Existing information about the prevalence of pernicious anemia is largely based on older surveys that favored florid manifestations, tended to be retrospective analyses of previously diagnosed disease, and
usually studied homogeneous European populations. The
lack of current data in the United States has, among other
things, hampered discussions of the proposal to increase folate intake by the general population.
To estimate the prevalence of undiagnosed
and untreated pernicious anemia among the elderly.
A prospective survey of cobalamin levels and
anti—intrinsic factor antibody was done in the elderly. Blood
testing was done in 729 people aged 60 years or older and
follow-up assessment with the Schilling test and other tests
was offered when results were abnormal.
Seventeen subjects were found to have pernicious
anemia, usually with only minimal clinical manifestations
of cobalamin deficiency. Although cobalamin deficiency had
been suspected by the physicians of three subjects, they had
been treated inadequately and still had evidence of deficiency.
Excluding these three partially treated subjects from the
analysis, 1.9% of the survey population had unrecognized
and untreated pernicious anemia. The prevalence was 2.7%
in women and 1.4% in men; 4.3% of the black women and
4.0% of the white women had pernicious anemia.
Undiagnosed pernicious anemia is a common finding in the elderly, especially among black and
white women. If these findings can be extrapolated,
almost 800000 elderly people in the United States have
undiagnosed and untreated pernicious anemia, and, thus,
would be at possible risk for masked cobalamin deficiency if exposed to large amounts of folate. This
number does not include those elderly with cobalamin
deficiency caused by other disorders or the still
unknown number of younger people with unrecognized pernicious anemia and other causes of deficiency.(Arch Intern Med. 1996;156:1097-1100)