Monday, 26 August 2013

False dichotomies: serum cholesterol level vs all-cause mortality. Cause or effect?

Here are some plots from the MRFIT study.

Although the relative risk (RR) for coronary heart disease (CHD) and cardiovascular disease (CVD) mortalities increase with serum total cholesterol (TC) level, all-cause mortality follows a U-curve.

According to Low Serum Cholesterol and Mortality: Which Is the Cause and Which Is the Effect?, certain illnesses that increase mortality lower TC levels. This is the Iribarren hypothesis.

According to Cholesterol and all-cause mortality in elderly people from the Honolulu Heart Program: a cohort study, TC that's low and is still low 20 years later results in a 64% increase in the RR for mortality relative to TC that's intermediate and is still intermediate 20 years later.

Table 4 Relative risk for mortality based on change in cholesterol between examinations three and four
Is low TC level the cause of, or the effect of fatal illnesses? I think that it's both. Cholesterol is an important substance, as a severe lack of it is bad news, as per Smith–Lemli–Opitz syndrome. If certain illnesses result in a depletion of cholesterol and cholesterol synthesis is too low, there's insufficient cholesterol to allow recovery.

Interestingly, TC that's low but is intermediate 20 years later results in a 30% increase in the RR for mortality, whereas TC that's low but is high 20 years later results in a 5% increase in the RR for mortality.

P.S. There's a false dichotomy for vitamin D level vs illness. Ditto for carbohydrates vs calories.


ProudDaddy said...

Given that statins don't help us over 70 folks without heart disease, what would the MRFIT curves look like for men over 70?

Nigel Kinbrum said...

I can't quantify it, but the left end of the all-cause mortality curve rises with increasing age, which shifts the minimum to the right.

There are some more studies (including Schatz et al) on TC vs mortality in

Alex Cray said...

Alex Cray
Revita Shampoo or conditioner is an revolutionary,
normal shampoo or conditioner that's created specifically to aid folks who suffer from men and women along with would like to truly do something positive about the idea with no adding additional substances within their body.

Eshal Shah said...

It is a good blog and nice to know about this blog and thanks for sharing here with us
college thesis writing help

MacSmiley said...

Plant Positive discusses SLOS in this video. There's more to this defect than cholesterol levels. In fact, someone with SLOS can have normal cholesterol. Check out the info on an enzyme called 7-dehydrocholesterol reductase.

Nigel Kinbrum said...

Bookmarked! Going out to jam session now.