Getting vitamin D dosing right
Research type
Research Study
Full title
Determining the effects of race, skin colour and genotype on the response to vitamin D therapy
IRAS ID
147181
Contact name
Jaya Sujatha Gopal Kothandapani
Contact email
Sponsor organisation
Sheffield Children's NHS Foundation Trust
Research summary
The Department of Health and the Chief Medical Officer have identified vitamin D deficiency as a key area of interest and concern for public health. The main function of vitamin D is to enable dietary calcium to be absorbed from the intestine. Low levels of vitamin D can lead to diseases of bone such as rickets and osteomalacia and are linked to a higher risk of fracturing bones in older women with osteoporosis.Vitamin D levels may be affected by the skin colour, body mass index (BMI), lifestyle or environment in which someone lives, and by their genetic make-up. Vitamin D levels tend to be lower in people with higher BMI and / or darker coloured skin or if the skin is covered by clothing because a lot of vitamin D is made from the action of sunlight on natural chemicals in the skin.Vitamin D does occur naturally in the diet in foods like oily fish, and also vitamin D can be given as a supplement either on its own or as part of a multivitamin tablet. There is natural variation from one person to another in how well the system controlling vitamin D blood levels works. Vitamin D circulates bound to a carrier protein, vitamin D binding protein (VDBP). When vitamin D levels are measured, both vitamin D bound to the protein and “free” vitamin D are measured. A recent study in America showed that when “free” vitamin D levels (total vitamin D minus vitamin D bound to VDBP) are measured, they correlate very closely with other factors that help determine blood calcium levels.This variation is determined in part by a person’s genetic makeup, and recent large studies have identified specific genetic variations that are linked to blood levels of vitamin D; some of these vary with the person’s ethnic origin.At present if someone has low vitamin D levels that put them at increased risk of bone problems, a course of vitamin D treatment is given. When we assessed our regular treatment given to children recently, we found some individuals developed very high blood vitamin D levels and others didn’t. We don’t know how VDBP levels affect the response to treatment with vitamin D.Further variation can occur because of the distribution of vitamin D into fat tissue. We will measure height and weight, and waist and hip circumference and calculate Body Mass Index, body surface area (BSA) and waist: hip ratio as proxy measures of fat mass.We want to make sure that people get the right dose of treatment. We will therefore investigate how skin colour,BMI,ethnicity,VDBP and genetic variation affect the response to a standard course of vitamin D in young adults, as a prelude to further studies in younger children.
REC name
Yorkshire & The Humber - Leeds West Research Ethics Committee
REC reference
14/YH/1149
Date of REC Opinion
21 Oct 2014
REC opinion
Further Information Favourable Opinion