筛查存在争议,但在决定进行维生素 B12 缺乏检查前,临床医生应当将某些危险因素考虑在内。
随着年龄增大,罹患维生素 B12 缺乏的危险增加。[4]Pennypacker LC, Allen RH, Kelly JP, et al. High prevalence of cobalamin deficiency in elderly outpatients. J Am Geriatr Soc. 1992 Dec;40(12):1197-204.http://www.ncbi.nlm.nih.gov/pubmed/1447433?tool=bestpractice.com[5]Clarke R, Grimley Evans J, Schneede J, et al. Vitamin B12 and folate deficiency in later life. Age Ageing. 2004 Jan;33(1):34-41.http://ageing.oxfordjournals.org/cgi/reprint/33/1/34http://www.ncbi.nlm.nih.gov/pubmed/14695861?tool=bestpractice.com[6]Andres E, Loukili NH, Noel E, et al. Vitamin B12 (cobalamin) deficiency in elderly patients. CMAJ. 2004 Aug 3;171(3):251-9.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC490077/http://www.ncbi.nlm.nih.gov/pubmed/15289425?tool=bestpractice.com[7]Pfisterer KJ, Sharratt MT, Heckman GG, et al. Vitamin B12 status in older adults living in Ontario long-term care homes: prevalence and incidence of deficiency with supplementation as a protective factor. Appl Physiol Nutr Metab. 2016 Feb;41(2):219-22.http://www.ncbi.nlm.nih.gov/pubmed/26781161?tool=bestpractice.com
长期应用某些药物,例如二甲双胍、质子泵抑制剂和抗惊厥药也可使患者面临维生素 B12 缺乏的风险。
营养不良或素食者和素食有维生素缺乏的风险,可监测血清维生素水平。
存在可能引起维生素 B12 吸收不良或吸收不充分的慢性胃肠疾病(例如,克罗恩病、乳糜泻)的患者,以及曾接受胃部手术或末端回肠切除术的患者应接受筛查。
诊断为糖尿病多发神经病变 (DPN) 或 DPN 恶化的患者, 并发维生素 B12 缺乏的风险增加。[52]Wile DJ, Toth C. Association of metformin, elevated homocysteine, and methylmalonic acid levels and clinically worsened diabetic peripheral neuropathy. Diabetes Care. 2010 Jan;33(1):156-61.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2797962/http://www.ncbi.nlm.nih.gov/pubmed/19846797?tool=bestpractice.com
恶性贫血患者罹患胃癌的危险增加 2 至 3 倍,这些患者应随访内镜检查。[53]Hsing AW, Hansson LE, McLaughlin JK, et al. Pernicious anemia and subsequent cancer: a population-based cohort study. Cancer. 1993 Feb 1;71(3):745-50.http://www.ncbi.nlm.nih.gov/pubmed/8431855?tool=bestpractice.com