Design and statistical analysis for the Pathways study

We report the design, rationale, and statistical procedures used in Pathway s, a randomized, school-based intervention for the primary prevention of ob esity in American Indian children. The intervention, which is now being imp lemented in 7 American Indian communities around thr country, includes a he alth-promotion curriculum, a physical education program, a school meal prog ram, and a family involvement component. Forty-one schools serving American Indian children were randomly assigned to be either intervention or contro l groups. The intervention will begin in the third grade and continue throu gh the end of the fifth grade. Efficacy of intervention will be assessed by differences in mean percentage body fat, calculated by a prediction equati on, between intervention and control schools at the end of the fifth grade. Power computations indicate that the study has power to detect a mean diff erence of 2.8% in body fat. Data analysis will, use intention-to-treat conc epts and the mixed linear model. The study will be completed in 2000. Am J Clin Nutr 1999; 69(suppl):760S-3S.