To the Editor.
—We read with much interest the recent review article by Dr Slyper1 summarizing the literature on small, dense low-density lipoprotein (LDL) as a risk factor for coronary heart disease (CHD). We wholeheartedly concur with his conclusion that "[u]nraveling the connection between dense LDL and atherogenesis will have important consequences for the treatment and prevention of coronary artery disease." However, his statement that "genetics has a limited influence on LDL phenotype" is incorrect. For example, recent results from a large study of female twins by Austin et al2 demonstrated that one third to one half of the variation in LDL size is attributable to genetic influences, a statistically significant result. Findings from the National Heart, Lung, and Blood Institute3 male twin study are remarkably similar and fail to reach significance only because a statistical test with low power to detect genetic influences was used. Further
Austin MA, Krauss RM. LDL Density and Atherosclerosis. JAMA. 1995;273(2):115. doi:10.1001/jama.1995.03520260035025