Objectives: The dietary assessment methods used in the Dietary Intervention Study in Children (DISC) are described and the rationale, validity, and/or general usefulness of each are discussed.
Design: DISC is the first multicenter, randomized, clinical trial to study the feasibility and long-term efficacy, safety, and acceptability of a fat-moderately diet in 8- to 10-year-old prepubescent children with moderately elevated plasma low-density lipoprotein cholesterol (LDL-C) levels. Final data collection for the original study (DISC I) occurred December 1, 1993; continued intervention and follow-up (DISC II) will extend beyond 1997.
Setting: Six clinical centers across the country participate in DISC.
Subjects: Preadolescent boys and girls with fasting LDL-C levels between the 80th and 98th age-specific and sex-specific percentiles established by the Lipid Research Clinics were eligible for the study. The feasibility phase included 140 children who were then enveloped into the full-scale trial. Baseline dietary data for 652 randomized children in the full-scale trial and 6-month results for the feasibility cohort are reported.
Interventions: Dietary assessment involved several elements: (a) determining eligibility based on consumption of more than 30% of energy from total fat, (b) monitoring adherence to and adequacy of the intervention diet, (c) evaluating acceptability of the diet in the intervention group, and (d) determining appropriate foods for the intervention diet. Methods are described for each purpose.
Main outcome measures: LDL-C differences between the two groups and differences in total and saturated fat intakes as calculated from three 24-hour recalls were the primary outcome measures. Six-month dietary differences in the feasibility group are reported.
Statistical methods: Baseline group means and 6-month differences in dietary intake are reported for the full-scale trial and feasibility study, respectively.
Results: Baseline mean intake from three dietary recalls for the intervention (n = 328) and control (n = 324) groups, respectively, were as follows: energy = 1,759 kcal and 1,728 kcal; total energy from fat = 33.3% and 34.0%; total energy from saturated fat = 12.5% and 12.7%; and total dietary cholesterol = 209 mg and 195 mg. After 6 months of intervention, percentage of energy from total fat and saturated fat was reduced by 5.1% (P = .004) and 2.9% (P < .001), respectively, in this feasibility subset (n = 73) of the intervention group. Essentially no change in these parameters occurred in the control group (n = 67), which demonstrates a measurable difference in reporting between groups.
Applications/conclusions: Results illustrate the feasibility of implementing a variety of dietary assessment methods among preadolescent children without relying primarily on parental reports.