Efficacy and safety of lowering dietary intake of fat and cholesterol in children with elevated low-density lipoprotein cholesterol. The Dietary Intervention Study in Children (DISC). The Writing Group for the DISC Collaborative Research Group

Abstract

Objective: To assess the efficacy and safety of lowering dietary intake of total fat, saturated fat, and cholesterol to decrease low-density lipoprotein cholesterol (LDL-C) levels in children.

Design: Six-center randomized controlled clinical trial.

Participants: Prepubertal boys (n = 362) and girls (n = 301) aged 8 to 10 years with LDL-C levels greater than or equal to the 80th and less than the 98th percentiles for age and sex were randomized into an intervention group (n = 334) and a usual care group (n = 329).

Intervention: Behavioral intervention to promote adherence to a diet providing 28% of energy from total fat, less than 8% from saturated fat, up to 9% from polyunsaturated fat, and less than 75 mg/4200 kJ (1000 kcal) per day of cholesterol (not to exceed 150 mg/d).

Main outcome measures: The primary efficacy measure was the mean LDL-C level at 3 years. Primary safety measures were mean height and serum ferritin levels at 3 years. Secondary efficacy outcomes were mean LDL-C levels at 1 year and mean total cholesterol levels at 1 and 3 years. Secondary safety outcomes included red blood cell folate values; serum zinc, retinol, and albumin levels; serum high-density lipoprotein cholesterol (HDL-C) values, LDL-C:HDL-C ratio, and total triglyceride levels; sexual maturation; and psychosocial health.

Results: At 3 years, dietary total fat, saturated fat, and cholesterol levels decreased significantly in the intervention group compared with the usual care group (all P < .001). Levels of LDL-C decreased in the intervention and usual care groups by 0.40 mmol/L (15.4 mg/dL) and 0.31 mmol/L (11.9 mg/dL), respectively. Adjusting for baseline level and sex and imputting values for missing data, the mean difference between the groups was -0.08 mmol/L (-3.23 mg/dL) (95% confidence interval [CI], -0.15 to -0.01 mmol/L [-5.6 to -0.5 mg/dL]), which was significant (P = .02). There were no significant differences between the groups in adjusted mean height or serum ferritin levels (P > .05) or other safety outcomes.

Conclusions: The dietary intervention achieved modest lowering of LDL-C levels over 3 years while maintaining adequate growth, iron stores, nutritional adequacy, and psychological well-being during the critical growth period of adolescence.