199950 Using relative BMI distributions to explore differences within and between gender, race/ethnic, and education subgroups, United States, 1998-2006

Sunday, November 8, 2009

Brian C. Houle, MPH , Sociology, University of Washington, Seattle, WA
More than one-third of U.S. adults were obese in 2005-2006, including 33.3% of men and 35.3% of women. Overall the body mass index (BMI) distribution has shifted to the right, with a greater increase in the prevalence of those who are extremely obese. However, the processes affecting obesity disparities among groups are not well understood. While the BMI distribution contains a wealth of information, traditional analyses rely on capturing differences in averages between groups. This study uses a novel statistical approach, relative distribution methods, to explore inequalities and disparities in obesity prevalence both between and among gender and race/ ethnic subgroups. The relative distribution is effectively a transformation of two distributions into a single distribution that facilitates comparison. It is the set of percentile ranks that cases from one distribution would have if they were placed in another distribution. Data from 1998-2006 from the National Health and Nutrition Examination Survey (NHANES) are used to compare BMI distributions across time both within and among gender, race/ethnic, and education subgroups. Among men, preliminary results suggest a polarized BMI distribution between race/ethnic minorities compared to Whites. Among women, the BMI distribution is shifted to the right for race/ethnic minorities compared to Whites but distributions are similar in shape. Further analyses will decompose shape and location effects while adjusting for age and education covariates. A greater understanding of these differences can help to identify causal mechanisms explaining disproportionate obesity burden in populations, and to more effectively target health interventions to those at greatest risk.

Learning Objectives:
At the end of the session, participants will be able to: 1. List two different statistical approaches to obesity disparity research and their limitations. 2. Describe similarities and differences in the patterns of BMI distributions within and between gender, race/ethnic, and education subgroups over time. 3. Discuss the benefits of relative distribution techniques for exploratory graphic comparisons.

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: Masters training in sociology and public health
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.