Colorblindness might be an even greater disadvantage than people typically consider. Recent research suggests that individuals with colorblindness could struggle to detect certain cancers in a timely manner.
Researchers from Stanford University investigated the medical histories of those with colorblindness and a cancer diagnosis. They discovered that colorblind individuals faced a higher likelihood of poor outcomes, particularly with bladder cancer. The study indicated that these individuals often fail to notice blood in their urine—a crucial early warning sign for the disease.
“I hope this research helps raise awareness, not just for patients with colorblindness, but also for healthcare professionals who treat them,” said Ehsan Rahimy, senior study author and adjunct clinical associate professor of ophthalmology, as noted in a recent Stanford Report.
A color disadvantage
Colorblindness—also known as color vision deficiency—is fairly common, especially among men. Approximately 8% of men are estimated to experience some level of colorblindness, compared to about 0.5% of women.
Genetic mutations often cause colorblindness, which manifests in various forms depending on how a person’s cone cells function differently. Normally, these cones detect blue, red, and green light, sending corresponding signals to the brain. The interpretation of other hues comes from a blending of these signals. However, many colorblind individuals struggle with seeing both red and green.
In some cases, the condition is so mild that individuals may go years without realizing they have it. Yet, some small studies have suggested that those with colorblindness may experience more severe challenges when diagnosed with bladder or colorectal cancer. Since these cancers can lead to blood appearing in urine or stool (often without accompanying pain) before more obvious symptoms arise, it’s been proposed that colorblind people might simply overlook these early signs.
To explore this further, researchers analyzed a comprehensive database of electronic health records. They focused on 136 colorblind individuals diagnosed with bladder cancer and 187 with colorectal cancer, comparing them with similar non-colorblind patients.
The findings revealed that colorblind individuals with bladder cancer had a shorter life expectancy than their non-colorblind peers. Over a period of 20 years, they faced a 52% increased risk of mortality. Interestingly, no significant difference in survival rates was noted between colorblind and non-colorblind individuals diagnosed with colorectal cancer.
The researchers are still trying to understand why this trend was exclusive to bladder cancer. They mentioned that colorectal cancer presents other early symptoms—like chronic diarrhea or constipation—that might be more apparent. Regular screenings for colorectal cancer are often recommended starting at age 45, which could help individuals with colorblindness notice any issues sooner than those without.
What should this mean for colorblind people?
While the researchers emphasize that their findings don’t definitively prove a causal relationship between colorblindness and poorer bladder cancer outcomes, they indicate that more awareness and research into this perception gap are essential. They’re not advocating for immediate changes to medical advice but rather suggesting that clinicians consider this potential discrepancy.
“This study raises important questions about how we diagnose bladder cancer in those with color vision deficiency and whether specific screenings should be developed for high-risk individuals,” they concluded in their paper, recently published in Nature Health.
