I have some questions about cholesterol readings.
13 years ago (age 40), after getting an initial total cholesterol reading of 305, being quite concerned, I started cutting fats from my diet, which HAD included whole milk, eggs fried in butter, lots of fat in general. Since then I've had 5 full cholesterol screenings. The first one was 3 months after the 305 reading, after a lot of low-fat eating. It was total=162, LDL=102, HDL=44, TG=78, which gives a ratio of 3.7 or a percentage of 27. Of course, this dietary regime was one that I wasn't likely to continue indefinitely.
A few years later, and eating much fast food, my figures were: Total=254, LDL=147, HDL=86, TG=105, which gives a ratio of 2.95 or a percentage of 33.9. At this time the doctor told me my cholesterol was "great" and that I didn't have to worry about what I ate. As he is a cardiologist this certainly surpised me but I was happy to accept it.
Some of the time these past 13 years I have done aerobics and weight training. I am always fairly active. During my very least active spell, "sedentary" by my standards (and also eating poorly by the way), I had a Total=236, LDL=161, HDL=66, TRI=48 which gives a ratio of 3.57 or a percentage of 27.9
My last test, last summer, had the following results Total=288, LDL=191, HDL=88, TG=48 which gives a ratio of 3.27 or a percentage of 30.5. The doctor suggested that I take medication to lower my cholesterol based on the high LDL reading. I have been hesitant to do so. I currently do step aerobics and weight work at home and since that last screening have been eating reasonably well.
So, my questions:
Is LDL ever actually measured or is it always calculated? Wouldn't a high Total chol reading usually give you a high LDL as well, even after having subtracted a high HDL reading, and especially after subtracting one fifth of an already low TG reading?
Are there upper limits of possible Total, HDL, and LDL? When my total was 305 might my HDL have been higher still than 88?
What are the current guidelines for determining whether a person should take cholesterol lowering medication? Is it the LDL reading? The HDL reading? The ratio of Total to HDL?
Thanks.