Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark.
J Alzheimers Dis. 2021;79(4):1601-1612. doi: 10.3233/JAD-201096.
It is controversial whether B12 deficiency causes dementia or B12 treatment can prevent dementia.
To assess associations between low plasma (P-)B12 levels, B12 treatment, and risk of Alzheimer's disease (AD; primary outcome) and all-cause or vascular dementia (secondary outcomes).
We conducted a population-based cohort study using Danish registry data to assess associations between low P-B12 levels, high-dose injection or oral B12 treatment, and risk of dementia (study period 2000-2013). The primary P-B12 cohort included patients with a first-time P-B12 measurement whose subsequent B12 treatment was recorded. The secondary B12 treatment cohort included patients with a first-time B12 prescription and P-B12 measurement within one year before this prescription. For both cohorts, patients with low P-B12 levels (<200 pmol/L) were propensity score-matched 1:1 with patients with normal levels (200-600 pmol/L). We used multivariable Cox regression to compute 0-15-year hazard ratios for dementia.
For low P-B12 and normal P-B12 level groups, we included 53,089 patients in the primary P-B12 cohort and 13,656 patients in the secondary B12 treatment cohort. In the P-B12 cohort, hazard ratios for AD centered around one, regardless of follow-up period or treatment during follow-up. In the B12 treatment cohort, risk of AD was unaffected by low pre-treatment P-B12 levels, follow-up period and type of B12 treatment. Findings were similar for all-cause and vascular dementia.
We found no associatio1n between low P-B12 levels and dementia. Associations were unaffected by B12 treatment. Results do not support routine screening for B12 deficiency in patients with suspected dementia.
维生素 B12 缺乏是否会导致痴呆，以及 B12 治疗能否预防痴呆，这一直存在争议。
评估低血浆（P-）B12 水平、B12 治疗与阿尔茨海默病（AD；主要结局）以及全因性或血管性痴呆（次要结局）风险之间的关联。
我们开展了一项基于人群的队列研究，使用丹麦注册数据评估低 P-B12 水平、高剂量注射或口服 B12 治疗与痴呆风险之间的关联（研究期间为 2000-2013 年）。主要 P-B12 队列纳入了首次 P-B12 检测且随后记录有 B12 治疗的患者。次要 B12 治疗队列纳入了首次开具 B12 处方且在该处方前一年内进行过 P-B12 检测的患者。对于两个队列，低 P-B12 水平（<200 pmol/L）患者与正常水平（200-600 pmol/L）患者按倾向评分 1:1 匹配。我们使用多变量 Cox 回归计算痴呆的 0-15 年风险比。
在主要 P-B12 队列和次要 B12 治疗队列中，低 P-B12 和正常 P-B12 水平组分别纳入了 53089 名患者和 13656 名患者。在 P-B12 队列中，无论随访时间或随访期间的治疗如何，AD 的风险比都接近 1。在 B12 治疗队列中，低治疗前 P-B12 水平、随访时间和 B12 治疗类型均不会影响 AD 的风险。全因性和血管性痴呆也有类似的发现。
我们未发现低 P-B12 水平与痴呆之间存在关联。B12 治疗不会影响这种关联。结果不支持对疑似痴呆患者常规筛查 B12 缺乏症。
