Van Guelpen Bethany, Hultdin Johan, Johansson Ingegerd, Stegmayr Birgitta, Hallmans Göran, Nilsson Torbjörn K, Weinehall Lars, Witthöft Cornelia, Palmqvist Richard, Winkvist Anna
Department of Medical Biosciences, Umeå University Hospital, Umeå, Sweden.
Stroke. 2005 Jul;36(7):1426-31. doi: 10.1161/01.STR.0000169934.96354.3a. Epub 2005 Jun 2.
Folate metabolism has been implicated in stroke. However, the possibility of a role for folate and vitamin B12, independent of their effects on homocysteine status, remains to be explored. The aim of this prospective, nested case-referent study was to relate plasma and dietary intake levels of folate and vitamin B12 to risk of stroke, taking into consideration plasma homocysteine concentrations and methylenetetrahydrofolate reductase polymorphisms.
Subjects were 334 ischemic and 62 hemorrhagic stroke cases and matched double referents from the population-based Northern Sweden Health and Disease Cohort.
Plasma folate was statistically significantly associated with risk of hemorrhagic stroke in an inverse linear manner, both in univariate analysis and after adjustment for conventional risk factors including hypertension (odds ratio [OR] for highest versus lowest quartile 0.21 (95% confidence interval [CI], 0.06 to 0.71; P for trend=0.008)). Risk estimates were attenuated by inclusion of homocysteine in the model (OR, 0.34; 95% CI, 0.08 to 1.40; P for trend=0.088). A similar pattern was observed for increasing folate intake (multivariate OR, 0.07; 95% CI, 0.01 to 0.55; P for trend=0.031 without homocysteine, and OR, 0.16, 95% CI, 0.02 to 1.23; P for trend=0.118 with homocysteine in the analysis). We found little evidence of an association between plasma or dietary folate and risk of ischemic stroke. Neither plasma nor dietary vitamin B12 was associated with risk of either stroke subtype.
The results of this study suggest a protective role for folate, possibly in addition to its effects on homocysteine status, in hemorrhagic but not ischemic stroke.
叶酸代谢与中风有关。然而，叶酸和维生素B12独立于其对同型半胱氨酸水平影响的作用可能性仍有待探索。这项前瞻性巢式病例对照研究的目的是在考虑血浆同型半胱氨酸浓度和亚甲基四氢叶酸还原酶多态性的情况下，将血浆和膳食中叶酸及维生素B12的摄入量与中风风险联系起来。
研究对象为334例缺血性中风和62例出血性中风患者，以及来自瑞典北部基于人群的健康与疾病队列研究中的匹配的两组对照。
在单变量分析以及对包括高血压在内的传统风险因素进行调整后，血浆叶酸与出血性中风风险呈统计学显著的负线性相关（最高四分位数与最低四分位数的比值比[OR]为0.21（95%置信区间[CI]，0.06至0.71；趋势P值 = 0.008））。在模型中纳入同型半胱氨酸后，风险估计值有所减弱（OR，0.34；95% CI，0.08至1.40；趋势P值 = 0.088）。叶酸摄入量增加时观察到类似模式（多变量OR，0.07；95% CI，0.01至0.55；分析中不包括同型半胱氨酸时趋势P值 = 0.031，包括同型半胱氨酸时OR，0.16，95% CI，0.02至1.23；趋势P值 = 0.118）。我们几乎没有发现血浆或膳食叶酸与缺血性中风风险之间存在关联的证据。血浆和膳食维生素B12均与任何一种中风亚型的风险无关。
本研究结果表明，叶酸可能除了对同型半胱氨酸水平有影响外，在出血性中风而非缺血性中风中具有保护作用。
