Antibiotics May Be Linked to Colorectal Adenomas

Use of antibiotics in early-to-middle adulthood is associated with the risk of colorectal adenomas later in life, according to a recent study.

Previous research has indicated that by altering the gut microbiome, antibiotics may be linked to an increased risk of colorectal cancer. However, it is unknown whether antibiotics are associated with an increased risk of colorectal adenoma.
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To examine this issue, the researchers conducted an analysis of data from 16,642 women aged 60 years or older enrolled in the Nurses’ Health Study. The women had all reported their antibiotic use between the ages of 20 and 39 years, and again between the ages of 40 and 59 years. Current antibiotic use (over the past 4 years) was also assessed.

Overall, 1195 cases of adenoma were documented. Longer durations of antibiotic use at age 20 to 39 years and 40 to 59 was significantly associated with increased colorectal adenoma risk. The associations were similar between low-risk and high-risk adenomas, although they appeared modestly stronger for proximal adenomas compared with distal adenomas. Recent antibiotic use was not associated with risk of adenoma.

“In this prospective analysis nested in a large cohort of women with well-characterised risk factors for colorectal neoplasia, exposure to antibiotics earlier in life (age 20–39 and 40–59) was significantly associated with an increased risk for colorectal adenoma after age 60,” the researchers concluded.

“Additional studies investigating the impact of antibiotic exposure with gut microbial composition and function, particularly in relation to the mechanisms underlying colorectal carcinogenesis, are warranted.”

—Michael Potts

Reference:

Cao Y, Wu K, Mehta R, et al. Long-term use of antibiotics and risk of colorectal adenoma [published online April 4, 2017]. Gut. http://dx.doi.org/10.1136/gutjnl-2016-313413.