OT: Exercise May Improve Odds Against Prostate Cancer Death

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http://consumer.healthday.com/Article.asp?AID=648499

Quiz: Encouraging information but can anyone spot the main problem with the

study method, copied below?

Karl

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To explore how exercise might further improve the odds of survival, Kenfield

and her colleagues tracked the physical exercise routines of just over 2,700

men who had been diagnosed with prostate cancer after 1990. The assessments

took place every two years.

Activities that were assessed included walking, jogging, running, bicycling,

swimming, rowing, stair-climbing, and playing tennis, squash, racquetball

and/or golf. Weight-lifting and arduous outdoor work were also included in

the analysis, and all activities were given a so-called " metabolic

equivalent task " ranking, or MET value, according to the amount of energy

each required relative to being sedentary.

After giving non-vigorous activities a MET ranking of less than 6 and

vigorous activities a value of 6 and up, the authors determined how many MET

hours per week were expended by each patient based on the nature and pace of

each activity they engaged in.

Ultimately, 548 of the patients died during the study period, one-fifth as a

direct result of their prostate cancer diagnosis. But the research team

found that the more active patients had been, the lower their risk of dying

from prostate cancer itself or any other cause.

The more hours the patients devoted to either vigorous or non-vigorous

exercise routines, the better they fared in terms of survival. For example,

men who tallied as much as nine or more MET hours per week -- equivalent to

jogging, biking, swimming or playing tennis for 90 minutes per week -- had a

33 percent lower risk for dying from any cause and a 35 percent lower risk

for dying from prostate cancer than men who expended less than nine MET

hours per week.

Vigorous activity, however, seemed to confer a stronger survival benefit

than non-vigorous activity. Compared with men who participated in vigorous

exercise (such as biking, tennis, jogging, running, and/or swimming) for

less than one hour per week, those who engaged in three hours or more had a

nearly 50 percent drop in death risk due to any cause and a 61 percent drop

in the risk of dying specifically from prostate cancer. In fact, only

vigorous activity was linked to a drop in prostate cancer death risk, the

study authors noted.