Clinical trial NCT00428649: Optimization of Selenoprotein P in Chinese Subjects
Official title: Optimization of Selenoprotein P in Chinese Subjects
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Selenium Deficiency
Keywords: Selenium supplements
Selenoprotein P
Optimization
Lead sponsor: Vanderbilt University
Sponsor class: OTHER
Collaborators: name: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
First posted: 2007-01-30
Enrollment: 98
Sex: ALL
Minimum age (years): 17
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: The purpose of this study is to determine the amount of selenium as selenomethionine that is required to optimize selenoprotein P in selenium-deficient Chinese subjects

Detailed description: Selenium is an essential nutrient. The Recommended Dietary Allowance (RDA) for selenium is considered to be the amount required to optimize plasma selenoproteins. There are two selenoproteins present in the plasma: selenoprotein P (Se-P) and glutathione peroxidase 3 (GPX-3). Although the amount of selenium required to optimize GPX-3 has been determined, the amount required to optimize Se-P in the plasma remains unknown. We aim to determine this amount by supplementing selenium deficient subjects with varying amounts of selenium as selenomethionine.

The study will take place in Mianning County, China, where selenium status is low. Approximately 150 people will be screened for eligibility to participate in this study. 98 subjects will be enrolled. Background information obtained from each participant will be: age, height, weight and smoking status.

Subjects will be randomized to a selenium supplement group. The selenium supplement will contain either 0, 20, 40, 60, 80, 100, or 120 µg of selenium as selenomethionine. A CDC worker will visit each participant daily to give them their selenium supplement. The CDC worker will watch them take their supplement and will ask if they have any unanticipated problems. Blood samples of 20 ml will be obtained at weeks 0, 4, 8, 12, 16, 20, 24, 32, and 40. Hair samples and 24-hr urine collections will be obtained at 0, 20 and 40 weeks. The total study duration is 40 weeks.

Eligibility criteria: Inclusion Criteria:

* aged 17 years or older
* healthy
* resident of Mianning County for at least 1 year
* hematocrit (PCV) of 30 or greater

Exclusion Criteria:

* subject has taken selenium supplements within the year prior to study
* subject plans to relocate during study

Primary outcomes:
measure: Plasma selenoprotein P levels at 0, 4, 8, 12, 16, 20, 24, 32, and 40 weeks
timeFrame: 40 weeks
Secondary outcomes:
measure: Total plasma selenium concentrations at 0, 4, 8, 12, 16, 20, 24, 32, and 40 weeks
timeFrame: 40 weeks
measure: Plasma glutathione peroxidase activity at 0, 4, 8, 12, 16, 20, 24, 32, and 40 weeks
timeFrame: 40 weeks
measure: 24hr urinary selenium excretion at 0, 20 and 40 weeks
timeFrame: 40 weeks
measure: Hair selenium levels at 0, 20 and 40 weeks
timeFrame: 40 weeks
Other outcomes:
Locations:
city: Chengdu
country: China
facility: Sichuan Center for Disease Control and Prevention (Sichuan CDC)
state: Sichuan
Study officials:
affiliation: Vanderbilt University
name: Raymond F Burk, M.D.
role: PRINCIPAL_INVESTIGATOR
affiliation: Sichuan CDC, Chengdu
name: Yiming Xia, Ph.D.
role: STUDY_DIRECTOR
References:
citation: Xia Y, Hill KE, Byrne DW, Xu J, Burk RF. Effectiveness of selenium supplements in a low-selenium area of China. Am J Clin Nutr. 2005 Apr;81(4):829-34. doi: 10.1093/ajcn/81.4.829.
citation: Casey CE, Guthrie BE, Friend GM, Robinson MF. Selenium in human tissues from New Zealand. Arch Environ Health. 1982 May-Jun;37(3):133-5. doi: 10.1080/00039896.1982.10667551.
citation: Xia Y, Hill KE, Li P, Xu J, Zhou D, Motley AK, Wang L, Byrne DW, Burk RF. Optimization of selenoprotein P and other plasma selenium biomarkers for the assessment of the selenium nutritional requirement: a placebo-controlled, double-blind study of selenomethionine supplementation in selenium-deficient Chinese subjects. Am J Clin Nutr. 2010 Sep;92(3):525-31. doi: 10.3945/ajcn.2010.29642. Epub 2010 Jun 23.