van Asselt D Z, de Groot L C, van Staveren W A, Blom H J, Wevers R A, Biemond I, Hoefnagels W H
Department of Geriatric Medicine, University Hospital Nijmegen, The Netherlands.
Am J Clin Nutr. 1998 Aug;68(2):328-34. doi: 10.1093/ajcn/68.2.328.
The reason for the high prevalence of mild cobalamin (vitamin B-12) deficiency in the elderly is poorly understood.
We aimed to determine the reason for this high prevalence.
We examined cobalamin intake, the presence and severity of atrophic gastritis, the presence of Helicobacter pylori infection, and plasma cobalamin and methylmalonic acid (MMA) concentrations in 105 healthy, free-living, older subjects aged 74-80 y.
Mild cobalamin deficiency, ie, low to low-normal plasma cobalamin concentrations (< 260 pmol/L) and elevated plasma MMA concentrations (> 0.32 micromol/L), were found in 23.8% of subjects; 25.7% of subjects were not cobalamin deficient (plasma cobalamin > or = 260 pmol/L and plasma MMA < or = 0.32 micromol/L). Six subjects (5.8%), including 1 with mild cobalamin deficiency, had dietary cobalamin intakes below the Dutch recommended dietary intake of 2.5 microg/d. Mildly cobalamin-deficient subjects had lower total (diet plus supplements) cobalamin intakes (median: 4.9 microg/d; 25th and 75th percentiles: 3.9, 6.4) than did non-cobalamin-deficient subjects (median: 6.3 microg/d; 25th and 75th percentiles: 5.4, 7.9) (P = 0.0336), mainly because of less frequent use of cobalamin supplements (8% compared with 29.6%; chi2 = 3.9, P = 0.048). Atrophic gastritis was found in 32.4% of the total study group: mild to moderate in 19.6% and severe in 12.7%. The prevalence of severe atrophic gastritis, but not mild-to-moderate atrophic gastritis, was higher in mildly cobalamin-deficient subjects (25%) than in non-cobalamin-deficient subjects (3.7%) (chi2 = 4.6, P = 0.032). The prevalence of immunoglobulin G antibodies to H. pylori was similar in mildly cobalamin-deficient subjects (54.2%) and in non-cobalamin-deficient subjects (44.4%) (chi2 = 0.5, P = 0.5).
The high prevalence of mild cobalamin deficiency in healthy, free-living, older Dutch subjects could be explained by inadequate cobalamin intake or severe atrophic gastritis in only 28% of the study population. Other mechanisms explaining mild cobalamin deficiency in older people must be sought.
老年人中轻度钴胺素（维生素B - 12）缺乏症的高患病率原因尚不清楚。
我们旨在确定这种高患病率的原因。
我们检测了105名年龄在74 - 80岁、健康、自由生活的老年人的钴胺素摄入量、萎缩性胃炎的存在及严重程度、幽门螺杆菌感染情况、血浆钴胺素和甲基丙二酸（MMA）浓度。
23.8%的受试者存在轻度钴胺素缺乏，即血浆钴胺素浓度低至正常低限（< 260 pmol/L）且血浆MMA浓度升高（> 0.32 μmol/L）；25.7%的受试者不存在钴胺素缺乏（血浆钴胺素≥260 pmol/L且血浆MMA≤0.32 μmol/L）。6名受试者（5.8%），包括1名轻度钴胺素缺乏者，其膳食钴胺素摄入量低于荷兰推荐膳食摄入量2.5 μg/d。轻度钴胺素缺乏的受试者总（膳食加补充剂）钴胺素摄入量（中位数：4.9 μg/d；第25和第75百分位数：3.9，6.4）低于非钴胺素缺乏的受试者（中位数：6.3 μg/d；第25和第75百分位数：5.4，7.9）（P = 0.0336），主要原因是较少使用钴胺素补充剂（8%对比29.6%；χ2 = 3.9，P = 0.048）。在整个研究组中，32.4%的人存在萎缩性胃炎：轻度至中度的占19.6%，重度的占12.7%。轻度钴胺素缺乏的受试者中重度萎缩性胃炎的患病率（25%）高于非钴胺素缺乏的受试者（3.7%），但轻度至中度萎缩性胃炎的患病率无差异（χ2 = 4.6，P = 0.032）。轻度钴胺素缺乏的受试者中幽门螺杆菌免疫球蛋白G抗体的患病率（54.2%）与非钴胺素缺乏的受试者（44.4%）相似（χ2 = 0.5，P = 0.5）。
在健康、自由生活的荷兰老年受试者中，轻度钴胺素缺乏的高患病率仅有28%可通过钴胺素摄入不足或严重萎缩性胃炎来解释。必须寻找其他解释老年人轻度钴胺素缺乏的机制。
