<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT04438200</url>
  </required_header>
  <id_info>
    <org_study_id>VDACS-MF-0109-2019</org_study_id>
    <nct_id>NCT04438200</nct_id>
  </id_info>
  <brief_title>Liver and Bone Retinol Levels in Guatemalan Adolescents and Adults</brief_title>
  <acronym>GVAS</acronym>
  <official_title>Niveles de Retinol Hepatico y óseo en cadáveres de Adolescentes y Adultos Guatemaltecos (Liver and Bone Retinol Levels in Guatemalan Adolescents and Adults)</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>Newcastle University</agency>
      <agency_class>Other</agency_class>
    </lead_sponsor>
    <collaborator>
      <agency>Bill and Melinda Gates Foundation</agency>
      <agency_class>Other</agency_class>
    </collaborator>
    <collaborator>
      <agency>HarvestPlus</agency>
      <agency_class>Other</agency_class>
    </collaborator>
    <collaborator>
      <agency>Institute of Nutrition of Central America and Panama</agency>
      <agency_class>Other</agency_class>
    </collaborator>
    <collaborator>
      <agency>INACIF</agency>
      <agency_class>Other</agency_class>
    </collaborator>
  </sponsors>
  <source>Newcastle University</source>
  <oversight_info>
    <has_dmc>No</has_dmc>
    <is_fda_regulated_drug>No</is_fda_regulated_drug>
    <is_fda_regulated_device>No</is_fda_regulated_device>
  </oversight_info>
  <brief_summary>
    <textblock>
      Guatemala has enforced mandatory fortification of sugar with vitamin A (VA) since June 1974&#xD;
      and has led to a highly successful reduction in VA deficiency and associated disease.&#xD;
      However, Ribaya-Mercado et al. 2014, estimated the biological impact of sugar fortified with&#xD;
      retinyl palmitate that there may be a risk of chronic excess intake of preformed VA&#xD;
      associated with programs of mass fortification. A recent food consumption survey in two&#xD;
      departments in Guatemala found the average daily sugar intake in children under the age of&#xD;
      two who aren´t being breastfed is 30.3 g, which translates into a daily intake of 272 μg of&#xD;
      retinol (almost the full estimated average requirement (EAR) for that age group). Since data&#xD;
      from the second National Survey on Micronutrients suggest a risk of VA toxicity, it is&#xD;
      important to determine the levels of hepatic VA directly in corpses of individuals, of all&#xD;
      ages, who have died of non-metabolic causes. Due to this, the investigators propose to assess&#xD;
      liver and bone VA levels in combination with gene expression, histopathology and biochemical&#xD;
      analyses, to elicit indications of hypervitaminosis A in Guatemala.&#xD;
    </textblock>
  </brief_summary>
  <detailed_description>
    <textblock>
      Objectives:&#xD;
&#xD;
        1. To determine the post mortem concentration of hepatic and bone VA in corpses of&#xD;
           adolescent, young and elderly adults as an indicator of exposure to dietary VA&#xD;
&#xD;
        2. To assess the effect of high VA exposure on key enzymes in liver and bone tissue and to&#xD;
           assess the risk of hypervitaminosis A in people exposed to compulsory mass vitamin A&#xD;
           fortification program in Guatemala.&#xD;
&#xD;
      Methodology:&#xD;
&#xD;
      Setting and sampling The corpses for this study will be obtained from the National Institute&#xD;
      of Forensic Sciences' (INACIF) departmental morgues in 2 hospitals in Guatemala City. The&#xD;
      study population will be 150 cadavers sampled for VA tissue concentration; gene expression&#xD;
      analysis combined with histopathology.&#xD;
&#xD;
      Sample collection process and duration All samples will be collected during necropsies&#xD;
      carried out at the INACIF forensic morgue. During necropsy, the liver will be weighed and the&#xD;
      information recorded. A range of up to 10 x 3 g samples of the liver's right lobe will be&#xD;
      obtained. Each sample will be properly labelled with previously prepared codes. Liver samples&#xD;
      for histopathological analysis will be stored in 10% buffered formalin for 24 hours prior to&#xD;
      transfer to ethanol before embedding, sectioning and staining. All samples collected for&#xD;
      retinoid analysis will be frozen on dry ice in the morgue, transported as such to the&#xD;
      laboratory and subsequently stored at -80˚C. Liver samples for gene expression analysis will&#xD;
