OBJECTIVE:

To determine the prevalence of undiagnosed vitamin B12 deficiency among residential aged care facility residents in southern Tasmania, Australia, and to identify associated risk factors.

DESIGN AND SETTING:

Cross-sectional study of residents from five southern Tasmanian residential aged care facilities.

PARTICIPANTS:

Two hundred and fifty-nine residents without a prior diagnosis of vitamin B12 deficiency or recorded serum B12 level within the past 6 months were approached to have their serum B12 level tested. One hundred and sixty (61%) residents consented and their doctors were contacted for further consent. A total of 130 (50%) residents completed the study.

MEASUREMENTS:

Clinical and demographic characteristics, and serum B12 level.

RESULTS:

Of the 130 residents tested, 18 residents (14%) were considered vitamin B12 deficient (serum level <150 pmol/L), 47 (36%) were equivocal (150 pmol/L to 250 pmol/L) and 65 (50%) had normal serum B12 levels (>250 pmol/L). There was a weak negative correlation between age and serum B12 level in those residents not taking a multivitamin (n=120, r=-0.19, p<0.05). The use of a multivitamin or antipsychotic drug were associated with altered mean serum B12 levels (+137 pmol/L, p<0.001 and -70 pmol/L, p<0.001 respectively).

CONCLUSION:

As vitamin B12 deficiency can manifest in a range of symptoms that are frequently misdiagnosed, the finding of undetected deficiency in 14% of residents is a cause for concern. Oral multivitamin supplementation may help prevent deficiency, and potentially treat existing deficiencies in older institutionalised people.