4 ms·

Can someone tl;dr? Not that the paper is too long, but I think I'd need to go back to university and major in biology or statistics to understand what they disc

by pocw 5y ago

Can someone tl;dr? Not that the paper is too long, but I think I'd need to go back to university and major in biology or statistics to understand what they discovered and more importantly what it might mean.

onlyrealcuzzo 5y ago
When you have TC (total cholesterol) < 200 mg/dL (milligrams per deciliter) - each 1mmol/L (millimoles per liter) reduces mortality. When you have TC > 200 mg/dL - each 1mmol/L increases mortality. The confidence interval was high. > In the age groups of 18–34, 35–44, 45–54, 55–64, 65–74, and 75–99 years, each 1 mmol/L higher TC increased mortality by 14%, 13%, 8%, 7%, 6%, and 3%, respectively (P < 0.001 for each age group), for TC ≥ 200 mg/dL, while the corresponding TC changes decreased mortality by 13%, 27%, 34%, 31%, 20%, and 13%, respectively, in the range < 200 mg/dL (P < 0.001 for each age group). TC had U-curve associations with mortality in each age-sex group. TC levels associated with lowest mortality were 210–249 mg/dL, except for men aged 18–34 years (180–219 mg/dL) and women aged 18–34 years (160–199 mg/dL) and 35–44 years (180–219 mg/dL). The inverse associations for TC < 200 mg/dL were stronger than the positive associations in the upper range.
- twoWhlsGud 5y ago
  Speculation in the discussion section is that while lower TC (below the limits cited above) is correlated with lower cardiac risk, it seems to be correlated with a higher risk of death. So the implication is there's something else bad for your health about being out of the sweet spot they observed in the data.
  - gumby 5y ago
    I remember reading about 20 years ago that low cholesterol was correlated with increased mortality due to increased incidence of suicide.
- stavros 5y ago
  So basically the 170 mg/dL TC limit that my lab shows is very suboptimal, and I should go for 230 instead?
  - jeffbee 5y ago
    170 would be in the lowest quartile for American adults, no? Seems like an unreasonable limit.
    - stavros 5y ago
      I'm in Greece, but it seems fairly unreasonable here as well. Other labs have the limit at 200 (it varies per lab), but 170 seems too low.
      - myle 5y ago
        Greeks tend to have higher "normal" cholesterol levels. In other labs I have seen in Greece, they write as the limit 200. I know of someone with TC around 240 and the doctor didn't prescribe statins. Not a medical advice.
  - sooheon 5y ago
    No. Please don't make health decisions off of incorrect inferences from observational studies. https://news.ycombinator.com/item?id=30893041 https://news.ycombinator.com/item?id=30893041
  - imtringued 5y ago
    Imagine you have container ships named HDL and it is loaded with containers called triglycerides. You don't know how many containers you have. You just know you have this many container ships. Do you have too many containers? Do you have too many ships? That question cannot be answered with just one absolute number. This is why the HDL to triglycerides ratio exists.
SnowHill9902 5y ago
There exists a non-zero total cholesterol (TC) concentration in blood which is correlated with the minimum all-cause mortality in human beings. Meaning: lower cholesterol is not always correlated with lower mortality.
stavros 5y ago
Here's the hazard graph for total cholesterol: https://www.nature.com/articles/s41598-018-38461-y/figures/2 https://www.nature.com/articles/s41598-018-38461-y/figures/2 230 mg/dL is associated with the lowest mortality, and anything below or above that increases mortality.
- sooheon 5y ago
  > increases mortality Implies a causal relationship. In reality, it's much more likely that causality points the other way, and an underlying disease like cancer is causing low cholesterol: https://www.ahajournals.org/doi/10.1161/01.cir.92.9.2396 https://www.ahajournals.org/doi/10.1161/01.cir.92.9.2396
  - stavros 5y ago
    That's interesting, thank you.
- tails4e 5y ago
  Is it correct that 230 mg/dl is 5.6mmol/l? We've always been told that we must keep the number below 5 at all costs for health, but this seems to be as bad as being above 6.3. Am I reading this correctly? If so, current medical advice is way off.
sooheon 5y ago
TLDR: this observational study replicated the known phenomenon that (seemingly paradoxically) low cholesterol is correlated with increased risk of mortality. It's an ongoing debate whether low cholesterol is directly bad for you, or it could itself be a marker of underlying disease like cancer. The authors admit this study is unable to shed further light on that debate due to lack of data on specific cause of death.

