There's a specific combination of lipids/lipoproteins that confers especially high risk for heart disease. That combination is:
Low HDL--generally less than 50 mg/dl
Small LDL--especially if 50% or more of total LDL
Lipoprotein(a)--an aggressive risk factor by itself
This combination is a virtual guarantee for heart disease, often at a young age. It's not clear whether each risk factor exerts its own brand of undesirable effect, or whether the combined presence of each cause some adverse interaction.
For instance, lipoprotein(a), or Lp(a), by itself is the most aggressive risk factor known (that nobody's heard about--there's no blockbuster revenue-generating drug for it). Each Lp(a) molecule is a combination of an LDL cholesterol molecule with a specific genetically-determined protein, apoprotein(a). If the LDL component of Lp(a) is small, then the combination of Lp(a) with small LDL is somehow much worse, kind of like the two neighborhood kids who are naughty on their own, but really bad when they're together.
Interestingly, the evil trio responds as a whole to many of the same corrective treatments:
Niacin --increases HDL, reduces small LDL, and reduces Lp(a)
Elimination of wheat, cornstarch, and sugars --Best for reducing small LDL; less potent for Lp(a) reduction.
High-fat intake --Like niacin, effective for all three.
High-dose fish oil --Higher doses of EPA + DHA north of 3000 mg per day also can positively affect all three, especially Lp(a).
If you have this combination, it ought to be taken very seriously. Don't let anybody tell you that it is uncorrectable--just because there may be no big revenue-generating drug to treat it on TV does not mean that there aren't effective treatments for it. In fact, some of our biggest successes in reducing heart scan scores have had this precise combination.