      be collected in RNAlater solution to protect RNA stability and subsequently stored at -80˚C&#xD;
      until shipment to Newcastle University. The hepatic VA analysis will be done in Newcastle&#xD;
      University using established High Perfromance Liquid Chromatography (HPLC) methods. Samples&#xD;
      for analysis of gene expression will be sent on dry ice to Newcastle for RNA extraction and&#xD;
      quantification. Since it is possible to obtain good quality RNA suitable for Quantitative&#xD;
      Polymerase Chain Reaction (q-PCR) based analyses from post mortem tissue up to 72 hours after&#xD;
      death, tissue samples stored in RNAlater within 24 hours of death will be adequate for gene&#xD;
      expression analysis. Furthermore, experience from the investigators human biobank in&#xD;
      Newcastle shows that tissue RNA can be extracted successfully after the demise of a patient&#xD;
      up to 72 hours after death as long as the tissue has a pH of over 6. Gene expression of key&#xD;
      regulatory proteins, such as LRAT and CYP26A1 will be performed in Newcastle. Choice of genes&#xD;
      was based on the fact that LRAT may become saturated at very high levels of VA, leading to&#xD;
      increasing levels of free circulating VA that can be metabolized to retinoic acid and other&#xD;
      metabolites via CYP26A. Histopathological analysis will be carried out by pathologists in&#xD;
      Guatemala with digitised slides being sent to the pathologist within Newcastle University -&#xD;
      these slides will be analysed by both pathologists independently.&#xD;
&#xD;
      Bone samples will also be obtained during the necropsy carried out at the INACIF forensic&#xD;
      morgue. The iliac crest bone will be exposed by making an incision and removing the overlying&#xD;
      soft tissue (skin, adipose tissue, connective tissue and muscle). The periosteum and cortical&#xD;
      bone shall be removed via osteotomy exposing the spongy bone. Biopsy needles will be used to&#xD;
      take samples from the spongy bone for analysis of tissue VA concentrations and gene&#xD;
      expression, as previously described, at Newcastle University.&#xD;
&#xD;
      All samples will be shipped to Newcastle University on dry ice.&#xD;
&#xD;
      Study duration According to the information provided by INACIF 18 autopsies were performed&#xD;
      between March and May 2013 on children less than one year of age, 24 on children from 1 to 4&#xD;
      years old, 11 on children 5 to 9 years old, 51 on individuals from 10 to 14 years old, 281 on&#xD;
      adolescents 15 to 19 years old, and 401 on young adults 20 to 24 years old. According to&#xD;
      INACIF's forensic doctor, ~60% of the total number of autopsies carried out in Guatemala are&#xD;
      performed in the capital city. The main causes of death in children under the age of 9 were&#xD;
      head injuries and other types of trauma. Individuals from 10 to 24 years of age died mainly&#xD;
      due to violence: firearms, stabbings, choking and different types of trauma.&#xD;
    </textblock>
  </detailed_description>
  <overall_status>Unknown status</overall_status>
  <last_known_status>Recruiting</last_known_status>
  <start_date type="Actual">October 24, 2019</start_date>
  <completion_date type="Anticipated">July 2020</completion_date>
  <primary_completion_date type="Anticipated">July 2020</primary_completion_date>
  <study_type>Observational</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <observational_model>Other</observational_model>
    <time_perspective>Cross-Sectional</time_perspective>
  </study_design_info>
  <primary_outcome>
    <measure>Liver Vitamin A concentration</measure>
    <time_frame>Enrolment</time_frame>
    <description>Liver Vitamin A concentration</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Liver Gene Expression</measure>
    <time_frame>Enrolment</time_frame>
    <description>Gene expression associated with Vitamin A</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Liver Histology</measure>
    <time_frame>Enrolment</time_frame>
    <description>Histological changes associated with Vitamin A</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Bone Gene Expression</measure>
    <time_frame>Enrolment</time_frame>
    <description>Gene expression associated with Vitamin A</description>
  </primary_outcome>
  <secondary_outcome>
    <measure>Bone Vitamin A concentration</measure>
    <time_frame>Enrolment</time_frame>
    <description>Bone Vitamin A concentration</description>
