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The Influence of Skin Pigmentation on UVB Induced Vitamin D Increase

NCT03409510 · Status: COMPLETED · Phase: NA · Type: INTERVENTIONAL · Enrollment: 43

Last updated 2018-01-31

No results posted yet for this study

Summary

Skin pigmentation (melanin) absorbs ultra violet type B (UVB) radiation found in sunlight and is believed to be responsible for darker-skinned persons' generally low 25(OH)D status. This phenomenon is found in immigrants living in Northern countries and their 25(OH)D responses to UVB-irradiation seem low.

We hypothesized that objectively measured skin pigmentation and/or pigment genes influence UVB-induced 25(OH)D increase significantly in combination with other influential parameters.

The influence of objectively measured constitutive and facultative skin pigmentation on UVB-induced 25(OH)D increase over time was investigated together with other possible influential parameters. These other influential parameters include sex, age, weight, height, BMI, number of fatty fish meals per week, Fitzpatrick Skin Type and 25(OH)D start level. The genetic parameters include 33 Vitamin D receptor and pigment SNPs.

This is a single-centre, open and non-blinded clinical trial. No randomisation was used, as the participants were allocated into two groups based on their Fitzpatrick Skin type and ethnic origin. The light-skinned group included participants with Fitzpatrick Skin type II-IV and were of Northern origin (Denmark, the Faroe Islands and the UK). The darker-skinned included Fitzpatrick Skin Types V-VI originating from countries located at latitudes below 50 degrees N. Thus, it could be ensured that the participants represented a wide range of skin pigmentation. The light-skinned (N = 22) and the darker-skinned subjects (N = 18) were exposed to identical UVB doses on identical body areas over nine weeks with weekly measurements of 25(OH)D. The UVB-induced 25(OH)D synthesis was investigated in summer-pigmented skin with melanin throughout the epidermis and during winter when ambient UVB exposure is negligible. Demographic data (gender, age, weight, height, Fitzpatrick Skin Type, measured constitutive and facultative skin pigmentation (PPF)) was collected/measured and registered in prior to study start. The number of daily consumed fatty fish meals was recorded in a questionnaire. Serum 25(OH)D was analysed weekly.

Conditions

  • Healthy Volunteers

Interventions

RADIATION

UVB radiation

UVB treatment regimen: Week 1-2: 0.85 kilo Joule/m2 twice per week Week 3-7: 0.85 kilo Joule/m2 three times per week Week 8-9: 1.4 kilo Joule/m2 three times per week

Sponsors & Collaborators

  • Rigshospitalet, Denmark

    collaborator OTHER

  • Bispebjerg Hospital

    lead OTHER

Principal Investigators

  • Hans C Wulf, Professor · Bispebjerg Hospital

Study Design

Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2010-11-01
Primary Completion
2011-01-22
Completion
2011-06-25

Countries

  • Denmark

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT03409510 on ClinicalTrials.gov