Study of cobalamine deficiency among advanced aged gastrectomized subjects

Objective: The objective of this study were: a) to investigate Vitamin B-12 deficiency among and advanced aged, clinically healthy, asymptomatic popul ation, presumably with a high prevalence of vitamin B-12 deficiency. This d eficiency was defined as an increase in the MMA/creatinine ratio in urine a nd/or basal plasma HT levels which normalize after the administration of vi tamin B-12; b) its relationship with plasma vitamin B-12 levels. Subjects and methods: A total of 45 subjects were studied, 19 in the Group of Gastrectomized patients, who were selected on the basis of an age over 6 0 years and partial gastrectomy of more than five years, and 26 in the Geri atric Group selected in two nursing homes. All of them were asymptopatic an d "healthy" according to data in the clinical records and clinical examinat ion, analytical studies, and none of them was taking any drug that might al ter results. After basal analytical studies, which included B-12, folates, metilmalonic acid/creatinine (MMA/creatinine) in urine and total plasma hom ocysteine (TH), i.m. vitamin B-12 was administered for 15 days to the gastr ectomized patients and oral B-12 for 28 days with 2.5 mg folic acid for the last 14 days to the patients in the Geriatric Group. Basal analytical stud ies were repeated at the end of the study. Results: Basal analytical studies were normal with the exception of two sub jects with low levels of hemoglobin and 8 with decreased MCV. Only one subj ect had decreased serum cobalamines. Nine subjects (20%) were identified wi th increased basal levels of MMA/creatinine which normalized after decreasi ng between 97% and 12% after the administration of vitamin B-12. TH and MCV also decreased significantly. Basal levels of vitamin B-12 ranged from 244 pg/ml to 483 pg/ml (n = 220 pg/ml-980 pg/ml). Conclusions: Vitamin B-12 deficiency, defined as an increase in the MMA/cre atinine ratio and TH normalized with B-12, is highly prevalent among elderl y subjects and may occurr in absence of clinical and/or analytical manifest ations. Given the widespread recommendation of quantitating MMA and TH for the diagnosis of borderline cases of vitamin B-12 deficiency, such disturba nce may occur in clinically and biochemically normal subjects. Thus, a spec ial caution should be exerted, given the existing comorbidity in advanced a ges, before attributing B-12 deficiency to a condition which may be the exp ression of another concomitant condition.