NCT03318029: D-SOL

Vitamin D Supplementation and Sunlight Exposure in Brazilian Women Living in Opposite Latitudes (The D-SOL Study)

Completed NA Last updated 23 October 2017

What this trial tests

NA trial testing Vitamin D supplementation in Vitamin D Deficiency in 136 participants. Completed in 25 September 2017.

Timeline

1 October 2016

Primary endpoint
25 September 2017

25 September 2017

Quick facts

Lead sponsor	University of Surrey
Phase	NA
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	double
Primary purpose	prevention
Enrollment	136
Start date	1 October 2016
Primary completion	25 September 2017
Estimated completion	25 September 2017
Sites	2 locations across United Kingdom, Brazil

Drugs / interventions tested

• Vitamin D supplementation
• Placebo

Conditions studied

• Vitamin D Deficiency — all drugs for Vitamin D Deficiency →

Sponsor

University of Surrey

Who can join

Adults 20 to 59, female only, with Vitamin D Deficiency. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

There is a consensus that vitamin D deficiency is a public health issue because of its implications in several diseases including, osteopenia, osteomalacia, heart disease, diabetes (type I and II), inflammatory diseases, multiple sclerosis and rheumatoid arthritis. Studies in sunny countries have shown that vitamin D deficiency is a common phenomenon, despite the abundance of sunlight in these places, which shows the influence of diet, skin pigmentation, cultural habits and also genetic factors on the metabolism of this vitamin. Thus, the study hypothesis is that vitamin D supplementation is required to obtain the optimal serum concentration in Brazilian people living both in Brazil and in the United Kingdom and that this response is dependent on the initial levels, being influenced by sunlight exposure, skin pigmentation, diet and polymorphisms of the vitamin D receptor gene. Two controlled, randomized, double-blind clinical trials were held (one in the UK and the other in Brazil) over a period of 12 weeks, with female subjects, Brazilian, aged 20 to 59 years. The women selected were divided into two groups: Placebo Group and Supplemented Group, the latter received vitamin D 600 IU. After the analysis of the effect of vitamin D supplementation compared to placebo, the investigators propose to analyse genome-wide transcriptomic expression in order to associate specific signal transduction and metabolic pathways to respective vitamin D responses. and a genetic risk score based on polymorphisms will be constructed. The 'systems level' approach will enable us to identify differences in gene expression and whether this explains why some individuals are 'good' responders or 'poor' responders to vitamin D supplementation. This is the first study that will examine two population groups of the same ethnic group and sex, living in different countries, with identical design studies. Our results first will determine how important supplementation and exposure to sunlight are for the serum level of vitamin D by comparing directly, using the same methodology, people living in different latitudes, as well as the genetic influence on the response to supplementation. The data will also provide both countries key data about the need to reconsider new revisions to dietary recommendations for vitamin D in adults.

Publications & conference data

5 peer-reviewed publications reference this trial (live from Europe PMC):

1. Nuclear receptors in health and disease: signaling pathways, biological functions and pharmaceutical interventions.
   Jin P, Duan X, Huang Z, Dong Y, et al · · 2025 · cited 21× · PMID 40717128 · DOI 10.1038/s41392-025-02270-3
2. Association between 25-Hydroxyvitamin D, Parathyroid Hormone, Vitamin D and Calcium Intake, and Bone Density in Healthy Adult Women: A Cross-Sectional Analysis from the D-SOL Study.
   Mendes MM, Hart KH, Lanham-New SA, Botelho PB. · · 2019 · cited 19× · PMID 31167443 · DOI 10.3390/nu11061267
3. Suppression of Parathyroid Hormone as a Proxy for Optimal Vitamin D Status: Further Analysis of Two Parallel Studies in Opposite Latitudes.
   Mendes MM, Hart KH, Lanham-New SA, Botelho PB. · · 2020 · cited 16× · PMID 32231092 · DOI 10.3390/nu12040942
4. Exploring the Impact of Individual UVB Radiation Levels on Serum 25-Hydroxyvitamin D in Women Living in High Versus Low Latitudes: A Cross-Sectional Analysis from the D-SOL Study.
   Mendes MM, Hart KH, Lanham-New SA, Botelho PB. · · 2020 · cited 15× · PMID 33322498 · DOI 10.3390/nu12123805
5. Vitamin D Supplementation and Sunlight Exposure on Serum Vitamin D Concentrations in 2 Parallel, Double-Blind, Randomized, Placebo-Controlled Trials.
   Mendes MM, Hart KH, Williams EL, Mendis J, et al · · 2021 · cited 12× · PMID 34255034 · DOI 10.1093/jn/nxab209