People with color blindness and bladder cancer may not see blood in their urine, which may mean they have worse outcomes, according to a recent study published in the journal Nature Health.
Currently, there is no regular screening test for bladder cancer. It is usually diagnosed when a person notices symptoms and tells their doctor. The first symptom in most people is painless blood in the urine.
But what if a person cannot see blood in their urine? This can happen in people with color vision deficiency, also known as color blindness. The majority of color vision deficiencies impair how well a person can see the color red.
In this study, researchers used data from TriNetX, a large database with health records from over 275 million patients. The researchers compared people who had both bladder cancer and color blindness with people who had bladder cancer but normal color vision. They looked at how long patients lived and their risk of dying over 20 years. They also made sure the groups were similar in age and health conditions.
The study found that people with both bladder cancer and color blindness were less likely to survive than those without color blindness. They also had a 52% higher chance of dying over 20 years.
Read more about bladder cancer signs and symptoms
The researchers also looked at people with colorectal cancer, which causes blood in stool. Even though people with color blindness might also have trouble seeing blood in their stool, this mattered less because colorectal cancer has regular screening tests, such as colonoscopies or stool tests, starting at age 45.
The researchers said this study raises an important idea: doctors should be more alert for bladder cancer in patients with color vision deficiency. Additionally, these findings should “prompt further investigation into whether screening for bladder cancer should be introduced for high-risk individuals with color vision deficiency,” they said.
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