BACKGROUND
In response to the epidemic of childhood obesity, there is growing attention to health policies which address obesogenic environments through increased physical activity and healthy eating. In the United States, much of the authority for public health policy lies at the state level - both through the legislative and regulatory actions taken by the state government and also in how the state constitution imparts authority for local governments. To date, there has been little systematic examination of state policy efforts. To better understand policy-related influences on physical activity, a four-phase framework was recently proposed by Schmid and colleagues focusing on: 1) identification of relevant policies, 2) determinants of establishing policy, 3) development and implementation of policy, and 4) examination of policy outcomes.

OBJECTIVES
This study addresses the first two phases of the policy research framework. Our specific objectives were to 1) identify and describe patterns of state-level childhood obesity prevention legislation introduced and adopted from 2003-2005 and 2) explore bill-level and state-level factors that predict bill enactment.

METHODS
A legislative database was created by Health Policy Tracking Service (HPTS) to systematically identify legislation related to physical activity, nutrition, and obesity prevention, introduced from January 1, 2003 through December 31, 2005 in all 50 states. HPTS used standardized search criteria for 24 community- and school-related topic areas (e.g., walking/biking paths, safe routes to school, school nutrition/vending standards).

The final legislative database included 717 bills and 134 resolutions specifically relevant to childhood obesity prevention. Descriptive analyses examined patterns in the introduction and adoption of legislation by topic area, time, and geography. Among the 717 bills, a two-level hierarchical logistic regression model was constructed to identify bill (level-1) and state (level-2) characteristics associated with bill enactment.

RESULTS
Of the 851 bills and resolutions introduced between 2003 and 2005, 17% of bills and 53% of resolutions were adopted. The topic areas with the most introduced legislation were school nutrition/vending standards (n=238), physical education (n=191), and studies/councils/task forces (n=110). Community-related topic areas of walking/biking paths (37%), farmer’s markets (36%), and statewide initiatives (30%) had the highest proportion of bills adopted, followed by model school policies (29%) and safe routes to school (28%). The amount of legislation introduced and adopted increased between 2003 and 2005. Some regional geographic patterns in the introduction of legislation were observed, however there was no statistical association between the amount of legislation and obesity prevalence.

Multilevel modeling indicated that bill-level characteristics explained more variation in bill enactment than state-level characteristics. Bill-level factors associated with a higher or lower likelihood of bill enactment were observed within the following three categories: legislative process (>1 vs. 1 sponsor, adjusted odds ratio [OR]=1.9; introduced in the senate vs. house, OR=1.9), bill structure (budget bill vs. not, OR=58.0; new vs. amended legislation, OR=0.53), and bill content (safe routes to school, OR=4.2; walking/biking paths, OR=3.5; model school policies, OR=3.4; statewide initiatives/studies/task forces, OR=2.3). State-level factors associated with greater bill enactment included political (2-year vs. 1-year legislative session, OR=1.9; democratic partisan control vs. split party, OR=2.0) and sociodemographic (percent of adolescents not in high school (correlated with poverty indicators), OR=1.4) variables. Economic and industry variables (e.g., per capita expenditures on population health, agricultural employment, campaign contributions by food and activity industries) were not related to bill enactment.

CONCLUSIONS
This study marks the first empirical attempt to systematically identify patterns, trends, and determinants of state-level policy aimed at preventing childhood obesity across all 50 states. Legislation related to active living concepts (i.e., safe routes to school and walking/biking paths) represented about 12% of introduced bills and 24% of adopted bills and were more likely to be adopted than bills in other topic areas (33% vs. 15%). While resolutions were not of key importance for active living legislation (<5% of total), they likely represent a first, capacity-building step among state legislators (e.g., increased consciousness) that may lead to future bills. Expanded tracking and surveillance (including standardized identification and cataloging) of introduced and adopted legislation will enhance the ability to track progress and conduct more sophisticated policy research.

Public health and health policy practitioners can use information on the patterns and predictors of policy enactment to assess progress toward health objectives, identify effective policy approaches, and support advocacy efforts. Currently, there is a limited evidence base describing the impact of policy as an intervention to increase physical activity and prevent obesity. Future policy research should expand upon this study and address additional phases of the policy framework related to determinants, implementation, and effectiveness of obesity prevention legislation.