Methodological issues in nutrition surveillance: the CDC experience.

Nutrition surveillance systems serve to provide state- and locality-specific data that are useful for the management of public health nutrition programs. Current systems, such as the Pediatric and Pregnancy Nutrition Surveillance Systems coordinated by the Centers for Disease Control (CDC), collect program-based data focused on nutrition problems in infants, children, and pregnant women. These systems provide highly useful information, but also present significant methodological challenges relating to representativeness, quality control, and indicator sensitivity/specificity. As the importance of nutritional risk factors for chronic disease is increasingly recognized, the concept of nutrition surveillance must be expanded beyond maternal and child nutrition to include nutrition-related behaviors and risk factors in adolescents and adults. The Behavioral Risk Factor Surveillance System (BRFSS), coordinated by CDC, collects telephone survey data that include information on nutrition-related issues such as overweight, weight-loss practices, and cholesterol screening. In addition, a school-based surveillance system is being established by CDC in coordination with state education agencies to assess adolescent health behaviors, including nutrition. The operation of these nutrition surveillance systems presents significant methodological issues that must be considered in interpreting and using the data for public health purposes.