School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK.
Obesity Action Scotland, Glasgow, UK.
Osteoporos Int. 2017 Dec;28(12):3361-3372. doi: 10.1007/s00198-017-4201-2. Epub 2017 Sep 15.
To determine how long vitamin D lasts after supplementation ceases, the marker of status was measured 2 and 3 years after a 1-year trial. Compared to placebo, the proportion of vitamin D-deficient women was still lower, if they had taken daily vitamin D3, after 2 years, indicating its longevity.
The purpose of this study was to determine longevity of vitamin D status following cessation of vitamin D3 supplementation, 2 and 3 years after a 1-year randomised, double-blind placebo controlled trial and to investigate possible predictive factors.
Caucasian non-smoking postmenopausal women randomised to ViCtORY (2009-2010), who had not taken vitamin D supplements since the trial ended, were invited to attend follow-up visits. Total 25-hydroxyvitamin D (25OHD) and 24,25-dihydroxyvitamin D (24,25OH2D) were measured by dual tandem mass spectrometry of serum samples following removal of protein and de-lipidation; the original randomised controlled trial (RCT) samples were re-analysed simultaneously. Vitamin D-binding protein (VDBP) was measured by monoclonal immunoassay.
In March 2012 and March 2013, 159 women (mean (SD) age 67.6 (2.1) years) re-attended, equally distributed between the original treatment groups: daily vitamin D3 (400 IU, 1000 IU) and placebo. One month after the RCT ended (March 2010), the proportion of women in placebo, 400 IU and 1000 IU vitamin D3 groups, respectively, with 25OHD < 25 nmol/L was 15, 0 and 0 (chi-square p < 0.001, n = 46, 44, 54). After 2 years (March 2012), it was 22, 4 and 4% (p = 0.002, n = 50, 48, 57); after 3 years, it was 23, 13 and 15% (p = 0.429, n = 48, 45, 52). The respective proportions of women with 24,25OH2D < 2.2 nmol/L were 50, 2 and 2% (1 month, p < 0.001, n = 46, 44, 54); 42, 33 and 12% (2 years, p = 0.002, n = 50, 48, 57); and 45, 27 and 29% (3 years, p = 0.138, n = 47, 45, 51). VDBP was a predictor of circulating 25OHD longevity (beta for VDBP in μg/mL 0.736; 95% CI 0.216-1.255, p = 0.006) but not 24,25OH2D.
Four hundred international units or 1000 IU of daily vitamin D3 showed benefits over placebo 2 years after supplementation ceased in keeping 25OHD > 25 nmol/L.
为了确定维生素 D 补充停止后其状态能维持多久，在为期 1 年的试验结束 2 和 3 年后测量了标志物。与安慰剂相比，如果服用了每日维生素 D3，2 年后维生素 D 缺乏的女性比例仍然较低，表明其具有长效性。
本研究的目的是确定在为期 1 年的随机、双盲安慰剂对照试验结束后停止维生素 D3 补充 2 和 3 年后维生素 D 状态的长效性，并探讨可能的预测因素。
邀请参加 ViCtORY（2009-2010 年）的白人非吸烟绝经后女性参加随访，这些女性在试验结束后没有服用维生素 D 补充剂。使用双串联质谱法对血清样本进行蛋白去除和去脂处理后，测量了总 25-羟维生素 D（25OHD）和 24,25-二羟维生素 D（24,25OH2D）；同时对原始随机对照试验（RCT）样本进行了重新分析。使用单克隆免疫测定法测量维生素 D 结合蛋白（VDBP）。
2012 年 3 月和 2013 年 3 月，159 名女性（平均年龄 67.6（2.1）岁）再次参加了研究，平均年龄为 67.6（2.1）岁，她们在原始治疗组之间均等分布：每日维生素 D3（400 IU、1000 IU）和安慰剂。在 RCT 结束后的 1 个月（2010 年 3 月），安慰剂组、400 IU 和 1000 IU 维生素 D3 组中 25OHD<25 nmol/L 的女性比例分别为 15%、0%和 0%（卡方检验 p<0.001，n=46、44、54）。2 年后（2012 年 3 月），分别为 22%、4%和 4%（p=0.002，n=50、48、57）；3 年后，分别为 23%、13%和 15%（p=0.429，n=48、45、52）。24,25OH2D<2.2 nmol/L 的女性比例分别为 50%、2%和 2%（1 个月，p<0.001，n=46、44、54）；42%、33%和 12%（2 年，p=0.002，n=50、48、57）；和 45%、27%和 29%（3 年，p=0.138，n=47、45、51）。VDBP 是循环 25OHD 长效性的预测因子（VDBP 每微克/毫升的β值为 0.736；95%CI 0.216-1.255，p=0.006），但不是 24,25OH2D。
400 国际单位或 1000 IU 的每日维生素 D3 在停止补充后 2 年对安慰剂具有益处，可使 25OHD>25 nmol/L。
