 95% CI: -0.150, -0.011, respectively). At follow-up, there was no statistically significant difference in any of the cardiometabolic markers between groups.

Conclusions: We could not confirm any effect of vitamin D supplementation on serum lipids, blood pressure, or CRP in healthy 5- to 7-y-old children. The study was registered at clinicaltrials.gov (NCT01741324).

Keywords: blood pressure; latitude; serum lipids; skin color; vitamin D supplement.

Copyright © The Author(s) 2020.

Figures

FIGURE 1

Flow diagram of Swedish 5- to 7-y-old study children, randomly assigned to milk-based vitamin D3 supplements [10 or 25 µg or placebo (2 µg)] during 3 winter months, followed from baseline until analysis.

FIGURE 2

Profile plot of observed mean values of cardiometabolic markers at baseline and follow-up for placebo (n = 35), the 10-µg group (n = 70), and the 25-µg group (n = 84), with corresponding 95% CIs. Note that the randomization solely by chance resulted in spurious group differences that may appear as dose–response relations already at baseline for TC, non–HDL cholesterol, HDL cholesterol, apoA-I, and apoB. hsCRP, high-sensitivity C-reactive protein; TC, total cholesterol.