People with overweight and obesity who lose weight may reduce their chances of later developing colorectal adenoma, a type of benign growth or polyp in the colon or rectum that could lead to colorectal cancer. The findings reported in the paper, ‘Weight Change and Incident Distal Colorectal Adenoma Risk in the PLCO Cancer Screening Trial’, published in the journal JNCI Cancer Spectrum, underscore the importance of healthy weight maintenance throughout adulthood in preventing colorectal adenoma.
Researchers from the University of Maryland School of Medicine, Baltimore, MD, assessed weight change (including both weight gain and weight loss) over three periods of adulthood in relation to colorectal adenoma using self-reported weight data in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.
The trial enrolled 154,942 men and women in the US aged 55 to 74 from 1993 to 2001 to evaluate the effectiveness of different screening approaches in preventing death from various cancers. For each period, they defined stable weight as greater than −0.5kg to less than or equal to 1kg/5 years, weight loss as less than or equal to −0.5kg/5 years, and weight gain as greater than 1-2, greater than 2-3, or greater than 3kg/5 years.
The investigators found that, compared to stable weight, weight loss in adulthood was associated with a 46% reduced risk for colorectal adenoma. This was particularly true among adults who were initially had overweight or obesity. The investigators also reported that weight gain in adulthood was associated with an increased chance of adenoma, particularly for weight gain greater than 6.6lbs over five years. Findings for weight loss and weight gain appeared stronger among men than women. The researchers believe that the findings suggest the importance of healthy weight maintenance throughout adulthood in preventing colorectal adenoma. Additionally, adults who are overweight or obese may be able to reduce their risk for developing colorectal adenoma by losing weight.
"Our findings suggest that avoiding weight gain in adulthood may help lower someone's chance of developing a pre-cancerous growth called colorectal adenoma, which may in turn reduce the risk of developing colorectal cancer," said the study's senior author, Dr Kathryn Hughes Barry. "Based on our findings, we would not recommend weight loss for all adults. But the results suggest that overweight and obese adults may benefit from weight loss."
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