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Completed

NCT Number: NCT03818594

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

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 .

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Key information

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Nutrition Institute, Ljubljana

Ljubljana, 1000, Slovenia

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Primary outcomes

  1. Difference between vitamin D serum levels in winter and in summer season will be determined

    Time frame: 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 outcomes

  1. Correlation of vitamin D serum levels with Fitzpatrick skin phototype

    Time frame: 2 years

    Fitzpatrick skin phototype will be determined using Fitzpatrick self-evaluation questionnaire in combination with expert assessment in August-September.

  2. Correlation of vitamin D serum levels with skin colour measured in CIE Lab colour space

    Time frame: 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.

  3. Correlation of vitamin D serum levels with melanin index

    Time frame: 2 years

    Melanin index will be measured on inner and outer side of the upper arm. The measurement will be performed in August-September.

Sponsors and collaborators

Lead sponsor

Institute of Nutrition, Slovenia (Nutris)

Other

Collaborators

  • Slovenian Research Agency
  • VIST - Faculty of Applied Sciences
  • Valens Int. d.o.o., Slovenija

Registry information

Acronym: VITAD/1

Important dates

Study start
2019
Primary completion
2020
Study completion
2020
First posted
Jan 28, 2019
Registry last updated
Jun 18, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.