  </secondary_outcome>
  <number_of_groups>3</number_of_groups>
  <enrollment type="Anticipated">150</enrollment>
  <condition>Vitamin A Deficiency</condition>
  <condition>Vitamin A Toxicity</condition>
  <condition>Hypervitaminosis A</condition>
  <arm_group>
    <arm_group_label>Adolescents</arm_group_label>
    <description>Individuals aged 10-19 years</description>
  </arm_group>
  <arm_group>
    <arm_group_label>Young Adults</arm_group_label>
    <description>Individuals aged 20-39 years</description>
  </arm_group>
  <arm_group>
    <arm_group_label>Elderly Adults</arm_group_label>
    <description>Individuals aged 40+ years</description>
  </arm_group>
  <biospec_retention>Samples With DNA</biospec_retention>
  <biospec_descr>
    <textblock>
      Liver Tissue Samples Bone Tissue Samples&#xD;
    </textblock>
  </biospec_descr>
  <eligibility>
    <study_pop>
      <textblock>
        Guatemalan cadavers, from 2 hospitals in Guatemala City, aged &gt;10 years with a&#xD;
        non-metabolic cause of death, within 24 hours of death&#xD;
      </textblock>
    </study_pop>
    <sampling_method>Non-Probability Sample</sampling_method>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
          -  Aged &gt;10 years&#xD;
&#xD;
          -  Non-metabolic cause of death (e.g. accidents, trauma, or violence from firearms,&#xD;
             stabbings, cranial and other trauma, asphyxiation etc.)&#xD;
&#xD;
          -  No longer than 24 hours since the time of death&#xD;
&#xD;
          -  Lived in Guatemala (exposure to fortified sugar)&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
          -  Aged &lt;10 years&#xD;
&#xD;
          -  Individuals with metabolic or nutritional conditions (diabetes, dyslipidemias, chronic&#xD;
             alcoholism, etc.)&#xD;
&#xD;
          -  Longer than 24 hours since the time of death&#xD;
&#xD;
          -  Not Guatemalan resident (Tourist, visitor etc.)&#xD;
      </textblock>
    </criteria>
    <gender>All</gender>
    <minimum_age>10 Years</minimum_age>
    <maximum_age>N/A</maximum_age>
    <healthy_volunteers>Accepts Healthy Volunteers</healthy_volunteers>
  </eligibility>
  <overall_official>
    <last_name>Francisco Chew, MD</last_name>
    <role>Principal Investigator</role>
    <affiliation>Institute of Nutrition of Central America and Panama</affiliation>
  </overall_official>
  <overall_official>
    <last_name>Erick Boy, MD, PhD</last_name>
    <role>Principal Investigator</role>
    <affiliation>HarvestPlus</affiliation>
  </overall_official>
  <overall_official>
    <last_name>Georg Lietz, PhD</last_name>
    <role>Study Director</role>
    <affiliation>Newcastle University</affiliation>
  </overall_official>
  <overall_contact>
    <last_name>Georg Lietz, PhD</last_name>
    <phone>00441912086893</phone>
    <email>georg.lietz@newcastle.ac.uk</email>
  </overall_contact>
  <overall_contact_backup>
    <last_name>Kieran Finney, BSc (Hons).</last_name>
    <phone>00441912081403</phone>
    <email>kieran.finney@newcastle.ac.uk</email>
  </overall_contact_backup>
  <location>
    <facility>
      <name>Hospital Roosevelt</name>
      <address>
        <city>Guatemala City</city>
        <zip>Zona 11</zip>
        <country>Guatemala</country>
      </address>
    </facility>
    <status>Recruiting</status>
    <contact>
      <last_name>Keyla Castellanos, MD</last_name>
      <email>knca9510@gmail.com</email>
    </contact>
    <contact_backup>
      <last_name>Francisco Chew, MD</last_name>
      <email>chewf5@gmail.com</email>
    </contact_backup>
    <investigator>
      <last_name>Francisco Chew, MD</last_name>
      <role>Principal Investigator</role>
    </investigator>
    <investigator>
      <last_name>Keyla Castellanos, MD</last_name>
      <role>Sub-Investigator</role>
    </investigator>
  </location>
  <location>
    <facility>
      <name>INCAP</name>
      <address>
        <city>Guatemala City</city>
        <zip>Zona 11</zip>
        <country>Guatemala</country>
      </address>
    </facility>
    <status>Recruiting</status>
    <contact>
      <last_name>Francisco Chew, MD</last_name>
      <email>chewf5@gmail.com</email>
    </contact>
    <contact_backup>
      <last_name>Keyla Castellanos, MD</last_name>
      <email>knca9510@gmail.com</email>
    </contact_backup>
    <investigator>
      <last_name>Francisco Chew, MD</last_name>
      <role>Principal Investigator</role>
    </investigator>
    <investigator>
