Inflammation, Malaria, Vitamin A Deficiency
Conditions
Keywords
Vitamin A status, Retinol Isotope Dilution, Nigeria, Preschool children, Malaria, Inflammation
Brief summary
For assessing body retinol pools in preschool children, it is recommended that a blood sample is taken 14-21 days after isotope dosing. During this period, dietary intake of vitamin A should be controlled. Shortening of this period as has been validated for adults would reduce the burden for the children as well as improve research efficiency. The aim is to validate a 4-day protocol for assessing body retinol pools in preschool children by modelling data derived by retinol isotope dilution (RID) method. Venous blood samples will be collected of 60 children 4 days after dosing of 0.4 mg 13C-labeled retinyl acetate. A second venous blood sample will be collected at 6, 8, 12 hrs; and 1, 2, 4, 7, 11, 16, 22 and 28 days after dosing in subgroups of 6 children, randomly divided over the 10 additional time points. Body retinol pools will be modelled, and the time point at which a parsimonious model applies (presumably at day 4) will be assessed.
Detailed description
For assessing body retinol pools in preschool children, it is recommended that a blood sample is taken 14-21 days after isotope dosing. During this period, dietary intake of vitamin A should be controlled. Shortening of this period as has been validated for adults would reduce the burden for the children as well as improve research efficiency. The aim is to validate a 4-day protocol for assessing body retinol pools in preschool children by modelling data derived by retinol isotope dilution (RID) method. A secondary aim is to compare body retinol pools between children with and without inflammation and to assess the effect of asymptomatic malaria on model parameters. Preschool children (n=60), 36-59 months of age, residing in Telemu, Osun State, Nigeria will be recruited for the study. The study design is an observational pre/post study, for which body retinol pools will be measured using the RID method. Venous blood samples will be collected of all children 4 days after dosing of 0.4 mg 13C-labeled retinyl acetate. A second venous blood sample will be collected at 6, 8, 12 hrs; and 1, 2, 4, 7, 11, 16, 22 and 28 days after dosing in subgroups of 6 children, randomly divided over the 10 additional time points. Children presenting with asymptomatic malaria will be treated, and a convenience subsample (n=10) will undergo a second assessment of body retinol pools determined with a venous blood collection on day 4 post-dosing only. Body retinol pools will be modelled, and the time point at which a parsimonious model applies (presumably at day 4) will be assessed. Presence of asymptomatic malaria and markers of inflammation will be assessed in all children at all time points. Body retinol pools and model parameters between subgroups of children with and without asymptomatic malaria and/or inflammation will be compared. Pre/post comparisons of body retinol pool estimates will be done for the follow up subsample.
Interventions
OTHERRetinol Isotope Dilution (RID)
13C-retinyl acetate will be administered to subjects in order to assess their body retinol pools
Sponsors
University of Ibadan
Newcastle University
University of California, Davis
Penn State University
HarvestPlus
Wageningen University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
36 Months to 59 Months
Healthy volunteers
Yes
Inclusion criteria
* Apparently healthy * Between 36 and 59 months of age * Living in the community of Telemu, Osun State, Nigeria, or its neighbouring communities
Exclusion criteria
* Active or recent disease with a potential effect on study outcome * Hb concentration \<70 g/dL * Mental state that is incompatible with participation in the study * Recent exposure to 13C-retinol stable isotopes * Unwillingness to participate by verbal or physical expression
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Vitamin A status | 28 days | Body retinol pool |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Serum retinol | 28 days | Serum concentration of retinol (HPLC) |
| Ferritin concentration | 28 days | Serum concentration of ferritin (ELISA) |
| Soluble transferrin receptor concentration | 28 days | Serum concentration of soluble transferrin receptor concentration (ELISA) |
| Retinol binding protein | 28 days | Serum concentration of retinol binding protein (ELISA) |
| Prevalence of malaria (plasmodium falciparum) | 28 days | Percentage of children with malaria (Plasmodium falciparum) as determined by a rapid test (CareStart Malaria HRP2) and confirmed by PCR. |
| Prevalence of inflammation | 28 days | Percentage of children with C-reactive protein (CRP) \>5 mg/L and/or alpha-glycoprotein (AGP) \>1 g/L |
| Blood haemoglobin concentration | 28 days | Haemoglobin concentration (Quikread) |
Other
| Measure | Time frame | Description |
|---|---|---|
| Body length | Baseline | Body length will be measured to the nearest 1 cm with a stadiometer |
| Body weight | Baseline | Body weight will be measured to the nearest 0.1 kg with a weighing scale |
| Dietary intake of energy, protein, fat, carbohydrates, vitamins and minerals | Baseline | Group mean intake of macronutrients and micronutrients, assessed by 24h recall |
Countries
Nigeria
Outcome results
None listed