Challenges in Achieving Adequate Vitamin D Status in the Adult Population - Part 1

Completed

• Conditions: Vitamin D Serum Levels

• Registration Number: NCT03818594
• Lead Sponsor: Nutrition Institute, Slovenia

Brief Summary

Seasonal variations in vitamin D status will be determined on a cohort of Slovenian adults using longitudinal study design, and association between vitamin D status and different Caucasian phototypes, skin colour and melanin index investigated .

Detailed Description

Not available

Study Timeline

• Study Start: 2019-01-08
• Study First Submitted: 2019-01-17
• Study First Submitted QC: 2019-01-25
• Study First Posted: 2019-01-28
• Primary Completion: 2020-09-28
• Study Completion: 2020-09-28
• Status Verified: 2021-06
• Last Update Submitted: 2021-06-16
• Last Update Posted: 2021-06-18

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 338

Inclusion Criteria

• Signed Informed consent form (ICF),
• Caucasian race
• Age between 18 and 65 years at the time of the signature of Informed consent form (ICF),
• Willingness to avoid a consumption of any food supplements containing Vitamin D during the study, except the ones prescribed by the study researchers, and to avoid use of solarium or other artificial UVB sources
• Willingness to follow all study procedures

Exclusion Criteria

• Pregnancy or breastfeeding,
• Known or suspected allergy to any ingredient of the tested products in Part 2,
• Pronounced avoidance of sunshine (eg reporting of allergy to the sun)
• Use of food supplements containing Vitamin D or fish oil or omega 3 fatty acids in last three months prior to inclusion,
• Special dietary habits used by a small part of the population (veganism, low-carb hihg-fat diet, caloric restriction diet, note: vegetarians are not excluded)
• Diets prescribed by the medical profession
• Disorders of the kidneys, thyroid, digestive tract, osteoporosis and other bone diseases, skin diseases
• Other diseases and conditions that affect the absorption and synthesis of vitamin D
• Exposure to stronger sunlight in the last three months prior to engaging in a survey (travel to countries with stronger sunshine, use of solarium),
• The consumption of margarine or plant substitutes for milk / milk products several times a day, as these foods are most often enriched with vitamin D,
• Visiting the solarium in the last three months before joining the survey,
• Mental incapacity that precludes adequate understanding or cooperation.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Difference between vitamin D serum levels in winter and in summer season will be determined	2 years	Vitamin D serum level will be measured once in winter (December - January) and once in summer season (August-September) for each individual. The study will be performed over two consecutive years.

Secondary Outcome Measures

Name	Time	Method
Correlation of vitamin D serum levels with melanin index	2 years	Melanin index will be measured on inner and outer side of the upper arm. The measurement will be performed in August-September.
Correlation of vitamin D serum levels with Fitzpatrick skin phototype	2 years	Fitzpatrick skin phototype will be determined using Fitzpatrick self-evaluation questionnaire in combination with expert assessment in August-September.
Correlation of vitamin D serum levels with skin colour measured in CIE Lab colour space	2 years	Skin colour will be measured in CIE Lab colour space on inner and outer side of the upper arm. The measurement will be performed in August-September.

Trial Locations

Locations (1)

Nutrition Institute, Ljubljana; 🇸🇮 Ljubljana, Slovenia