Physical Activity and Its Components in Relation to Plasma Inflammatory Markers of Cancer Risk Among Chinese Adults

In the past decade, China has experienced fundamental decreases in the populations' physical activity levels, due to increasingly sedentary occupations and lifestyles. However, the transition to a Western lifestyle has not reached the entire Chinese population. The resulting wide range of between-person variation in physical activity provides an unparalleled opportunity for physical activity studies. Although physical activity measurement techniques have evolved considerably over the past years, the main obstacle in quantifying physical activity is the complexity of precisely measuring its individual components, particularly low to moderate-intensity activities.

Recently, investigators at Vanderbilt University, the Shanghai Cancer Institute, and the DCEG initiated two prospective population-based cohort studies: the Shanghai Women's Cohort and the Shanghai Men's Cohort. The aim of these studies is to prospectively examine the relations of diet, lifestyle, occupational, and environmental risk factors, as well as genetic variation, to cancer incidence among 75,000 women and 73,000 men, aged 40 to 70 years old, and residing in Shanghai, China. We propose to conduct a study among 600 women and men participating in these two cohort studies. The specific objectives of the current study are to develop a comprehensive physical activity questionnaire and to assess the validity and reliability of this instrument in the Shanghai cohorts using objective measures of physical activity/physical fitness: activity monitors, and the Modified Canadian Aerobic Fitness Test. In addition, we intend to evaluate whether different types and parameters of physical activity are associated with circulating levels of specific inflammatory markers that have been linked to cancer risk. The specific markers are C-reactive protein (CRP), interleukin 6 (IL-6), and soluble tumor necrosis factor alpha (TNF-a). The impact of potentially confounding variables of the association between physical activity and inflammatory markers, such as recent exercise, use of anti-inflammatory drugs, and current or recent infections, will be carefully accounted for in the analysis.