Adherence to Recess Guidelines in the United States Using Nationally Representative Data: Implications for Future Surveillance Efforts.

Background: National adherence to the recess recommendations of the Centers for Disease Control and Prevention (CDC) has not been comprehensively studied in the United States.

Methods: Data from 6 nationally representative data sets over the last decade (Classification of Laws Associated with School Students, Early Childhood Longitudinal Study, National Health and Nutrition Examination Survey, National Youth Fitness Survey, School Health Policies and Practices Survey, and the School Nutrition and Meal Cost Study) provided estimates for adherence to CDC recess guidelines.

Results: While approximately 65-80% of elementary school-children receive the recommended 20+ minutes of daily recess according to parent-, principal-, and school-report, adherence declines by sixth grade, and little information is available for middle/high school students.

Biomarkers in phase I-II chemoprevention trials: lessons from the NCI experience.

Early phase clinical trials are an essential component of chemopreventive drug development to identify signals of drug efficacy that can subsequently be explored definitively in phase III trials. Whereas phase I trials focus on safety and identification of optimal dose and schedule for cancer prevention, phase II trials focus on intermediate endpoints that are variably related to cancer development. The United States National Cancer Institute supports a programme devoted to early phase cancer prevention clinical trials.