Pernicious anemia—a condition where your body can’t absorb vitamin B12—increases your risk of developing tuberculosis by about 13.5%, according to a 2026 genetic study published in Current Molecular Medicine. Gram Research analysis of this bidirectional Mendelian Randomization study found this causal relationship in genetic data from thousands of people, though iron deficiency anemia and aplastic anemia showed no connection to TB risk.
According to Gram Research analysis, a new genetic study found that pernicious anemia—a condition where your body can’t absorb vitamin B12 properly—may increase your risk of developing tuberculosis (TB). Researchers used advanced genetic data from thousands of people to trace whether anemia actually causes TB, rather than just appearing together. They discovered a clear link between pernicious anemia and TB, but found no connection between two other common types of anemia and TB. This finding suggests doctors should watch TB patients more closely if they have pernicious anemia, and it opens new doors for understanding how vitamin B12 deficiency might weaken the immune system against TB infection.
Key Statistics
A 2026 genetic study of anemia and tuberculosis found that pernicious anemia increases TB risk by 13.5% (OR = 1.135, 95% CI = 1.035-1.244, p = 0.007), making it a significant genetic risk factor for tuberculosis.
According to Gram Research analysis of a 2026 bidirectional Mendelian Randomization study, iron deficiency anemia and aplastic anemia showed no causal relationship with tuberculosis, suggesting that vitamin B12 deficiency specifically—not anemia in general—drives TB risk.
A 2026 genetic analysis found no evidence that tuberculosis causes pernicious anemia, suggesting the relationship is one-directional: anemia increases TB risk, not the reverse.
The Quick Take
- What they studied: Whether different types of anemia (blood disorders) actually cause tuberculosis, or if they just happen to occur together in some people
- Who participated: Researchers analyzed genetic information from large international studies involving thousands of people with anemia and tuberculosis, but didn’t recruit new study participants themselves
- Key finding: Pernicious anemia—caused by vitamin B12 deficiency—increases TB risk by about 13.5%, but iron deficiency anemia and aplastic anemia showed no causal link to TB
- What it means for you: If you have pernicious anemia, doctors may want to screen you for TB symptoms. This is especially important in countries where TB is more common. However, this is genetic research, not a guarantee that anemia will cause TB in any individual person
The Research Details
This study used a special genetic research method called Mendelian Randomization, which is like a detective tool for finding true cause-and-effect relationships. Instead of following people over time (which can be confusing because many things happen at once), researchers looked at genetic variations that naturally occur in human DNA. These genetic variations act like natural experiments—some people inherit genes that make them more likely to develop anemia, while others don’t. By studying these genetic differences across thousands of people, scientists can figure out whether anemia actually causes TB, or if they’re just connected by chance.
The researchers gathered genetic data from large international studies (called GWAS studies) that had already collected information on people with pernicious anemia, iron deficiency anemia, aplastic anemia, and tuberculosis. They then used mathematical methods to trace whether genetic risk factors for anemia also increased TB risk. They tested the connection in both directions—does anemia cause TB, or does TB cause anemia?—to make sure they understood the relationship correctly.
To make sure their findings were solid, the researchers used multiple statistical methods and ran sensitivity tests. This is like checking your math several different ways to make sure you got the right answer. They also looked for signs that their results might be biased or influenced by hidden factors.
This approach is important because regular studies can be misleading. When two diseases appear together, it’s hard to know which one causes the other, or if a third factor causes both. Genetic studies avoid this confusion because genes are inherited randomly and don’t change based on whether you get sick. This makes them much better at proving cause-and-effect relationships.
This study has several strengths: it used data from large, well-designed international studies; it tested results multiple ways to confirm findings; and it checked for potential biases. However, the study is based on genetic data, which means it shows what could happen based on genetics, not what definitely will happen to any individual person. The researchers didn’t directly measure vitamin B12 levels or TB symptoms in individual patients, so some details about how the connection works remain unclear.
What the Results Show
The study found clear evidence that pernicious anemia increases the risk of developing tuberculosis. Specifically, people with genetic risk factors for pernicious anemia had about 13.5% higher odds of having TB. This relationship was statistically significant, meaning it’s unlikely to be due to chance alone.
In contrast, the two other types of anemia studied—iron deficiency anemia and aplastic anemia—showed no causal connection to TB. This is an important distinction because it suggests that not all types of anemia affect TB risk equally. The specific problem in pernicious anemia appears to be the inability to absorb vitamin B12, rather than anemia itself.
When researchers tested the opposite direction—whether TB causes anemia—they found no evidence for this relationship. This suggests the connection is one-way: pernicious anemia may increase TB risk, but TB doesn’t appear to cause pernicious anemia. This helps confirm that anemia is a risk factor for TB, not a consequence of it.
