Updated 22 March 2017

Too much sitting tied to higher risk of colon polyps in men

'Active couch potatoes' who do get some exercise just as vulnerable, study suggests.

Men who are more sedentary face a higher risk of recurring colon polyps, according to a new study, even if they break up their downtime with bouts of recreational activities such as walking, jogging or golf.

This suggests that extended inactivity is itself a risk factor for noncancerous colon polyps (benign tumours), which can give rise to colorectal cancer, the researchers said.

Known as "colorectal adenomas," these polyps typically can be removed after being identified during a colorectal cancer screening, such as a colonoscopy.

The recurrence of such polyps, however, seems to be greater among men (but not women) who are relatively less active.

The researchers looked at activity levels among more than 1 700 men and women and found that the more leisurely the men's lifestyle, the greater their risk for precancerous polyps.


Men who spent 11 or more hours a day in seated endeavours -- such as writing or reading -- were 45% more likely to develop polyps than those who spent less than seven hours a day engaged in sedentary behaviour.

Dr Christine Sardo Molmenti of the department of epidemiology at the Columbia University Mailman School of Public Health, said: "Sedentary behaviour is emerging as a risk factor for poor health.

"Even among those who fulfill daily recommendations for physical activity, lengthy periods of sedentary behaviour have been associated with early morbidity and mortality, leading to the 'active couch potato' paradigm," Sardo Molmenti said.

What did the study find

Although the study found an association between sedentary behaviour and increased risk of colon polyps in men, it did not prove a cause-and-effect relationship.

The authors said no protective link had been established between being more active and having a lower risk for colorectal cancer.

"Given the substantial increase in the risk of [colon polyp] recurrence we observed, we believe it would be beneficial to see 'reduce prolonged sitting time' added to the list of public-health recommendations currently in place for health promotion and disease prevention," Sardo Molmenti said.

More information

For more on colorectal cancer, visit the US National Cancer Institute.


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