Impact of Vitamin D on Heart Disease and Total Mortality

描述（由申请人提供）：关于维生素D （Vit D）缺乏对几种主要慢性疾病（如冠心病（CHD）和癌症）的不良影响，有相互矛盾的报道。据报道，维生素D缺乏症普遍存在，老年人尤为易感。在北美，维生素D的主要来源是阳光照射。强调避免阳光照射以降低患皮肤癌的风险可能会增加患冠心病的风险。利用Adventist Health Study-2问卷数据及全国10万名受试者，在5年的随访后，我们将进一步阐明血清25羟基维生素D(25- oh -D)（维生素D状态的最佳指标）与致死性冠心病和总死亡率之间的关系。我们将使用为校准研究收集的血液样本来确定实际的血清Vit D水平。然后将使用回归校准来预测血清25羟基维生素D的期望值，条件是暴露于膳食维生素D、钙摄入量、阳光和年龄。黑人的结果将与“白人”的结果进行比较，因为皮肤色素沉着减少了从前体转化为维生素D的活性形式的量。

DESCRIPTION (provided by applicant): There are conflicting reports regarding the adverse effects of Vitamin D (Vit D) deficiency on several major chronic diseases, such as coronary heart disease (CHD) and cancer. It is reported that hypovitaminosis D is widespread, the elderly being particularly susceptible. The main source of Vit D in North America is through sunlight exposure. The emphasis placed on protection from sunlight exposure to reduce skin cancer risk may be creating an increased risk for CHD. By using the Adventist Health Study-2 questionnaire data and its 100,000 subjects countrywide, we intend to further elucidate the relationships between serum 25 hydroxy Vit D(25-OH-D) (the best indicator of vit D status) and fatal CHD and total mortality after 5 years follow-up. We will use blood samples collected for the calibration study to determine actual serum Vit D levels. Regression calibration will then be used to predict expected values of serum 25 hydroxy Vit D conditional on exposures to dietary vit D, calcium intake, sunlight, and age. Results for blacks will be compared to those of "whites" because skin pigmentation reduces the amount of the active form of Vit D converted from precursors.