維他命D過多 死亡率可能增加 【00:35】
Individual And Family Dental Plans Choose The Plan And Dentist For You 〔中央社〕研究人員警告，血液中的維他命D濃度過多與死亡率高有關。他們在「出人意外」的研究結果中聲稱，過多的維生素D，造成的傷害幾乎跟過少一樣。
丹麥研究人員進行的新研究發現，維他命D濃度相當高的人，死亡率會高出40%。
這項哥本哈根大學（University of Copenhagen）研究，是根據24萬7574位病人的血液樣本。他們的血液樣本是經由家庭醫師檢測。
不過，英國專家表示，英國有相反的問題，目前有1/4的民眾維他命D濃度低，可能有不足的危險。
這項研究是使用哥本哈根家庭醫師實驗室（Copenhagen General Practitioners Laboratory）血液樣本中，規模最大的一個。
研究發現，維他命D降至最低濃度和升至最高濃度時，與死亡率變高其間的關連性。
研究結果顯示，當血液中每公升的血清含有不到10nmol（10億分之一莫耳）的維他命D，死亡率就會增加超過1倍，是平均值的2.31倍高。
不過，如果血液中每公升的血清含有超過140nmol的維他命D，死亡率會多出1.42，大約高出40%。
發表在「臨床內分泌與代謝期刊」（Journal of Clinical Endocrinology and Metabolism）的研究報告說，維他命D含量為50nmol時，死亡率最低。
丹麥研究人員進行的新研究發現，維他命D濃度相當高的人，死亡率會高出40%。
這項哥本哈根大學（University of Copenhagen）研究，是根據24萬7574位病人的血液樣本。他們的血液樣本是經由家庭醫師檢測。
不過，英國專家表示，英國有相反的問題，目前有1/4的民眾維他命D濃度低，可能有不足的危險。
這項研究是使用哥本哈根家庭醫師實驗室（Copenhagen General Practitioners Laboratory）血液樣本中，規模最大的一個。
研究發現，維他命D降至最低濃度和升至最高濃度時，與死亡率變高其間的關連性。
研究結果顯示，當血液中每公升的血清含有不到10nmol（10億分之一莫耳）的維他命D，死亡率就會增加超過1倍，是平均值的2.31倍高。
不過，如果血液中每公升的血清含有超過140nmol的維他命D，死亡率會多出1.42，大約高出40%。
發表在「臨床內分泌與代謝期刊」（Journal of Clinical Endocrinology and Metabolism）的研究報告說，維他命D含量為50nmol時，死亡率最低。
Sun Exposure Not Enough to Correct Vitamin D Deficiency
March 17, 2012 (San Diego, California) — "The 'epidemic' in vitamin D deficiency is clearly not from too little sun exposure," and dermatologists can be confident in insisting that their patients continue their sun protection efforts, said Richard Gallo, MD, PhD, here at the American Academy of Dermatology (AAD) 70th Annual Meeting.
"Clearly solar exposure is an influence — there is no doubt about that — but you cannot predictably say that a certain amount of exposure will normalize vitamin D deficiency," said Dr. Gallo, chief of dermatology and professor of medicine and pediatrics at the University of California, San Diego, in an interview with Medscape Medical News.
Speaking to an overcapacity audience at the meeting's "Hot Topics" symposium, Dr. Gallo, who was involved in the 2010 Institute of Medicine's (IOM's) consensus report on updated dietary vitamin D intake recommendations, said that although "sunlight is a very reliable source of vitamin D, nutritional sources are clearly required and are, of course, much safer."
He said although there is strong evidence that vitamin D is "absolutely necessary" for bone health, other potential health benefits such as protection from cardiovascular events, cancer, and infection are, as yet, unproven.
Although some physicians advocate universal screening for vitamin D deficiency or insufficiency, Dr. Gallo said there is no evidence to support this approach, and there is a lack of consensus on the definition of these conditions.
The IOM report recommends that patients should have serum vitamin D levels above 20 ng/mL, but the American Endocrine Society sets this level at 30 ng/mL, Dr. Gallo said.
There is evidence to support screening in high-risk individuals, he added, and noted that this is an extensive list including all dark-skinned, pregnant or lactating, elderly, and obese individuals, as well as those with malabsorption syndromes, rickets, osteomalacia, osteoporosis, chronic kidney disease, granulomatous disorders and lymphomas, and patients receiving chronic antifungal therapy.
"This is a pretty broad spectrum of individuals, and it's kind of left up to the individual practitioner right now to use their common sense regarding who should be screened and who shouldn't," Dr. Gallo noted. Physicians who do find a deficiency on screening should consider checking parathyroid hormone, which can sometimes have a compensatory rise, he said.
"An elevated parathyroid hormone paired with low vitamin D and potentially low calcium could be high risk for bone disease. So those kinds of individuals on the severe [low] end you might be best to refer to an endocrinologist," he said in the interview.
"For individuals on the borderline, at 15 ng/mL (and a lot of individuals are there) a simple thing to do is to just suggest a vitamin supplement and rescreen them perhaps 3 to 6 months later."
Winter blood tests will naturally reflect lower levels than in the summer, he added.
Dr. Gallo have disclosed no relevant financial relationships.
American Academy of Dermatology (AAD) 70th Annual Meeting: Presented March 16, 2012.
Medscape Medical News © 2012 WebMD, LLC
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