1) To determine whether greater levels (type, frequency, duration, intensity) of physical activity are associated with higher levels of recommended cancer screening compliance in the PLCO trial.
Hypothesis: Individuals who are more physically active will also be more likely to be compliant with cancer screening recommendations.

2) To determine whether physical activity variables, including total monthly activity frequency, activity type (ratio of aerobic, strength-training, and lifestyle activities performed monthly), and intensity/duration (measured as the total minutes per month spent in intensity categories: strenuous, moderate, light or as the ratio of time per month spent in each category) affect the risk of all cancer incidence in the PLCO trial.

Main Hypothesis: Individuals who are more physically active will be less likely to develop cancer when compared to those who are less physically active.

• Sub-hypothesis (frequency): Individuals who participate in more frequent activity will have a significantly greater overall cancer risk reduction than individuals who have less frequent activity
• Sub-hypothesis (activity type): Individuals who have greater variety in their ratio of activity types will have a greater overall cancer risk reduction than individuals who concentrate activity on a single type.
• Sub-hypothesis (intensity/duration frequency): Individuals who have a higher number of total minutes spent at strenuous and moderate levels of activity will have a greater overall cancer risk reduction than individuals who have low total minutes spent at strenuous and moderate levels of intensity.
• Sub-hypothesis (intensity/duration ratio): Individuals who have a higher proportion of total activity minutes spent at strenuous intensities will have a greater overall cancer risk reduction than individuals who spend the majority of active time in light intensity activities.

2a) To evaluate whether current physical activity recommendations are most likely to reduce cancer risk.

Main Hypothesis: Current guidelines (150 minutes per week of moderate to vigorous exercise) are most likely insufficient to maximize overall cancer risk reduction benefits.

• Subhypothesis: Increasing physical activity intensity/duration (evaluated in quintiles for this population) will result in a greater overall cancer risk reduction.

3) To determine whether physical activity variables, including total monthly activity frequency, activity type (ratio of aerobic, strength-training, and lifestyle activities performed monthly), and intensity/duration (total minutes per month spent in intensity categories: strenuous, moderate, light AND the ratio of time per month spent in each category) affect the risk of specific cancers in the PLCO trial.

Main Hypothesis: Risk reduction benefits from physical activity variables will differ by cancer type.
Sub-hypothesis: Measured variables will differ in effect on specific cancer risk reductions.

4) Examine whether physical activity type, frequency, intensity, and duration are differently associated with self reported family history of cancer. Cancer incidence will be compared between average, moderate and high risk subgroups of family history of prostate, colon, breast and ovarian cancers.

Lisa Gren, PhD: Department of Family & Preventive Medicine, University of Utah
Saundra Buys, MD: Huntsman Cancer Institute, University of Utah
Jessica Greenwood, MD MSPH: Department of Family & Preventive Medicine, University of Utah
Janet Shaw, PhD: Department of Exercise & Sports Science, University of Utah
Yelena Wu, PhD: Department of Family & Preventive Medicine, University of Utah
Mia Hashibe, PhD: Department of Family & Preventive Medicine, University of Utah