OASIS Study: Vitamin D Deficiency Prevention Among Older Adults in Ireland

NCT06705582 | Completed

• 1 other identifier: OASIS
• Study Type: interventional
• Target: 117
• Locations: 1 country
• Sites: 2

Brief Summary

Vitamin D deficiency is common. It is caused by limited sun availability together with a low supply of vitamin D in the food system. There is a high prevalence of low vitamin D status around the world. In Ireland, our relatively northern latitude and prevailing weather mean that UVB availability for skin synthesis of vitamin D is limited in this country and our population relies on the dietary supply of vitamin D to prevent deficiency. Thus, the endemic Irish problem of vitamin D malnutrition is due to the lack of vitamin D in our food system. Dietary guidelines cannot address this issue because foods naturally rich in vitamin D are very few and infrequently consumed. The OASIS study will test the hypothesis that a vitamin D-fortified bread as part of a healthy diet that includes vitamin D-fortified foods is effective in preventing low vitamin D status during winter, and safe for older adults to consume.

Conditions

Vitamin D Deficiency

Outcome Measures

Primary Outcomes (1)

• Serum concentrations of 25-hydroxyvitamin D (25(OH)D)

  Comparison of the number of participants with low vitamin D status (e.g. \<30 nmol/L and \< 50 nmol/L serum 25(OH)D) between treatment and placebo groups

  10 weeks

Secondary Outcomes (3)

• Vitamin D intakes

  10 weeks

• Serum concentrations of albumin-corrected serum calcium concentrations as a safety measure

  10 weeks

• Circulating biomarkers of metabolic health status

  10 weeks

Study Arms (2)

Fortified bread

EXPERIMENTAL

Intervention group will be supplied with fortified bread

Other: Fortified Bread

Unfortified bread

PLACEBO COMPARATOR

Control arm will receive unfortified bread and dietary advice to incorporate fortified foods that are commonly available on the market in their diet.

Other: Unfortified bread

Interventions

Fortified Bread OTHER

Intervention group will be supplied with fortified bread delivering 10 -15 μg (400-600 IU) vitamin D3 in a daily portion and will receive dietary advice to incorporate fortified foods that are commonly available on the market in their diet.

Fortified bread

Unfortified bread OTHER

Placebo control group will be supplied with unfortified bread and will receive dietary advice to incorporate fortified foods that are commonly available on the market in their diet.

Unfortified bread

Eligibility Criteria

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

You may qualify if:

• Provide written informed consent.
• Be an adult ≥65 years.
• Willing to consume bread provided and have storage capacity for frozen bread.
• Be in good general health.
• Be willing to follow the assigned diet for 10 weeks and attend the required appointments.

You may not qualify if:

• Regularly consume a single high dose vitamin D supplement (\>10µg/d /400 IU equivalent).
• \. Exposure to factors that may influence vitamin D status, such as winter sun holiday, tanning bed usage.
• \. Are following a medically prescribed diet. 4. Have a diagnosis of an acute or chronic medical condition that in the opinion of the investigator would interfere with the outcomes of the study such as Coeliac disease, Inflammatory Bowel Disease, liver disease, renal disease, pancreatic disease or gastric disease.
• \. Have a history of active cancer or a diagnosis of cancer within the past 5 years.
• \. Are taking certain medications that can impact vitamin D status, such as glucocorticoids.
• \. Have regular excessive alcohol intake (≥28 units per week). 9. Have a known food allergy. 10. Are participating in another research study with an intervention or other lifestyle programme that would interfere with the outcomes of the study.
• \. Are unable to read, write, or understand English.

Sponsors & Collaborators

• University College Cork: lead
• University College Dublin: collaborator

Study Sites (2)

Human Nutrition Studies Unit, School of Food and Nutritional Sciences

Cork, Cork, T12 K8AF, Ireland

Location

UCD Institute of Food and Health

Dublin, Dublin, D04 N2E5, Ireland

Location

MeSH Terms

Conditions

Vitamin D Deficiency

Condition Hierarchy (Ancestors)

Avitaminosis; Deficiency Diseases; Malnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases

Study Officials

• Mairead E Kiely, PhD

  University College Cork

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: November 15, 2024
• First Posted: November 26, 2024
• Study Start: November 11, 2024
• Primary Completion: March 31, 2025
• Study Completion: March 31, 2025
• Last Updated: April 30, 2025

Record last verified: 2025-04

Data Sharing

• IPD Sharing: Will not share

Locations

IE (2)