Hypovitaminosis D and K are Highly Prevalent and Independent of Overall Malnutrition in the Institutionalized Elderly

居住機構中的老年人有高盛行率的維生率D及維生素K缺乏症且與整體的營養不良無相關

10.6133/apjcn.2010.19.1.07

Akiko Kuwabara；Masako Himeno；Naoko Tsugawa；Maya Kamao；Minori Fujii；Nobuko Kawai；Miyuki Fukuda；Yoko Ogawa；Shoko Kido；Toshio Okano；Kiyoshi Tanaka

維生素D缺乏 ； 維生素K缺乏 ； 主成份分析 ； 足夠攝取量 ； 機構中的老年人 ； hypovitaminosis D ； hypovitaminosis K ； principal component analysis ； adequate intake ； institutionalized elderly

Asia Pacific Journal of Clinical Nutrition

19卷1期（2010 / 03 / 01）

49 - 56

英文

研究老年人的維生素D及維生素K缺乏症有許多方法學上的問題。首先，大多研究是藉由評估食物的攝取或是測量血中的濃度來進行的，但在日本很少同時利用這兩種方法。在本篇文章中，維生素D及維生素K的攝取以及老年人的血中濃度是同步測量的。第二個議題是維生素D及維生素K缺乏症是否與盛行於老年人的一般營養不良情形相關。我們試著藉由統計的主成份分析方法去分辨。評估50位機構中的老年人血中的25-羥化維生素D、副甲狀腺素、維生素K1、維生素K2濃度，以及食物攝取。雖然平均維生素D攝取量（每天7克）超過日本所訂定的足夠攝取量（每天5克），但平均血清中25-羥化維生素D濃度（11.1 ng/mL）卻屬維生素D缺乏的範圍。維生素K攝取量的中位數為每天168克，這幾乎是維生素K的足夠攝取量的2.5倍。但是，血漿中維生素K1及維生素K2濃度是遠低於70歲以上健康的日本老人。應用主成份分析法，結果產生4個成份，分別代表整體營養狀況、維生素K2、維生素D及維生素K1的營養狀況。既然每個成份都各自獨立，則這些老人的維生素D及維生素K缺乏不能用整體營養不良加以解釋。總之，在這些機構中的老年人具有高盛行率的維生素D及維生素K缺乏；爾後這類研究應該同時測量血中濃度及飲食攝取。主成份分析法，可排除橫斷性研究中其他干擾因子的作用，而得到有效的結果。

There have been methodological problems for studying hypovitaminosis D and K in the elderly. First, studies were done either by evaluating food intake or measuring their circulating levels, but rarely by both in Japan. In this paper, vitamin D and K intakes and their circulating levels were simultaneously determined. Second issue is whether hypovitaminosis D and K are independent of general malnutrition, prevalent in the elderly. We tried to statistically discriminate them by principal component analysis (PCA). Fifty institutionalized elderly were evaluated for their circulating 25 hydroxy-vitamin D (25OH-D), intact parathyroid hormone (PTH), phylloquinone (PK), menaquinone-7 (MK-7) levels, and their food intake. Although average vitamin D intake (7.0 μg/day) exceeded the Japanese Adequate Intake (AI) of 5.0 μg/day, average serum 25OH-D concentration was in the hypovitaminosis D range (11.1 ng/mL). Median vitamin K intake was 168 μg/day, approximately 2.5 times as high as AI for vitamin K. Nevertheless, plasma PK and MK-7 concentrations were far lower than those of healthy Japanese elderly over 70 years old. PCA yielded four components; each representing overall nutritional, vitamin K2, vitamin D, and vitamin K1 status, respectively. Since these components are independent of each other, vitamin D- and K-deficiency in these subjects could not be explained by overall malnutrition alone. In summary, institutionalized elderly had a high prevalence of hypovitaminosis D and K, and the simultaneous determination of their circulating level and dietary intake is mandatory in such studies. PCA would yield fruitful results for eliminating the interference by confounders in a cross-sectional study.