It affects males and females equally. The most common
form, Adult Onset Pernicious Anemia, affects people after the age of 35 years. Studies suggest that about
1% of the elderly population is affected. Congenital Pernicious Anemia is very rare and has an onset
of age between 4 and 28 months. Juvenile Pernicious Anemia has symptoms similar to the adult-onset
type, seems to occur between the ages of 4 and 20 years. North America and
in Europe among people of Scandinavian, English, or Irish descent has the
higher prevalence. It is extremely rare among Asians. Approximately
1.9% of cases may go undiagnosed. Pernicious anemia shows a 10-fold
increase in patients with multiple myeloma and a 250-fold increase in adults
with immunoglobulin deficiency.