Impact of Vitamin D on Heart Disease and Total Mortality

描述(申请人提供)：关于维生素D(VitD)缺乏对几种主要慢性疾病的不利影响，如冠心病和癌症，有相互矛盾的报告。据报道，维生素D缺乏症普遍存在，老年人尤其容易受到影响。在北美，维生素D的主要来源是阳光暴晒。强调防止暴露在阳光下以降低皮肤癌风险可能会增加冠心病的风险。通过使用基督复临安息日健康研究-2问卷数据及其在全国范围内的100,000名受试者，我们打算进一步阐明血清25-羟基维生素D(25-OH-D)(维生素D状态的最佳指标)与5年随访的致死性冠心病和总死亡率的关系。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维生素D水平。然后将使用回归校正来预测血清25羟基维生素D的期望值，条件是饮食中维生素D的暴露、钙的摄入量、阳光和年龄。黑人的结果将与“白人”的结果进行比较，因为皮肤色素沉着会减少前体转化为维生素D的活性形式的数量。

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.