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

Summary

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.

Conditions

• Vitamin D Deficiency

Interventions

DIETARY_SUPPLEMENT

Vitamin D supplementation

Vitamin D supplementation of 600 IU daily for 12 weeks

DIETARY_SUPPLEMENT

Placebo

rice flour with no vitamin D

Sponsors & Collaborators

• Conselho Nacional de Desenvolvimento Científico e Tecnológico

  collaborator OTHER_GOV

• Universidade Federal de Goiás

  collaborator UNKNOWN

• University of Surrey

  lead OTHER

Principal Investigators

• Kath Hart, Ph.D · Lecturer, Department of Nutritional Sciences, University of Surrey

• Patricia Borges Botelho, Ph.D · Lecturer, Post-graduate Department of Nutrition, Federal University of Goiás

• Laura Tripkovic, Ph.D · Teaching Fellow, Department of Nutritional Sciences, University of Surrey

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

20 Years

Max Age

59 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2016-10-01

Primary Completion

2017-09-25

Completion

2017-09-25

Countries

• Brazil
• United Kingdom

Study Locations