      <last_name>Keyla Castellanos, MD</last_name>
      <role>Sub-Investigator</role>
    </investigator>
  </location>
  <location>
    <facility>
      <name>Hospital General San Juan de Dios</name>
      <address>
        <city>Guatemala City</city>
        <zip>Zona 1</zip>
        <country>Guatemala</country>
      </address>
    </facility>
    <status>Recruiting</status>
    <contact>
      <last_name>Keyla Castellanos, MD</last_name>
      <email>knca9510@gmail.com</email>
    </contact>
    <contact_backup>
      <last_name>Francisco Chew, MD</last_name>
      <email>chewf5@gmail.com</email>
    </contact_backup>
    <investigator>
      <last_name>Francisco Chew, MD</last_name>
      <role>Principal Investigator</role>
    </investigator>
    <investigator>
      <last_name>Keyla Castellanos, MD</last_name>
      <role>Sub-Investigator</role>
    </investigator>
  </location>
  <location>
    <facility>
      <name>Morgue del INACIF</name>
      <address>
        <city>Guatemala City</city>
        <zip>Zona 3</zip>
        <country>Guatemala</country>
      </address>
    </facility>
    <status>Recruiting</status>
    <contact>
      <last_name>Keyla Castellanos, MD</last_name>
      <email>knca9510@gmail.com</email>
    </contact>
    <contact_backup>
      <last_name>Francisco Chew, MD</last_name>
      <email>chewf5@gmail.com</email>
    </contact_backup>
    <investigator>
      <last_name>Francisco Chew, MD</last_name>
      <role>Principal Investigator</role>
    </investigator>
    <investigator>
      <last_name>Keyla Castellanos, MD</last_name>
      <role>Sub-Investigator</role>
    </investigator>
  </location>
  <location>
    <facility>
      <name>Newcastle University</name>
      <address>
        <city>Newcastle Upon Tyne</city>
        <state>Tyne And Wear</state>
        <zip>NE2 4HH</zip>
        <country>United Kingdom</country>
      </address>
    </facility>
    <status>Active, not recruiting</status>
  </location>
  <location_countries>
    <country>Guatemala</country>
    <country>United Kingdom</country>
  </location_countries>
  <reference>
    <citation>Pineda, O. (1998). Fortification of Sugar with Vitamin A. Food and Nutrition Bulletin, 19(2), 131-136.</citation>
  </reference>
  <reference>
    <citation>Ribaya-Mercado JD, Solomons NW, Medrano Y, Bulux J, Dolnikowski GG, Russell RM, Wallace CB. Use of the deuterated-retinol-dilution technique to monitor the vitamin A status of Nicaraguan schoolchildren 1 y after initiation of the Nicaraguan national program of sugar fortification with vitamin A. Am J Clin Nutr. 2004 Nov;80(5):1291-8. doi: 10.1093/ajcn/80.5.1291.</citation>
    <PMID>15531678</PMID>
  </reference>
  <reference>
    <citation>Olsen K, Suri DJ, Davis C, Sheftel J, Nishimoto K, Yamaoka Y, Toya Y, Welham NV, Tanumihardjo SA. Serum retinyl esters are positively correlated with analyzed total liver vitamin A reserves collected from US adults at time of death. Am J Clin Nutr. 2018 Nov 1;108(5):997-1005. doi: 10.1093/ajcn/nqy190.</citation>
    <PMID>30475970</PMID>
  </reference>
  <verification_date>February 2020</verification_date>
  <study_first_submitted>March 23, 2020</study_first_submitted>
  <study_first_submitted_qc>June 17, 2020</study_first_submitted_qc>
  <study_first_posted type="Actual">June 18, 2020</study_first_posted>
  <last_update_submitted>June 17, 2020</last_update_submitted>
  <last_update_submitted_qc>June 17, 2020</last_update_submitted_qc>
  <last_update_posted type="Actual">June 18, 2020</last_update_posted>
  <responsible_party>
    <responsible_party_type>Sponsor</responsible_party_type>
  </responsible_party>
  <keyword>Retinol</keyword>
  <keyword>Hypervitaminosis A</keyword>
  <keyword>Hepatic Vitamin A</keyword>
  <keyword>Guatemala</keyword>
  <condition_browse>
    <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
    <mesh_term>Night Blindness</mesh_term>
    <mesh_term>Vitamin A Deficiency</mesh_term>
    <mesh_term>Hypervitaminosis A</mesh_term>
  </condition_browse>
  <patient_data>
    <sharing_ipd>No</sharing_ipd>
  </patient_data>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT04438200
org study id: VDACS-MF-0109-2019
nct id: NCT04438200
lead sponsor: 
collaborator: 
collaborator: 
collaborator: 
collaborator: 
has dmc: No
is fda regulated drug: No
is fda regulated device: No
Guatemala has enforced mandatory fortification of sugar with vitamin A (VA) since June 1974
      and has led to a highly successful reduction in VA deficiency and associated disease.
