Melin A L, Wilske J, Ringertz H, Sääf M
Department of Primary Health Care, Research and Development Unit, Serafen, Stockholm, Sweden.
Aging (Milano). 1999 Jun;11(3):200-7.
The aim of this study was to determine vitamin D status and bone mineral density (BMD) in elderly, independent Scandinavians. A cross-sectional examination was conducted in a sample of 104 subjects (mean age 84.5 years), for possible correlations among anthropometric data, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, intact parathyroid hormone (PTH) and femoral neck BMD. Daily dietary calcium and vitamin D intakes were below the recommended levels. Five percent of the subjects were taking calcium, and 30% vitamin D supplements. Previous fragility fracture was reported in 30% of the men, and 55% of the women. Higher mean values of serum 25-hydroxyvitamin D (p = 0.03) and femoral neck BMD (p = 0.03) were recorded in subjects spending > or = 3 hours outdoors weekly. Independently of time spent outdoors, subjects taking daily supplements of vitamin D (on average 5 micrograms) had higher 25-hydroxyvitamin D (p < 0.001) levels, without significant changes in femoral neck BMD values. Serum levels of intact PTH (reference range 8-51 ng/L) were elevated in 41%, of which 5% had mild primary hyperparathyroidism. Serum levels of 25-hydroxyvitamin D (reference range 10-65 ng/mL) and 1,25-dihydroxyvitamin D (reference range 15-55 pg/mL) were below the reference ranges in 4% and 5% of the subjects, respectively. When serum levels of 25-hydroxyvitamin D were lower than approximately 30 ng/mL, the serum intact PTH values began to increase from a level of 43 pg/mL. This threshold most probably reflected a more relevant value of vitamin D insufficiency, indicating that 45% of our subjects rather than 4% actually had hypovitaminosis. Multiple regression analysis demonstrated femoral neck BMD to be significantly and positively associated with higher body mass index, male gender, no history of fragility fracture and 25-hydroxyvitamin D (R2 = 0.39). It is concluded that in this sample of healthy elderly people who regularly spend time outdoors, vitamin D levels leading to secondary hyperparathyroidism seem to be a major cause of osteoporosis. Correcting chronic dietary calcium deficiency is likely to eliminate another factor contributing to poor bone health.
本研究旨在确定独立生活的斯堪的纳维亚老年人的维生素D状况和骨矿物质密度（BMD）。对104名受试者（平均年龄84.5岁）进行了横断面检查，以探究人体测量数据、25-羟基维生素D、1,25-二羟基维生素D、完整甲状旁腺激素（PTH）和股骨颈骨密度之间可能存在的相关性。每日膳食钙和维生素D摄入量均低于推荐水平。5%的受试者正在服用钙补充剂，30%的受试者正在服用维生素D补充剂。据报告，30%的男性和55%的女性曾发生过脆性骨折。每周户外活动时间≥3小时的受试者血清25-羟基维生素D（p = 0.03）和股骨颈骨密度（p = 0.03）的平均值较高。无论户外活动时间长短，每日服用维生素D补充剂（平均5微克）的受试者25-羟基维生素D水平较高（p < 0.001），而股骨颈骨密度值无显著变化。41%受试者的血清完整PTH水平（参考范围8 - 51 ng/L）升高，其中5%患有轻度原发性甲状旁腺功能亢进。4%和5%的受试者血清25-羟基维生素D水平（参考范围10 - 65 ng/mL）和1,25-二羟基维生素D水平（参考范围15 - 55 pg/mL）分别低于参考范围。当血清25-羟基维生素D水平低于约30 ng/mL时，血清完整PTH值开始从43 pg/mL的水平上升。该阈值很可能反映了更具相关性的维生素D不足值，这表明我们的受试者中有45%而非4%实际上存在维生素D缺乏症。多元回归分析表明，股骨颈骨密度与较高的体重指数、男性性别、无脆性骨折病史以及25-羟基维生素D显著正相关（R2 = 0.39）。研究得出结论，在这个经常户外活动的健康老年人样本中，导致继发性甲状旁腺功能亢进的维生素D水平似乎是骨质疏松症的主要原因。纠正慢性膳食钙缺乏可能会消除另一个导致骨骼健康不佳的因素。
