有益胆固醇降低中风风险

纽约，纽约 - 6月4日，2001年 - 高水平所谓的“好”胆固醇在血液中大大降低了老年白人，黑人和西班牙裔人群中风的风险，哥伦比亚研究人员已经发现。该发现增加了日益增长的证据，即健康行为，如运动，减肥，吸烟和中度酒精使用可能有助于预防卒中。该研究还强调了累积数据，显示更广泛使用胆固醇管理药物，称为他汀类药物，可以挽救生命。胆固醇是一种蜡质，身体用于通过血液运输脂肪的蜡质。有两种类型：“良好”胆固醇，称为高密度脂蛋白胆固醇（HDL-C），其“坏”对应，低密度脂蛋白胆固醇（LDL-C）。LDL胆固醇被称为糟糕，因为高水平的IT促进动脉堵塞，导致心脏病发作或中风。但HDL胆固醇与相反的效果有关，可能是因为它有助于从血液中清除“坏”胆固醇。过去的研究发现，高HDL胆固醇水平降低了心脏病的风险，但很少出版的研究表明它也降低了卒中风险。在哥伦比亚的研究中，要在6月6日发表的美国医学会期刊，研究人员在曼哈顿北部1,444名居民中研究了这一效果。“这是一个艰难的风险，”领导研究员Ralph L. Sacco说。 “Prior studies have not been as clear about the relationship between cholesterol and stroke.” Dr. Sacco is associate professor of neurology and public health and associate chairman of neurology at Columbia University College of Physicians & Surgeons and associate director of the stroke division at Columbia Presbyterian Medical Center of New York-Presbyterian Hospital. “Stroke is a huge public health problem” with few treatments for severe cases, he added. “More emphasis needs to be placed on prevention.” Stroke is a death of brain tissue due to a lack of blood flow to the brain. The often disabling condition is responsible for 1 in 15 deaths in America yearly, according to the American Heart Association. Stroke disproportionately affects the elderly, blacks and Hispanics, who are among the fastest-growing segments of the population. The risk of stroke more than doubles with each passing decade after age 55, and black males are 50 percent more likely to die from stroke than white males, according to American Heart Association figures. The most common type of stroke is ischemic stroke, which occurs when a blood vessel is blocked. Ischemic stroke accounts for 4 in 5 cases of stroke, according to one study. The Columbia researchers found that among the groups studied, people with high levels of HDL cholesterol had a lower risk of ischemic stroke by almost half, 47 percent. It’s not clear why HDL cholesterol has this effect, said the study’s authors, but several explanations are possible. One is that HDL cholesterol helps to clear LDL cholesterol from the blood. LDL cholesterol is responsible for fatty buildups in arteries, a condition called atherosclerosis. Another possibility, the researchers said, is that HDL cholesterol prevents LDL cholesterol from reacting with oxygen, a chemical process that promotes atherosclerosis. Consistent with both explanations is the observation that the steepest risk reduction found in the study was associated with a type of stroke that results from atherosclerosis. For this type of stroke, HDL-cholesterol was associated with an 80 percent risk reduction, the authors said. The findings add to mounting evidence of the usefulness of cholesterol-management drugs called statins, the authors said. Statins have been shown to reduce the risk of heart disease and stroke, and experts say more Americans should take these drugs. Statins “mainly will reduce LDL, but also have some effect on HDL” cholesterol, said Dr. Sacco, which helps explain why statins lower the risk of stroke. The research was supported by grants from the National Institute of Neurological Disorders and Stroke, the General Clinical Research Center, and the Columbia Center for the Active Life of Minority Elders.

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