Re-analysis of the DISC Study: Advanced Statistical Approaches to Understanding Dietary Interventions in Pediatric Cardiovascular Health

Background: The Dietary Intervention Study in Children (DISC) showed that a cholesterol-lowering dietary intervention can improve pediatric cardiovascular risk factors. Building on advances in longitudinal modeling, we re-analyzed DISC data to (1) reassess intervention effects using linear and spline mixed-effects models, (2) evaluate treatment effects within key subgroups, and (3) examine the impact of compliance on percent calories from fats. Methods: We conducted a secondary analysis of the randomized DISC trial, comparing a dietary intervention group with a usual care group. Linear mixed-effects and B-spline mixed-effects models characterized trajectories of LDL-cholesterol (LDL-C) and nutrient intake over time. We evaluated subgroup differences by sex and parental education and assessed compliance using session attendance and adherence to dietary goals for saturated fat, cholesterol, and total fat. Results: Compared with usual care, the intervention group showed a significant initial reduction in LDL-C and sustained decreases in total and saturated fat intake. B-spline models identified non-linear trends in LDL-C and dietary fat over follow-up. Higher attendance at intervention sessions was associated with reduced fat intake, with this effect less pronounced among girls. The intervention group also showed higher adherence to dietary goals, and higher parental education was related to better attendance. Conclusion: This reanalysis indicates that a family-based dietary intervention initiated in childhood can produce meaningful reductions in LDL-C and sustained improvements in dietary fat intake. The findings highlight the importance of adherence, parental involvement, and targeted support for specific subgroups in promoting long-term cardiovascular health in pediatric populations. Trial registration: NCT00000459.