Recorded presentation

Charles DiSogra, DrPH, Tobacco-Related Disease Research Program, University of California--Office of the President, 300 Lakeside Drive, 6th floor, Oakland, CA 94612, 510-987-9875, charles.disogra@ucop.edu, Mark Hudes, PhD, Department of Nutritional Sciences, University of California, Berkeley, 1317 Washington Ave, Albany, CA 94706, and Melissa Gatchell, Center for Health Policy Research, University of California, Los Angeles, 10911 Weyburn Ave., Suite 300, Los Angeles, CA 90024.

Population-based surveys designed to track dietary intake over time may not always be able to collect data during the exact same months each year the survey is fielded. The question arises whether or not there is a seasonal influence on the survey estimates that may obscure the true underlying trends, if any, across multiple years. This is the situation with the bi-annual California Dietary Practices Survey (CDPS) that has tracked fruit and vegetable intake since 1989. A separate calibration study was initiated in November 2000 to examine if seasonality exists for fruit and vegetable intake in the California population. This is also examined for White, African American and Latino groups and their corresponding low-income segments. ANOVA results will be presented from 8,543 telephone interviews collected from twenty-four independent monthly samples using CDPS protocols and methods. Monthly variation in total consumption and for fruit and vegetables separately will be shown for all groups. Despite apparently wide variation, especially for selected race/ethnic groups, even with large sample sizes, it will be shown that no obvious “seasons” could be detected. Findings for low-income Latinos will demonstrate analytical limitations in studies of this design. Issues related to the California food supply, economic factors and individual food choice behavior are discussed.

Learning Objectives: Participants will be able to

• recognize caveats in designing and implementing studies to detect seasonal fluctuation in dietary intake;
• understand the analytical limits with these type of data;
• asses the necessity of incorporating seasonal adjustments in surveys tracking dietary intake over time.

Keywords: Survey, Food and Nutrition

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.

Recorded presentation