Environmental Influences on Vitamin D Status
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 50
- 试验地点
- 1
- 主要终点
- To measure the prevailing 25D and Vitamin D levels in communities at diverse latitudes
研究概览
简要总结
Vitamin D deficiency is a common problem. The principal source of vitamin D for humans is solar exposure, with cutaneous synthesis of vitamin D by photoconversion of 7-dehydrocholesterol in the skin to pre-vitamin D3. Latitude, altitude, season, skin pigmentation, and age are recognized factors that influence how much vitamin D can be made by solar exposure. However, the relative influences of each are largely unknown and we cannot reliably answer the question of how much sun exposure an individual needs at various latitudes and at various seasons in order to ensure normal vitamin D status.
详细描述
Purpose of the study: To determine the effect of environmental influences on Vitamin D status.
Specific Aims
- To measure the prevailing 25D and Vitamin D levels in communities at diverse latitudes (Alaska and Hawaii).
- To collect information on variables that influence Vitamin D status such as skin color, history of sun exposure and sunscreen use, diet history, vitamin and calcium supplements used, and BMI.
- To collect typical food samples from the region for future analysis of their Vitamin D and 25D content.
- To collect a blood sample for DNA analysis of inter-individual differences in Vitamin D metabolism (Gc or Vitamin D binding protein alleles).
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Cross Sectional
入排标准
- 年龄范围
- 18 Years 至 60 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Able to consent and come for a study visit. Male or female males and females ages 18-60.
排除标准
- •Unable to consent or come to a visit, taking Vitamin D supplements, anticonvulsants, barbiturates, steroids, having granulomatous disease, or liver or kidney disease as these medications and conditions interfere with Vitamin D metabolism.
结局指标
主要结局
To measure the prevailing 25D and Vitamin D levels in communities at diverse latitudes
时间窗: crosssectional
次要结局
- 2. To collect information on variables that influence Vitamin D status such to collect information on skin color, history of sun exposure and sunscreen use, diet history, vitamin and calcium supplements used, and BMI.(cross sectional)
- To collect a blood sample for DNA analysis of inter-individual differences in Vitamin D metabolism (Gc or Vitamin D binding protein alleles).(cross sectional)