Clinical trial NCT03818594: Challenges in Achieving Adequate Vitamin D Status in the Adult Population - Part 1
Official title: Challenges in Achieving Adequate Vitamin D Status in the Adult Population - Part 1
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Vitamin D Serum Levels
Lead sponsor: Nutrition Institute, Slovenia
Sponsor class: OTHER
Collaborators: name: VIST - Faculty of Applied Sciences
name: Slovenian Research Agency
name: Valens Int. d.o.o., Slovenija
First posted: 2019-01-28
Enrollment: 338
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: General Slovenian adult population, men and women, skin phototypes I-IV.

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 .


Eligibility criteria: 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.

Primary outcomes:
measure: Difference between vitamin D serum levels in winter and in summer season will be determined
timeFrame: 2 years
Secondary outcomes:
measure: Correlation of vitamin D serum levels with Fitzpatrick skin phototype
timeFrame: 2 years
measure: Correlation of vitamin D serum levels with skin colour measured in CIE Lab colour space
timeFrame: 2 years
measure: Correlation of vitamin D serum levels with melanin index
timeFrame: 2 years
Other outcomes:
Locations:
city: Ljubljana
country: Slovenia
facility: Nutrition Institute, Ljubljana
Study officials:
affiliation: Researcher
name: Katja Žmitek, PhD
role: PRINCIPAL_INVESTIGATOR
References: