The Influence of Skin Pigmentation on UVB Induced Vitamin D Increase

NCT03409510 | Completed

• 1 other identifier: Dpigment2010
• Study Type: interventional
• Target: 43
• Locations: 1 country
• Sites: 1

Brief 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

Keywords

vitamin D; 25(OH)D; skin pigmentation; UVB; pigment genes

Outcome Measures

Primary Outcomes (1)

• Change in serum 25(OH)D

  Serum 25(OH)D is a marker of vitamin D increase induced by UVB

  Measured at study start and weekly over nine weeks

Study Arms (1)

Long-term UVB radiation

EXPERIMENTAL

All participants received repeated UVB radiation for nine weeks. The treatment was identical for all participants.

Radiation: UVB radiation

Interventions

UVB radiation 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

Long-term UVB radiation

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Fitzpatrick Skin type I-IV (light-skinned)
• Fitzpatrick Skin type V-VI (darker-skinned).

You may not qualify if:

• Vitamin D supplementation exceeding 10 µg/day one month prior to study start
• Vitamin D supplementation during study period
• Sun holiday south of latitude 45 degrees N one month prior to or during the study start
• Use of solarium one month prior to or during the study period
• Chronic disease
• Skin disease
• Intake of cholesterol-lowering or photosensitising medication
• Pregnancy
• Drug addiction
• Psychiatric disorder
• Physical disabilities.

Sponsors & Collaborators

• Bispebjerg Hospital: lead
• Rigshospitalet, Denmark: collaborator

Study Sites (1)

Department of Dermatology, D92, Bispebjerg Hospital

Copenhagen NV, 2400, Denmark

Location

MeSH Terms

Conditions

Pigmentation Disorders

Condition Hierarchy (Ancestors)

Skin Diseases; Skin and Connective Tissue Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Hans C Wulf, Professor

  Bispebjerg Hospital

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: MD

Model Details: This is single-centre, open and non-blinded clinical trial. Enrolled participants were allocated into two groups, light-skinned group and darker-skinned group, based on their Fitzpatrick Skin Type and ethnic origin. As both groups received identical intervention no masking was used. The main purpose was to include participants representing a broad variation in skin pigmentation for common analysis. To ensure this, participants were allocated into two groups and firstly analysed as such to determine if a common analysis was possible.

Study Record Dates

• First Submitted: January 10, 2018
• First Posted: January 24, 2018
• Study Start: November 1, 2010
• Primary Completion: January 22, 2011
• Study Completion: June 25, 2011
• Last Updated: January 31, 2018

Record last verified: 2018-01

Locations

DK (1)