(HealthDay News) — Watching too much television may lower odds of survival after colorectal cancer, new research suggests. The findings were published online December 8 in the Journal of Clinical Oncology.

Hannah Arem, PhD, of the U.S. National Cancer Institute in Rockville, MD, and colleagues analyzed data that had been collected for an earlier study. The initial investigation had included 566,398 men and women between the ages of 50–71, all of whom had completed an initial health and lifestyle questionnaire at some point between 1995–1996. All were asked to indicate the degree to which they had routinely participated in moderate to vigorous “leisure-time activity” on a weekly basis over the past decade. In the new analysis, the researchers honed in on nearly 3,800 participants who went on to be diagnosed with colorectal cancer. On average, the diagnoses had occurred approximately five years following completion of the initial survey.

By stacking pre-diagnosis exercise habits up against cancer survival information, the researchers determined that colorectal cancer patients who had ≥7 hours of weekly leisure activity before their diagnosis showed a 20% lower risk of dying – for any reason – than those who had engaged in no leisure activity whatsoever. And after analyzing a follow-up survey completed between 2004–2005 by 1,759 of the original colorectal cancer patients, the team found that those who engaged in ≥7 hours of weekly leisure activity post-diagnosis faced a 31% lower risk of dying from any cause, regardless of their activity levels before diagnosis.

The study team also found that those patients who routinely watched <2 hours of television per week before diagnosis faced a 22% lower risk of dying from any cause than those who watched ≥5 hours per week. “The take-away message from our study is that both minimizing television viewing, to <2 hours per day, and increasing exercise, to four-plus hours per week, were associated with lower mortality risk among colorectal cancer survivors,” Arem told HealthDay.

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