Vitamin D Deficiency, Vitamin; Excess Vitamin D (Nutritional)
Conditions
Keywords
ODIN, Meta-analysis, Cholecalciferol, 25(OH)D, Subgroup effects
Brief summary
This meta-analysis will be conducted to study the effect on vitamin D supplements on markers for cardiovascular disease and diabetes using individual participant data from 12 RCTs. Given that previous data suggest that vitamin D supplementation might be most effective in those individuals with very low 25-hydroxyvitamin D (25(OH)D) and potentially harmful in those achieving very high levels after vitamin D supplementation, this meta-analyses will be performed in subgroups according 25(OH)D levels.
Detailed description
Large randomized controlled trials (RCTs) are currently on-going to evaluate non-skeletal effects of vitamin D supplementation in the general older population. The results of these studies can be expected in 2017 to 2020 and while they will report important data, they may still leave knowledge gaps on the effects of vitamin D on clinically relevant surrogate parameters in specific groups. Recent data indicate that the association of vitamin D status and outcome is U- or reverse J-shaped and may be modified by the presence of certain risk factors or genetic variations of the vitamin D receptor. This work is part of the European Union-project 'Food-based solutions for eradication of vitamin D deficiency and health promotion throughout the life cycle' (ODIN). This individual patient meta-analysis of existing high quality vitamin D RCTs aims to evaluate whether there are beneficial or harmful vitamin D effects on surrogate parameters for clinical outcomes (i.e. blood pressure, lipids, parathyroid hormone (PTH), fasting blood glucose and glycated haemoglobin (HbA1c)). With data from almost 3000 randomized subjects from 12 RCTs that are available within this consortium, the investigators will have sufficient power to detect clinically relevant effects of vitamin D supplementation on risk factors for cardiovascular disease. Subgroup analyses will investigate effect modifiers to evaluate whether certain groups of individuals experience pronounced or attenuated effects from vitamin D supplementation. Given that previous data suggest that vitamin D supplementation might be most effective in those individuals with very low 25(OH)D and potentially harmful in those achieving very high levels after vitamin D supplementation, this individual patient data meta-analyses will be performed in subgroups with serum 25(OH)D levels \<30, 40, and 50 nmol/L and \>100, 125 and 150 nmol/L. 25(OH)D levels will be re-measured to ensure comparability.
Interventions
None listed
Sponsors
European Union
Amsterdam UMC, location VUmc
Study design
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Availability of quality bio-banked samples for uniform 25(OH)D re-measurement * Prospective data on one or more of the outcomes * Willingness to collaborate
Exclusion criteria
* Trials among pregnant women, children, or performed in patient populations.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Blood pressure | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | Systolic and diastolic (Main outcome of cardiovascular markers) |
| HbA1c | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | (Main outcome of diabetic markers) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Total cholesterol | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | — |
| Triglycerides | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | — |
| Parathyroid hormone (PTH) | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | Parathyroid hormone |
| High-density lipoproteins (HDL) cholesterol | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | — |
| Fasting insulin | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | — |
| C-peptide | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | — |
| Two-hour glucose | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | After oral glucose tolerance test |
| Fasting glucose | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | — |
| Low-density lipoproteins (LDL) cholesterol | Participants were followed for the duration of the intervention period (range 8 weeks - 1 year, depending on the RCT in which they are participating) | — |
Outcome results
None listed