• Development of a comprehensive, reliable physical activity questionnaire
  
• Validation of the physical activity questionnaire using the accelerometer as an objective measure of physical activity
  
• Correlation of different types and parameters of physical activity with plasma inflammatory biomarkers of cancer risk
  

OBJECTIVES:

• Develop a comprehensive physical activity questionnaire that includes standardized questions about all types of physical activity (e.g., recreational, household, occupational, and transportation-related), as well as parameters of physical activity (e.g., frequency, intensity, and duration in hours per week).
• Assess the validity and reliability of this comprehensive physical activity questionnaire using an accelerometer to objectively measure physical activity.
• Determine whether different types and parameters of physical activity are associated with circulating levels of specific inflammatory biomarkers that have been linked to cancer risk (i.e., C-reactive protein, interleukin 6, and soluble tumor necrosis factor alpha).

OUTLINE: This is a prospective study.

Participants complete a self-administered physical activity questionnaire at baseline to measure their level of physical activity. Participants complete additional activity questionnaires during 30-35 minute interviews conducted at the beginning of the study and at approximately 12 months. Physical activity levels are assessed every 3 months during study using a participant-reported physical activity diary and an activity monitor that is worn at the waist to record participants' physical activity patterns over a 7-day period. Participants also complete a 7-day recall of their physical activities during this period.

Blood and urine samples are collected periodically during study to evaluate levels of nutrients and certain proteins, including specific plasma inflammatory markers that have been linked to cancer risk (i.e., C-reactive protein, interleukin 6, and soluble tumor necrosis factor alpha). The samples are stored for future studies related to nutrition and physical activity, as well as possible research on gene variation and its relationship to health, nutrition, exercise, or disease.