by pocw 5y ago

onlyrealcuzzo 5y ago

When you have TC (total cholesterol) < 200 mg/dL (milligrams per deciliter) - each 1mmol/L (millimoles per liter) reduces mortality. When you have TC > 200 mg/dL - each 1mmol/L increases mortality. The confidence interval was high. > In the age groups of 18–34, 35–44, 45–54, 55–64, 65–74, and 75–99 years, each 1 mmol/L higher TC increased mortality by 14%, 13%, 8%, 7%, 6%, and 3%, respectively (P < 0.001 for each age group), for TC ≥ 200 mg/dL, while the corresponding TC changes decreased mortality by 13%, 27%, 34%, 31%, 20%, and 13%, respectively, in the range < 200 mg/dL (P < 0.001 for each age group). TC had U-curve associations with mortality in each age-sex group. TC levels associated with lowest mortality were 210–249 mg/dL, except for men aged 18–34 years (180–219 mg/dL) and women aged 18–34 years (160–199 mg/dL) and 35–44 years (180–219 mg/dL). The inverse associations for TC < 200 mg/dL were stronger than the positive associations in the upper range.

twoWhlsGud 5y ago
Speculation in the discussion section is that while lower TC (below the limits cited above) is correlated with lower cardiac risk, it seems to be correlated with a higher risk of death. So the implication is there's something else bad for your health about being out of the sweet spot they observed in the data.
- gumby 5y ago
  I remember reading about 20 years ago that low cholesterol was correlated with increased mortality due to increased incidence of suicide.
stavros 5y ago
So basically the 170 mg/dL TC limit that my lab shows is very suboptimal, and I should go for 230 instead?
- jeffbee 5y ago
  170 would be in the lowest quartile for American adults, no? Seems like an unreasonable limit.
  - stavros 5y ago
    I'm in Greece, but it seems fairly unreasonable here as well. Other labs have the limit at 200 (it varies per lab), but 170 seems too low.
    - myle 5y ago
      Greeks tend to have higher "normal" cholesterol levels. In other labs I have seen in Greece, they write as the limit 200. I know of someone with TC around 240 and the doctor didn't prescribe statins. Not a medical advice.
- sooheon 5y ago
  No. Please don't make health decisions off of incorrect inferences from observational studies. https://news.ycombinator.com/item?id=30893041 https://news.ycombinator.com/item?id=30893041
- imtringued 5y ago
  Imagine you have container ships named HDL and it is loaded with containers called triglycerides. You don't know how many containers you have. You just know you have this many container ships. Do you have too many containers? Do you have too many ships? That question cannot be answered with just one absolute number. This is why the HDL to triglycerides ratio exists.

SnowHill9902 5y ago

There exists a non-zero total cholesterol (TC) concentration in blood which is correlated with the minimum all-cause mortality in human beings. Meaning: lower cholesterol is not always correlated with lower mortality.

stavros 5y ago

Here's the hazard graph for total cholesterol: https://www.nature.com/articles/s41598-018-38461-y/figures/2 https://www.nature.com/articles/s41598-018-38461-y/figures/2 230 mg/dL is associated with the lowest mortality, and anything below or above that increases mortality.

sooheon 5y ago
> increases mortality Implies a causal relationship. In reality, it's much more likely that causality points the other way, and an underlying disease like cancer is causing low cholesterol: https://www.ahajournals.org/doi/10.1161/01.cir.92.9.2396 https://www.ahajournals.org/doi/10.1161/01.cir.92.9.2396
- stavros 5y ago
  That's interesting, thank you.
tails4e 5y ago
Is it correct that 230 mg/dl is 5.6mmol/l? We've always been told that we must keep the number below 5 at all costs for health, but this seems to be as bad as being above 6.3. Am I reading this correctly? If so, current medical advice is way off.

sooheon 5y ago

TLDR: this observational study replicated the known phenomenon that (seemingly paradoxically) low cholesterol is correlated with increased risk of mortality. It's an ongoing debate whether low cholesterol is directly bad for you, or it could itself be a marker of underlying disease like cancer. The authors admit this study is unable to shed further light on that debate due to lack of data on specific cause of death.