abnormally low hdl

Posted By Jodi  on March 25, 1999 at 11:15:39:







At age 52, in general good health (nonsmoker, exercising twice weekly, at a normal weight, normal blood pressure and taking estrogen, good nutrition,very low alcohol intake)  I find that my LDL cholesterol has risen over the last five years from 200 to 245.  But worse, my HDL level has sunk, inexplicably, from 35 to 19. My physician suggested a strictly low fat diet plus niacin for 90 days: result, slightly negative change. So now I'm taking Pravacal.  However, I understand that, while it can dramatically reduce LDL levels, it will not likely affect HDL.
My questions are 1) what would cause such a precipitous decline in HDL levels over a five year period and 2) is there anything that has been known to increase HDL and 3) how seriously at risk for heart attack/stroke am I?
-Jodi