Vitamin B12 deficiency in the elderly and screening
What it found
Vitamin B12 deficiency is common in older people and often missed, but there is no reliable test to screen everyone.
The authors support more testing and supplements in the elderly.
What they found
Studies in people
How common
Among elderly people, vitamin B12 deficiency ranges from 5% to 40% depending on how it is defined. Using a serum level below 150 pmol/L, it is 5% to 15%, but with higher cut-offs or extra tests it rises to 40.5%.
Institutionalised vs free-living
Institutionalised elderly with multiple illnesses are more prone to deficiency than those living independently. In one unpublished study of 2096 residents over 65, 34.9% had low serum vitamin B12, while only 6.6% of free-living elderly over 70 did.
Causes in elderly
The most common cause is food-cobalamin malabsorption, where vitamin B12 cannot be released from food, often due to atrophic gastritis. Pernicious anaemia and long-term use of certain drugs also contribute.
Symptoms and effects
Symptoms are often vague and non-specific, like fatigue or confusion, but can include anaemia and nerve damage. Deficiency is linked to higher risk of cognitive impairment and depression.
Treatment
Oral vitamin B12 can be as effective as injections, even for pernicious anaemia. Suggested doses are 1 mg daily for a month, then 125 to 250 µg daily for dietary insufficiency or 1 mg daily for pernicious anaemia.
Other findings
Diagnosis challenges
There is no gold standard test. Serum vitamin B12 cut-offs are debated, and extra tests like homocysteine and methylmalonic acid are more sensitive but can give false results and are not standardised.
What the authors conclude
“Overall, we are in support of screening for vitamin B12 deficiency in the elderly.”
Also in their conclusions
- They support screening for vitamin B12 deficiency in the elderly.
- They say that high prevalence, higher risk in the elderly, and safe treatment options warrant more liberal testing and vitamin supplementation.
- They note that accurate diagnosis remains controversial and no reliable screening tool is available.
How it was done
The authors wanted to review whether screening for vitamin B12 deficiency in the elderly is worthwhile, given how common and serious it can be.
They reviewed studies on how common vitamin B12 deficiency is in older people, how it is diagnosed, its causes, effects, and treatment. They also included their own unpublished study of 2096 institutionalised elderly residents.
What it can’t tell you
- This is a review, not a new study, so it cannot prove cause and effect.
- The findings are based on other studies with different definitions and methods, so results may not apply to everyone.
- It cannot show whether screening all elderly people would improve health outcomes.
Who paid
- Authors work at
- Caritas Medical Centre, Hong Kong
The paper
- Title
- Vitamin B12 deficiency in the elderly: is it worth screening?
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Wong CW (2015). Vitamin B12 deficiency in the elderly: is it worth screening?. Hong Kong medical journal = Xianggang yi xue za zhi. doi:10.12809/hkmj144383Free full textPubMed 25756278DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error