To the Editor.
—The article by Dr Bostom and colleagues1 reaffirms the importance of an elevated lipoprotein(a) [Lp(a)] level as a cardiac risk factor. We have postulated previously, based on our analysis of published works,2 that a pathological interaction exists between increased Lp(a) levels and elevated low-density lipoprotein (LDL) cholesterol levels, which is confirmed by our own experience.3 Furthermore, by lowering LDL cholesterol levels alone, the adverse effects of the interaction of these 2 particles is greatly diminished.3Bostom and colleagues did not observe such an interaction. The most likely explanation is that LDL cholesterol levels in their study were low (mean, 3.5 mmol/L [135 mg/dL]) relative to the mean LDL cholesterol levels in most studies previously published.2 We observed that, in the presence of such low LDL cholesterol levels, increased Lp(a) levels had only a small or negligible impact on disease outcome.2 In
Maher VMG, Brown BG. Elevated Lipoprotein(a) and Premature Coronary Heart Disease. JAMA. 1997;277(3):209. doi:10.1001/jama.1997.03540270035011