Carmel R, Green R, Jacobsen D W, Rasmussen K, Florea M, Azen C
Department of Medicine, New York Methodist Hospital, Brooklyn, NY, USA.
Am J Clin Nutr. 1999 Nov;70(5):904-10. doi: 10.1093/ajcn/70.5.904.
Low cobalamin concentrations and mild hyperhomocysteinemia are common in the elderly but ethnic differences have not been defined.
Our objective was to determine the demographic characteristics of cobalamin deficiency in the elderly and its role in their hyperhomocysteinemia.
We measured serum cobalamin, total homocysteine (Hcys), and methylmalonic acid (MMA) concentrations in 725 subjects >60 y old, and folate concentrations in 520 subjects.
After exclusion of subjects taking cobalamin supplements or with renal insufficiency, high prevalences of low cobalamin (11.8%), high MMA (16.6%), and high Hcys (26.1%) concentrations were seen. Most cobalamin concentrations <140 pmol/L appeared to reflect deficiency because 78. 3% of them were accompanied by abnormal metabolites. Subjects with cobalamin concentrations of 140-258 pmol/L had significantly fewer metabolic abnormalities. A low cobalamin concentration and renal insufficiency were the strongest predictors of abnormal Hcys concentrations. Elderly men had higher Hcys concentrations than did women (P = 0.0001). Whites and Latin Americans had lower cobalamin concentrations than did blacks and Asian Americans (P < 0.005). Whites also had higher Hcys concentrations than all the other groups (P < 0.05). When included in the analysis, renal insufficiency in subjects was associated with 23.8% of all high Hcys and 25.5% of all high MMA concentrations; most with renal insufficiency were Asian American and black men.
Mild cobalamin deficiency is most common in elderly white men and least common in black and Asian American women. Hyperhomocysteinemia, which is most strongly associated with low cobalamin concentrations, is also most common in elderly whites, whereas that associated with renal insufficiency is more common in blacks and Asian Americans. Ethnic differences in cobalamin deficiency and the Hcys patterns associated with it or with renal insufficiency warrant consideration in supplementation strategies. Extending suspicion of deficiency to persons with cobalamin concentrations of 140-258 pmol/L appears to provide more disadvantages than advantages.
老年人中钴胺素浓度低和轻度高同型半胱氨酸血症很常见，但种族差异尚未明确。
我们的目的是确定老年人钴胺素缺乏的人口统计学特征及其在高同型半胱氨酸血症中的作用。
我们测量了725名60岁以上受试者的血清钴胺素、总同型半胱氨酸（Hcys）和甲基丙二酸（MMA）浓度，以及520名受试者的叶酸浓度。
排除服用钴胺素补充剂或患有肾功能不全的受试者后，发现低钴胺素（11.8%）、高MMA（16.6%）和高Hcys（26.1%）浓度的患病率很高。大多数钴胺素浓度<140 pmol/L似乎反映了缺乏，因为其中78.3%伴有代谢物异常。钴胺素浓度为140 - 258 pmol/L的受试者代谢异常明显较少。低钴胺素浓度和肾功能不全是Hcys浓度异常的最强预测因素。老年男性的Hcys浓度高于女性（P = 0.0001）。白人和拉丁裔美国人的钴胺素浓度低于黑人和亚裔美国人（P < 0.005）。白人的Hcys浓度也高于所有其他组（P < 0.05）。纳入分析时，受试者的肾功能不全与所有高Hcys的23.8%和所有高MMA浓度的25.5%相关；大多数患有肾功能不全的是亚裔美国人和黑人男性。
轻度钴胺素缺乏在老年白人男性中最常见，在黑人和亚裔美国女性中最不常见。与低钴胺素浓度最密切相关的高同型半胱氨酸血症在老年白人中也最常见，而与肾功能不全相关的高同型半胱氨酸血症在黑人和亚裔美国人中更常见。钴胺素缺乏及其相关的或与肾功能不全相关的Hcys模式的种族差异在补充策略中值得考虑。将缺乏的怀疑范围扩大到钴胺素浓度为140 - 258 pmol/L的人似乎弊大于利。