The study’s sensitivity analyses (extra tests to check if results hold up) confirmed that the findings were robust and not due to hidden biases or statistical errors. The researchers found no significant heterogeneity, meaning the results were consistent across different analytical methods. This consistency strengthens confidence in the main finding about pernicious anemia and TB.
Previous studies had suggested a link between anemia and TB, but couldn’t prove which caused which. This is the first genetic study to specifically investigate whether anemia causes TB. The finding that only pernicious anemia shows a causal relationship is new and suggests that vitamin B12 deficiency, rather than low iron or other causes of anemia, is the key factor. This narrows down what doctors and researchers should focus on when studying anemia and TB together.
This study has several important limitations. First, it’s based on genetic data, which shows associations in populations but can’t predict what will happen to individual people. Second, the study doesn’t explain exactly how vitamin B12 deficiency increases TB risk—it only shows that it does. Third, the genetic data comes from people of European ancestry primarily, so results may not apply equally to all populations. Finally, the study can’t account for other factors like nutrition, living conditions, or immune system strength that might influence both anemia and TB.
The Bottom Line
Healthcare providers should consider screening patients with pernicious anemia for tuberculosis, especially in regions where TB is common (moderate confidence). Patients with pernicious anemia should ensure they receive adequate vitamin B12 treatment and maintain regular check-ups (moderate confidence). People at risk for pernicious anemia should be aware of TB symptoms like persistent cough, fever, and night sweats (moderate confidence). However, having pernicious anemia doesn’t mean you will definitely develop TB—it just increases the statistical risk.
This research is most relevant for doctors treating patients with pernicious anemia, public health officials in countries with high TB rates, and researchers studying TB prevention. People with pernicious anemia should be aware of this connection. However, people with iron deficiency anemia or aplastic anemia don’t need to worry about increased TB risk based on this research. The general public should understand this is genetic research showing population-level risks, not individual predictions.
If you have pernicious anemia and receive proper vitamin B12 treatment, you may reduce your TB risk over time, though this study doesn’t specify how long this takes. TB screening should happen promptly if symptoms develop. The benefits of treating pernicious anemia extend beyond TB prevention, so treatment should begin immediately if diagnosed.
Frequently Asked Questions
Does anemia increase your risk of getting tuberculosis?
Pernicious anemia—caused by vitamin B12 deficiency—increases TB risk by about 13.5% according to genetic research. However, other types of anemia like iron deficiency anemia don’t show this connection, suggesting B12 deficiency specifically affects TB susceptibility.
What type of anemia is linked to tuberculosis?
Pernicious anemia, which develops when your body can’t absorb vitamin B12 properly, shows a causal link to tuberculosis. This is the only anemia type in the study with a proven genetic connection to TB.
If I have pernicious anemia, will I definitely get tuberculosis?
No. Having pernicious anemia increases your statistical risk of TB by about 13.5%, but most people with pernicious anemia won’t develop TB. This is a population-level finding, not a guarantee for individuals. Proper B12 treatment and TB screening are important preventive steps.
How does vitamin B12 deficiency affect tuberculosis risk?
The exact mechanism isn’t fully understood yet, but vitamin B12 is crucial for immune system function. B12 deficiency may weaken your body’s ability to fight TB infection. This study proves the connection exists but doesn’t explain all the details of how it works.
Should I get tested for tuberculosis if I have pernicious anemia?
Yes, especially if you live in an area with higher TB rates or have TB symptoms like persistent cough, fever, or night sweats. This genetic research suggests doctors should screen pernicious anemia patients for TB as a precaution.
Want to Apply This Research?
- Users with pernicious anemia should track vitamin B12 levels quarterly and log any TB-related symptoms (persistent cough lasting more than 3 weeks, fever, night sweats, weight loss) to share with their doctor
- Set reminders for regular B12 supplementation or injections as prescribed, schedule annual TB screening if you have pernicious anemia, and maintain a symptom log within the app to discuss with healthcare providers
- Create a quarterly health check-in that includes B12 level review, TB symptom screening, and medication adherence tracking. Flag any new respiratory symptoms for immediate medical attention
This research identifies a genetic association between pernicious anemia and tuberculosis risk based on population-level data. It does not diagnose, treat, or predict TB in any individual person. Having pernicious anemia does not mean you will develop tuberculosis. If you have pernicious anemia, consult your healthcare provider about appropriate TB screening and vitamin B12 treatment. If you experience symptoms of TB (persistent cough, fever, night sweats, weight loss), seek immediate medical attention. This article is for educational purposes and should not replace professional medical advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.