Among adults aged 50 and older, having iron-deficiency anaemia is associated with a 9.7% chance of having colorectal cancer, which is higher than the risk linked to most other symptoms, so it should prompt further testing even if no other signs are present.

We analyzed the available evidence and found that among adults over 50, iron-deficiency anaemia is linked to a 9.7% chance of having colorectal cancer [1]. This level of association is higher than what is seen with most other symptoms, suggesting it may be an important signal to investigate further, even when no other warning signs are present. The evidence we’ve reviewed so far supports this connection, with no studies contradicting it. What we’ve found so far indicates that iron-deficiency anaemia in older adults doesn’t mean cancer is certain, but it does raise the likelihood enough to warrant additional testing. The 9.7% figure represents the chance that someone with this type of anaemia also has colorectal cancer — meaning about 1 in 10 people in this group may need further evaluation. This doesn’t mean anaemia causes cancer, or that all cases of anaemia are due to cancer, but it does point to a pattern worth paying attention to in clinical practice. Our current analysis shows this association is consistently reported across the evidence we’ve reviewed. While we don’t know why this link exists, the data suggest that for adults over 50, unexplained iron-deficiency anaemia should not be ignored. It’s not a diagnosis, but it’s a red flag that may lead to earlier detection. If you’re over 50 and have been diagnosed with iron-deficiency anaemia without a clear cause like heavy periods or diet, it’s worth discussing with your doctor whether further screening for colorectal cancer is appropriate.