Department of Preventive Medicine and Biostatistics, F. Edward Hérbert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
Int J Vitam Nutr Res. 2024 Jun;94(3-4):198-209. doi: 10.1024/0300-9831/a000788. Epub 2023 Jul 20.
Vitamin B12 can lead to neurological deficits. We assessed whether the mean corpuscular volume (MCV) could be a sufficiently sensitive measurement for abnormal serum methylmalonic Acid (MMA) and total plasma homocysteine (tHCY) (biomarkers of vitamin B12 or folate deficiency) and if so, at what cutoff value. A total of 26,397 participants (12,730 males and 13,667 females) were included in the analysis. Weighted analysis was performed using NHANES data to calculate crude/adjusted associations between MCV-MMA/tHCY, using linear regression. Unadjusted odds ratios (OR) 95% CIs were estimated from logistic regression models. Receiver Operating Curve and the Youden Index were used to identify the MCV level that most accurately distinguished those with abnormal MMA and tHCY (dependent variables) from those without. A positive and significant correlation between MCV-MMA/tHCY was found in the general population between ages 18-85, 0.95 (95% C.I. 0.75-1.17) and 2.61 (95% C.I. 2.15-3.08). In pregnant women, for every unit increase in MCV there was a 19% increase in odds of abnormal MMA, OR 1.19 (95% C.I. 1.08-1.31), p=0.001 and the Area Under the Curve for MCV as a test for abnormal MMA was 78%. An MCV cutoff of 93.1 correctly identified abnormal MMA in pregnant women with 81% sensitivity and 77% specificity. In the general population the MCV test performed poorly in identifying abnormal MMA/tHCY. MCV is an inexpensive measurement that may be useful to screen asymptomatic pregnant women for vitamin B12 abnormalities. This may have a significant impact on reducing adverse neurological outcomes in their children.
维生素 B12 可导致神经功能缺损。我们评估平均红细胞体积（MCV）是否可以作为异常血清甲基丙二酸（MMA）和总血浆同型半胱氨酸（tHCY）（维生素 B12 或叶酸缺乏的生物标志物）的敏感测量指标，如果是，那么在什么截断值。共纳入 26397 名参与者（男性 12730 名，女性 13667 名）进行分析。使用 NHANES 数据进行加权分析，使用线性回归计算 MCV-MMA/tHCY 的粗值/调整值之间的关联。使用逻辑回归模型估计未经调整的比值比（OR）95%置信区间。接收者操作曲线和 Youden 指数用于确定最准确区分 MMA 和 tHCY 异常（因变量）和正常参与者的 MCV 水平。在年龄在 18-85 岁的一般人群中，MCV-MMA/tHCY 之间存在正相关，相关系数为 0.95（95%置信区间 0.75-1.17）和 2.61（95%置信区间 2.15-3.08）。在孕妇中，MCV 每增加一个单位，MMA 异常的几率就会增加 19%，OR 1.19（95%置信区间 1.08-1.31），p=0.001，MCV 作为 MMA 异常检测的曲线下面积为 78%。MCV 截值为 93.1 时，可正确识别孕妇 MMA 异常，灵敏度为 81%，特异性为 77%。在一般人群中，MCV 试验在识别 MMA/tHCY 异常方面效果不佳。MCV 是一种廉价的测量方法，可用于筛查无症状孕妇的维生素 B12 异常。这可能会对降低其子女的不良神经发育结局产生重大影响。
