April 5 (UPI) -- Researchers from Harvard Medical School and Massachusetts General Hospital found a link between long-term antibiotic use and the development of bowel polyps.
The study analyzed data from 16,642 nurses in the long-term U.S. Nurses' Health Study and found nurses ages 20 to 39 and 40 to 59 who had taken antibiotics for two months or more were at increased risk of developing bowel polyps known as adenomas, a precursor for the majority of colorectal cancers. All study participants had undergone at least one colonoscopy.
Researchers documented 1,195 cases of adenoma and found that women who used antibiotics for two months or more between the ages of 20 to 39 were more likely to be diagnosed with adenomas in later life. The study also found women who took antibiotics for two months or more between 40 and 59 were even more likely to be diagnosed with adenoma decades after.
"Antibiotics fundamentally alter the gut microbiome, by curbing the diversity and number of bacteria, and reducing the resistance to hostile bugs," study authors stated. "This might all have a crucial role in the development of bowel cancer, added to which the bugs that require antibiotics may induce inflammation, which is a known risk for the development of bowel cancer."
Several factors can increase a person's risk of bowel cancer including family history, diet, alcohol use, smoking and obesity.
Researchers say additional studies on the impact of antibiotic exposure with gut microbial composition and function are needed.
The study was published in the journal Gut.