Moore Allan, Ryan Jude, Watts Michael, Pillay Isweri, Clinch David, Lyons Declan
Dept. of Medical Gerontology, Clinical Age Assessment Unit, Mid-Western Regional Hospital, Limerick, Republic of Ireland.
Clin Auton Res. 2004 Apr;14(2):67-71. doi: 10.1007/s10286-004-0142-x.
Orthostatic hypotension (OH) and vitamin B12 deficiency are common disorders in older people. Several case series have reported an association between vitamin B12 deficiency and OH. The effect of vitamin B12 replacement on this dysfunction has not been studied. We prospectively studied responses to head up tilt in patients over 70 years with vitamin B12 deficiency (intervention group) and compared their responses after replacement to those of matched patients with idiopathic OH and normal serum vitamin B12 concentrations (control group). Blood pressure (BP), heart rate (HR) and systemic vascular resistance (SVR) changes during orthostatic stress were evaluated using digital artery photoplethysmography. Eight patients and eight controls were studied. Initial head up tilt produced a mean BP decrease of 44/29 mmHg (s.e.m. 4/4 mmHg) in the intervention group and 33/12 mmHg (s.e.m. 3/2 mmHg) in the control group. Repeat head up tilt 6 months after vitamin B12 replacement produced a mean BP decrease of 15/9 mmHg (s.e.m. 5/2 mmHg) in the intervention group. The mean decrease in the control group was 30/12 mmHg (s.e.m. 2/2 mmHg). The difference in BP decreases between groups was statistically significant for both systolic and diastolic BP (p < 0.001 for both systolic BP and diastolic BP). Mean SVR in the intervention group decreased by 658 dynes/cm5/sec (s.e.m. 74 dynes/cm5/sec) during initial head up tilt. Mean SVR during repeat head up tilt decreased by 79 dynes/cm5/sec (s. e. m. 12 dynes/cm5/sec). Mean SVR in the control group decreased by 158 dynes/cm5/sec (s. e. m. 10 dynes/cm5/sec) during initial head up tilt and by 258 dynes/cm5/sec (s. e. m. 31 dynes/cm5/sec). The difference in SVR changes between groups was statistically significant (p = 0.02). We conclude that replacing vitamin B12 in older patients with vitamin B12 deficiency is associated with improved orthostatic tolerance to head up tilt.
直立性低血压（OH）和维生素B12缺乏是老年人常见的病症。几个病例系列报告了维生素B12缺乏与OH之间的关联。维生素B12替代治疗对这种功能障碍的影响尚未得到研究。我们前瞻性地研究了70岁以上维生素B12缺乏患者（干预组）对头部抬高倾斜试验的反应，并将替代治疗后的反应与匹配的特发性OH且血清维生素B12浓度正常的患者（对照组）进行比较。使用数字动脉光电容积描记法评估直立应激期间的血压（BP）、心率（HR）和全身血管阻力（SVR）变化。共研究了8例患者和8例对照。初始头部抬高倾斜试验时，干预组平均血压下降44/29 mmHg（标准误4/4 mmHg），对照组平均血压下降33/12 mmHg（标准误3/2 mmHg）。维生素B12替代治疗6个月后重复头部抬高倾斜试验，干预组平均血压下降15/9 mmHg（标准误5/2 mmHg）。对照组平均下降30/12 mmHg（标准误2/2 mmHg）。两组收缩压和舒张压下降幅度的差异均具有统计学意义（收缩压和舒张压p均<0.001）。干预组初始头部抬高倾斜试验期间平均SVR下降658达因/cm5/秒（标准误74达因/cm5/秒）。重复头部抬高倾斜试验期间平均SVR下降79达因/cm5/秒（标准误12达因/cm5/秒）。对照组初始头部抬高倾斜试验期间平均SVR下降158达因/cm5/秒（标准误10达因/cm5/秒），重复试验期间下降258达因/cm5/秒（标准误31达因/cm5/秒）。两组SVR变化的差异具有统计学意义（p = 0.02）。我们得出结论，在维生素B12缺乏的老年患者中补充维生素B12与改善头部抬高倾斜试验的直立耐受性有关。
