Association between serum lipids and apolipoprotein E phenotype is influenced by diet in a population-based sample of free-living children and young adults: the Cardiovascular Risk in Young Finns Study

Apolipoprotein E (apoE) is a genetic determinant of coronary heart disease and lipid levels in several populations. We studied whether the association of apoE alleles with serum lipids varies with diet in a population of free-living young Finns. One thousand twelve subjects, aged 9-24 years, were studied as a part of the Cardiovascular Risk in Young Finns Study in 1986. Serum lipid concentrations and apoE phenotypes were determined, and the composition of the diet was assessed by the 48-h recall method. The subjects were divided into three groups according to the intake of dietary saturated fatty acids (SAFA, g/1000 kcal) and cholesterol (mg/1000 kcal). Group one (high SAFA-cholesterol group) was formed from subjects belonging to the highest tertiles of both cholesterol and SAFA intakes (n = 175); group two (middle SAFA-cholesterol group) consisted of subjects belonging to the middle respective tertiles (n = 119); and group three (low SAFA-cholesterol group) consisted of subjects belonging to the lowest respective tertiles (n = 192). The statistical significance of the association of serum total cholesterol and low density lipoprotein (LDL) concentration with apoE phenotype increased from the low SAFA-cholesterol group (P = 0.024 for total cholesterol and P = 0.015 for LDL-cholesterol, respectively) to the high SAFA-cholesterol group (P = 0.0022 and P = 0.00073, respectively). The middle SAFA-cholesterol group fell between these two groups. The average serum cholesterol lowering effect of the epsilon 2 allele in the low, middle, and high SAFA-cholesterol groups was; -0.22 mmol/l, -0.33 mmol/l, and -0.52 mmol/l, respectively, while the epsilon 4 allele raised these levels by +0.27, +0.36, +0.52 mmol/l, respectively. The results for serum LDL-cholesterol were parallel to those of serum total cholesterol. The average effect of the epsilon 2 allele on serum triglyceride was to raise its level in the subject belonging to low SAFA-cholesterol group only (P = 0.0008)