Vitamin B12 deficiency in the elderly.
D000368:Aged; D006801:Humans; D008314:Malonates / Q000652:urine*; D008764:Methylmalonic Acid / Q000652:urine*; D014806:Vitamin B 12 Deficiency / Q000175:diagnosis*
D008314:Malonates; D008764:Methylmalonic Acid