Feb. 1 (UPI) -- Overweight and obese people who lose weight may reduce their risk for developing polyps that are often a precursor for colon cancer, a study published Tuesday by the journal JNCI Cancer Spectrum found.
Compared to adults who had a stable weight, those who lost at least 1 pound every five years had a 46% lower likelihood of having colorectal adenoma, a benign growth or polyp in the colon or rectum that could lead to colorectal cancer, the data showed.
Conversely, weight gain of about 7 pounds or more over five years during adulthood was associated with a 30% higher risk for adenoma.
For men, this weight gain increased their adenoma risk by 41%, compared with 9% for women, according to the researchers.
"Weight loss in adulthood, particularly for overweight and obese adults, may help reduce adenoma risk," study co-author Kathryn Hughes Barry told UPI in an email.
"If someone could lower the chances of developing this precancerous growth, then this could help prevent colorectal cancer," said Barry, an assistant professor of cancer epidemiology at University of Maryland School of Medicine in Baltimore.
Colorectal cancer is the third most common type of cancer and the third leading cause of cancer death among both men and women in the United States, according to the American Cancer Society.
Obesity, which affects more than 40% of adults nationally, based on Centers for Disease Control and Prevention estimates, is a known risk factor for colorectal adenoma and colorectal cancer.
Those who are overweight or obese are more likely to develop insulin resistance, which raises blood sugar levels, according to Barry.
Insulin is a hormone that helps transport sugar, or glucose, into cells in the body.
In response to insulin resistance, the body may produce more of the hormone, which can increase cell growth and reduce the chance of cell death, changes that are linked with higher risk for developing cancer, Barry said.
The findings of this study are based on 17,629 adults ages 55 to 74 in the United States who self-reported their weight data, of whom about 1,000 people developed colorectal adenoma in the study follow-up period.
They suggest the importance of healthy weight maintenance throughout adulthood in reducing colorectal adenoma and, thus, colorectal cancer risk, the researchers said.
"We recommend healthy weight maintenance and avoidance of weight gain throughout adulthood to help lower an individual's chance of developing colorectal adenoma, which may in turn reduce the risk of developing colorectal cancer," Barry said.
"Additionally, adults who are overweight or obese may benefit from losing weight in reducing their risk of adenoma, among other potential health benefits," she said.