Who is most at risk
for Pernicious Anaemia?

Pernicious Anaemia (PA) is an autoimmune condition where your immune system attacks either intrinsic factor (IF) and/or the cells in your stomach that produce IF, the protein essential for absorbing vitamin B12 from food. This leads to B12 deficiency, which can cause a wide range of symptoms—hematologic, neurological, and systemic—often developing gradually over years. It is underdiagnosed, partly because symptoms overlap with many other conditions and standard tests have limitations.

Age: It Can Affect Anyone, But Risk Increases Over Time

While Pernicious Anaemia is classically associated with older adults (often due to age-related gastric atrophy), it can occur at any age.

Patient surveys and clinical data confirm diagnoses across the lifespan. For example, the Pernicious Anaemia Society survey (historically reporting peaks in the 41–50 age group) aligns with broader observations that younger patients more often have classic autoimmune PA (anti-IF antibodies or absent IF production), while older patients frequently have overlapping atrophic changes.
PA diagnosis age
PA in children: It is rare but documented, including congenital/juvenile forms due to intrinsic factor deficiency or autoimmune mechanisms. Cases present as early as infancy (e.g., our youngest reported member was around 18 months), with symptoms like failure to thrive, irritability, pallor, and developmental concerns. Pediatric cases often link to other autoimmune conditions or genetic factors.

Genetics and Family History

There is a strong family link in Pernicious Anaemia. Always mention any family history of PA, autoimmune thyroid disease, type 1 diabetes, vitiligo, or similar conditions to your doctor—especially if your B12 levels are “normal” but symptoms persist. This raises clinical suspicion and can justify further testing (e.g., anti-IF antibodies, gastrin levels, or endoscopy). First-degree relatives (parents, siblings) of someone with PA have roughly 3–4 times higher risk; sibling risk can be even higher. In patient surveys, 30–46% report at least one affected family member (parents, siblings, grandparents, etc.).

family with PA
Family member with PA

Gender: More Common in Women, But Affects Both

There is a female predominance (often cited around 1.5:1 or higher depending on the population), which aligns with many autoimmune diseases. However, men are also affected, and some datasets show more balanced ratios. Patient support groups often skew heavily female, likely because women are more proactive about sharing health experiences and seeking community.
If you’re male and have symptoms plus risk factors (family history, other autoimmunity), advocate just as strongly—PA is not “a women’s disease.”

gender PA

Associated Conditions and Other Risk Factors

Because diagnosis can be delayed, many patients first receive labels like depression, anxiety, IBS, chronic fatigue/ME, menopause-related issues, or iron deficiency. If these don’t fully explain your symptoms, consider pushing for B12 testing.

  • Other autoimmune diseases: 35–50%+ of PA patients have at least one additional diagnosis (e.g., thyroid disease, type 1 diabetes, vitiligo). Screen for these if not already done.
  • Gastrointestinal factors: Celiac, Crohn’s, gastric surgery/bypass, or pancreatic issues.
  • Medications: Long-term PPIs, metformin, etc., can impair B12 absorption.
  • Diet: Strict vegan or vegetarian without reliable B12 supplementation.
  • Personal or family autoimmune history.

Read more about PA and other conditions here

Ethnicity: Not Limited to Any One Group

PA occurs worldwide and affects people of all ethnic backgrounds. It is more prevalent in those of Northern European (including Scandinavian and Celtic) and African descent than in Asian populations, but no one is exempt. The outdated stereotype of it being a “fair-haired, blue-eyed” condition is simply not accurate.

When to test for B12 deficiency?

The first step in diagnosing Pernicious Anaemia is almost always diagnosing a B12 deficiency (serum B12, plus markers like MMA or homocysteine if borderline).
  • (Macrocytic) anaemia
  • Neurological/neuropsychiatric symptoms: tingling, problems with remembering words, brain fog, sensory loss, dementia, psychosis, paranoia, depression, mood swings, behavioural changes, etc.
  • Symptoms as glossitis, extreme fatigue, loss of appetite, weight loss, see more
  • Diabetes, Auto-immune thyroid disease, Crohn’s disease, MS, pancreatic insufficieny, gastric bypass, coeliac disease
  • Use of medication : metformin, ppi’s, Questran, colchicine
  • Vegan/strict vegetarian diet

Read more about the diagnosis of Pernicious Anaemia.

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