      However, Ribaya-Mercado et al. 2014, estimated the biological impact of sugar fortified with
      retinyl palmitate that there may be a risk of chronic excess intake of preformed VA
      associated with programs of mass fortification. A recent food consumption survey in two
      departments in Guatemala found the average daily sugar intake in children under the age of
      two who aren´t being breastfed is 30.3 g, which translates into a daily intake of 272 μg of
      retinol (almost the full estimated average requirement (EAR) for that age group). Since data
      from the second National Survey on Micronutrients suggest a risk of VA toxicity, it is
      important to determine the levels of hepatic VA directly in corpses of individuals, of all
      ages, who have died of non-metabolic causes. Due to this, the investigators propose to assess
      liver and bone VA levels in combination with gene expression, histopathology and biochemical
      analyses, to elicit indications of hypervitaminosis A in Guatemala.
Objectives:

        1. To determine the post mortem concentration of hepatic and bone VA in corpses of
           adolescent, young and elderly adults as an indicator of exposure to dietary VA

        2. To assess the effect of high VA exposure on key enzymes in liver and bone tissue and to
           assess the risk of hypervitaminosis A in people exposed to compulsory mass vitamin A
           fortification program in Guatemala.

      Methodology:

      Setting and sampling The corpses for this study will be obtained from the National Institute
      of Forensic Sciences' (INACIF) departmental morgues in 2 hospitals in Guatemala City. The
      study population will be 150 cadavers sampled for VA tissue concentration; gene expression
      analysis combined with histopathology.

      Sample collection process and duration All samples will be collected during necropsies
      carried out at the INACIF forensic morgue. During necropsy, the liver will be weighed and the
      information recorded. A range of up to 10 x 3 g samples of the liver's right lobe will be
      obtained. Each sample will be properly labelled with previously prepared codes. Liver samples
      for histopathological analysis will be stored in 10% buffered formalin for 24 hours prior to
      transfer to ethanol before embedding, sectioning and staining. All samples collected for
      retinoid analysis will be frozen on dry ice in the morgue, transported as such to the
      laboratory and subsequently stored at -80˚C. Liver samples for gene expression analysis will
      be collected in RNAlater solution to protect RNA stability and subsequently stored at -80˚C
      until shipment to Newcastle University. The hepatic VA analysis will be done in Newcastle
      University using established High Perfromance Liquid Chromatography (HPLC) methods. Samples
      for analysis of gene expression will be sent on dry ice to Newcastle for RNA extraction and
      quantification. Since it is possible to obtain good quality RNA suitable for Quantitative
      Polymerase Chain Reaction (q-PCR) based analyses from post mortem tissue up to 72 hours after
      death, tissue samples stored in RNAlater within 24 hours of death will be adequate for gene
      expression analysis. Furthermore, experience from the investigators human biobank in
      Newcastle shows that tissue RNA can be extracted successfully after the demise of a patient
      up to 72 hours after death as long as the tissue has a pH of over 6. Gene expression of key
      regulatory proteins, such as LRAT and CYP26A1 will be performed in Newcastle. Choice of genes
      was based on the fact that LRAT may become saturated at very high levels of VA, leading to
      increasing levels of free circulating VA that can be metabolized to retinoic acid and other
      metabolites via CYP26A. Histopathological analysis will be carried out by pathologists in
      Guatemala with digitised slides being sent to the pathologist within Newcastle University -
      these slides will be analysed by both pathologists independently.

