Overuse of Antibiotics Linked to Precancerous Colon Polyps

Taking antibiotics for an extended period of time in early and middle adulthood may increase your risk of developing precancerous growths called polyps in your colon, a large study suggests. [1]

The research, published in the journal Gutadds to a growing collection of evidence that the type and diversity of gut microbes may play a significant role in the development of cancer.

Many people develop diarrhea when they take antibiotics. This is because the drug kills some of the normal gut bacteria, thus allowing an overgrowth of abnormal bacteria to dominate.

Read: Gut Health is Directly Linked to Chronic Illness, Overall Health

For the study, researchers in the U.S. tracked the health of over 120,000 nurses between the ages of 30 and 55 who took part in the Nurses Health Study that launched in 1976. The team found that between 2004 and 2010, 1,194 nurses were diagnosed with abnormal growths in the colon and rectum.

Participants who had taken antibiotics for two months or more between the ages of 20 and 39 were 36% more likely to be diagnosed with a polyp, called an adenoma, compared with those who hadn’t taken a prolonged course of antibiotics during their 20s and 30s.

Women who had taken antibiotics for two months or more during their 40’s or 50’s were 69% more likely to be diagnosed with a polyp.

Similarly, women who took antibiotics for 15 days or more between ages 20 and 39, and between ages 40 and 59, were 73% more likely to be diagnosed with an adenoma.

Source: Your Health Blog

Read: Why Probiotics are Essential if You are Taking Antibiotics

Associate Professor Graham Newstead, the head of the colorectal unit at the Prince of Wales private hospital and director of Bowel Cancer Australia, said:

“It does seem to indicate that people who have too many antibiotics might be at more risk of [sic] getting polyps than people who have less of them.

And, remembering that not all polyps turn to cancer but the cancer comes from the polyps. If you have more polyps or tendency to get polyps then maybe you are slightly more at risk of getting cancer.” [1]

The researchers wrote in the report:

“Antibiotics fundamentally alter the gut microbiome, by curbing the diversity and number of bacteria, and reducing the resistance to hostile bugs.

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.

The findings if confirmed by other studies, suggest the potential need to limit the use of antibiotics and sources of inflammation that may drive tumor formation.” [2]

Other Risk Factors for Colorectal Cancer

Occurrence of polyps in the gastrointestinal tract.

Dr. Andrew Chan, an associate professor of medicine at Harvard Medical School, said the study doesn’t prove that antibiotics cause polyps, only that there is a connection. [3]

And while the study looked at women, Chan said the study likely also holds true for men.

“More research needs to be done to understand the interaction between alterations in one’s gut bacteria and future risk of colorectal cancer.” [3]

There are several known risk factors for bowel cancer besides polyps, including:

  • Being overweight or obese
  • Not getting enough physical activity
  • Diets that are high in red meat and processed meats
  • Cooking meats at very high temperatures (frying, boiling, or grilling)
  • Smoking
  • Heavy alcohol use
  • Being age 50 or older
  • A personal history of colorectal cancer
  • A personal history of inflammatory bowel disease
  • A family history of colorectal cancer or polyps
  • Certain inherited syndromes
  • Being African-American or a Jew of Eastern European descent
  • Having type 2 diabetes [4]

There is even some research that suggests that working a night shift regularly may increase your risk for colorectal cancer, possibly due to changes in levels of melatonin.


[1] The Guardian

[2] BBC News

[3] WebMD

[4] American Cancer Society

Your Health Blog

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Study: Cigarettes are Behind a Shocking 30% of Cancer Deaths

It may be common knowledge that smoking cigarettes leads to a host of diseases and early death, but did you know that 30% of all cancer deaths are smoking-related? This is according to a study published in JAMA Internal Medicine. [1]

Smoking is the biggest preventable cause of death from cancer and other diseases, yet 40 million people continue to puff away on cigarettes, according to U.S. researchers from the American Cancer Society (ACS).

The ACS calculated the percentage of cancer deaths among Americans 35 years of age and older due to cigarette smoking in 2014, state by state.

The percentage of smoking-related deaths for men ranged geographically, from about 22% in Utah to nearly 40% in Arkansas. The percentage was at least 30% in every state but Utah.

The percentage was considerably lower for women – at least 20% in all states except Utah, California, and Hawaii. Women in Utah were found to have the fewest smoking-related deaths (11%), and Kentucky women had the most (29%).

Although men are more likely to smoke than women, researchers believe their chromosomes may play a role in their higher cancer death rate. Recent studies have shown that smoking reduces the number of Y chromosomes in blood cells, which help contain tumors.

However, in states like South Dakota, Montana, and Arkansas, researchers found there were more female than male smokers.

In the South, nearly 40% of cancer deaths are linked to smoking. That’s likely because of the region’s lenient laws concerning smoking policies and relatively flimsy tobacco control programs, not to mention the cheaper cost of cigarettes. [1], [2]

The authors of the study warn that their estimates are probably low. In the study, they only considered 12 types of cancer, and the researchers did not include other types of tobacco use, such as hookah, cigars, or e-cigarettes. The team also did not include second-hand smoke in their analysis. [1]

The researchers wrote:

“Increasing tobacco control funding, implementing innovative new strategies, and strengthening tobacco control policies and programs, federally and in all states and localities, might further increase smoking cessation, decrease initiation.” [2]

Read: Quit Smoking Tips that Go Beyond the Patch, Pill, or Phone Support

The types of cancer covered by the study include:

  • bladder
  • cervix
  • colon
  • rectum
  • esophagus
  • kidney
  • ureter
  • larynx
  • leukemia
  • liver
  • oropharynx
  • pancreas
  • stomach
  • trachea
  • bronchus [2]

The states with the highest estimated proportion of smoking-related cancer deaths in men were:

  • Arkansas
  • Tennessee
  • Louisiana
  • Kentucky
  • West Virginia [3]


[1] Time

[2] Tech Times

[3] CBS News

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