Low Density Lipoprotein Cholesterol/Apolipoprotein B-100 Ratio: Interaction of Family History of Premature Atherosclerotic Coronary Artery Disease With Race and Gender in 7 to 11 Year Olds

Abstract

In adults, a low density lipoprotein cholesterol (LDL-C)/apolipoprotein B-100 (ApoB) ratio is an indicator of ApoB-enriched small dense LDL, which is associated with premature coronary artery disease (CAD). Since this LDL subclass may be inherited, we investigated whether a low LDL-C/ApoB ratio was associated with a positive family history of premature CAD in young children. Subjects were 66 children aged 7 to 11 years who were recruited through a school-based family history survey, flyers, and hospital newspaper advertisements. They were divided according to family history and assessed for fatness, blood pressure, lipids, lipoproteins, and apoproteins. Family history interacted with gender such that girls with a positive family history had a lower LDL-C/ApoB ratio than girls with a negative family history, while the opposite was true in boys; ie, family history-positive boys had a higher ratio than family history-negative boys. The association of a low ratio with a positive family history was seen most clearly in white girls. Family history-positive whites had higher ApoB than family history-negative whites, whereas the pattern was reversed in the blacks. The LDL-C/ApoB ratio and ApoB were not related to other CAD risk factors such as fatness, blood pressure, or other lipids and lipoproteins. In young children, a low LDL-C/ApoB ratio and high ApoB levels were associated with a positive family history of CAD only in the white girls, suggesting that this group is at increased risk of genetically mediated CAD.