      Bone samples will also be obtained during the necropsy carried out at the INACIF forensic
      morgue. The iliac crest bone will be exposed by making an incision and removing the overlying
      soft tissue (skin, adipose tissue, connective tissue and muscle). The periosteum and cortical
      bone shall be removed via osteotomy exposing the spongy bone. Biopsy needles will be used to
      take samples from the spongy bone for analysis of tissue VA concentrations and gene
      expression, as previously described, at Newcastle University.

      All samples will be shipped to Newcastle University on dry ice.

      Study duration According to the information provided by INACIF 18 autopsies were performed
      between March and May 2013 on children less than one year of age, 24 on children from 1 to 4
      years old, 11 on children 5 to 9 years old, 51 on individuals from 10 to 14 years old, 281 on
      adolescents 15 to 19 years old, and 401 on young adults 20 to 24 years old. According to
      INACIF's forensic doctor, ~60% of the total number of autopsies carried out in Guatemala are
      performed in the capital city. The main causes of death in children under the age of 9 were
      head injuries and other types of trauma. Individuals from 10 to 24 years of age died mainly
      due to violence: firearms, stabbings, choking and different types of trauma.
observational model: Other
time perspective: Cross-Sectional
measure: Liver Vitamin A concentration
time frame: Enrolment
description: Liver Vitamin A concentration
measure: Liver Gene Expression
time frame: Enrolment
description: Gene expression associated with Vitamin A
measure: Liver Histology
time frame: Enrolment
description: Histological changes associated with Vitamin A
measure: Bone Gene Expression
time frame: Enrolment
description: Gene expression associated with Vitamin A
measure: Bone Vitamin A concentration
time frame: Enrolment
description: Bone Vitamin A concentration
arm group label: Adolescents
description: Individuals aged 10-19 years
arm group label: Young Adults
description: Individuals aged 20-39 years
arm group label: Elderly Adults
description: Individuals aged 40+ years
Liver Tissue Samples Bone Tissue Samples
study pop: 
sampling method: Non-Probability Sample
criteria: 
gender: All
minimum age: 10 Years
maximum age: N/A
healthy volunteers: Accepts Healthy Volunteers
last name: Francisco Chew, MD
role: Principal Investigator
affiliation: Institute of Nutrition of Central America and Panama
last name: Erick Boy, MD, PhD
role: Principal Investigator
affiliation: HarvestPlus
last name: Georg Lietz, PhD
role: Study Director
affiliation: Newcastle University
last name: Georg Lietz, PhD
phone: 00441912086893
email: georg.lietz@newcastle.ac.uk
last name: Kieran Finney, BSc (Hons).
phone: 00441912081403
email: kieran.finney@newcastle.ac.uk
facility: 
status: Recruiting
contact: 
contact backup: 
investigator: 
investigator: 
facility: 
status: Recruiting
contact: 
contact backup: 
investigator: 
investigator: 
facility: 
status: Recruiting
contact: 
contact backup: 
investigator: 
investigator: 
facility: 
status: Recruiting
contact: 
contact backup: 
investigator: 
investigator: 
facility: 
status: Active, not recruiting
country: Guatemala
country: United Kingdom
citation: Pineda, O. (1998). Fortification of Sugar with Vitamin A. Food and Nutrition Bulletin, 19(2), 131-136.
citation: Ribaya-Mercado JD, Solomons NW, Medrano Y, Bulux J, Dolnikowski GG, Russell RM, Wallace CB. Use of the deuterated-retinol-dilution technique to monitor the vitamin A status of Nicaraguan schoolchildren 1 y after initiation of the Nicaraguan national program of sugar fortification with vitamin A. Am J Clin Nutr. 2004 Nov;80(5):1291-8. doi: 10.1093/ajcn/80.5.1291.
PMID: 15531678
citation: Olsen K, Suri DJ, Davis C, Sheftel J, Nishimoto K, Yamaoka Y, Toya Y, Welham NV, Tanumihardjo SA. Serum retinyl esters are positively correlated with analyzed total liver vitamin A reserves collected from US adults at time of death. Am J Clin Nutr. 2018 Nov 1;108(5):997-1005. doi: 10.1093/ajcn/nqy190.
PMID: 30475970
responsible party type: Sponsor
mesh term: Night Blindness
mesh term: Vitamin A Deficiency
mesh term: Hypervitaminosis A
sharing ipd: No