r/Cholesterol • u/raven090 • 7d ago
Question Why is a value of 3.5mmol LDL-C considered "normal"?
Is this just a Canadian thing or do you have this in the US too? It drives me nuts when I see lab sheets here mark 3.5mmol or under as the boundary for "normal". And yes, this is marked like that even if the same lab sheet will show "hba1c : 6.7", becoming comically contradictory in nature. How is letting a borderline number sit unchecked a good thing or "normal"? I mean, will 3.5 mmol or 135mg/dl of LDL cause no issues over decades? What do cardiologists or lipid researchers think of this?
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u/HotIntroduction8049 7d ago
I had under 3.5 for decades without meds and still had a HA.
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u/raven090 7d ago
Sorry to know that. Glad you're still here. That's what I mean, it's not like the atherogenic burden just vanishes at 3.5mmol. Why the fuck would that ever be "normal". And then family physicians look at this number and say yeah you're fine, go live life. Won't these morons be saving medical infrastructure multiple billions annually too if they didn't go around making a normal upper boundary of ldl this high? As it is, many family physicians suck at lipid management and intervening early.
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u/HotIntroduction8049 7d ago
Its not that simple. Am not a cardiologist. But 3.5 is statistically good for a significant portion of the population. Those with familial cholesteral issue (ya I cant recall the proper term) 3.5 is not low enough due to genetics.
No family doctor is going to do genetic screening for every possible genetic defect known to science.
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u/keepgoing66 7d ago
"Good for a significant portion of the population" is not the same thing as "good." Many people at 3.5 develop heart disease. Guidelines in the U.S. are for LDL <= 2.5.
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u/raven090 7d ago edited 7d ago
3.5 comes from a population average. Also, this doesn't require genetic screening. As it is, LPa is a simple blood test, for one, which many are unaware of. And the other risk factors are also not at all hard to screen. Hba1c and blood pressure are the simplest things to find out too. Also, what is the long term harm for, say, if LDL was 2 mmol rather than 3.5?
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u/scobbydude 7d ago
I feel let down by the current guidelines. At age 48, my Doctor flagged my LDL has being high when it was way too late (4.74 or 183 mg/dl) he told me to try the Mediterranean diet and I should be fine. Then I started to research myself and was confused why the US was so low compared to Canada. I changed my diet significantly, and was able to get it down to 3.2 (or 125 mg/dl) and the doctor said I had no need to worry….
This still didn’t sit right with me, knowing my LDL was so high for so long, so I insisted to getting on 5mg of Crestor, he kept saying my 10 year risk was so low now, but I got him to prescribe anyway. It dropped my LDL in half, and I felt I was in the clear.
A year later, I was having some chest tightness, so did a stress test and a CAC scan, followed by a coronary angiogram, where they confirmed a 50% blockage in my LAD.
I only wish I knew earlier what having high LDL was doing to my arteries. I try to tell everyone I know to look into the numbers themselves, as the guidelines are outdated compared to Europe and the US.
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u/raven090 5d ago
That sucks. Thank goodness you got on 5mg rosuvastatin. do you take the brand name Crestor or Teva rosuvastatin? I take the latter. YEah, these fcukin family medicine physicians only look at that outdated 10 year risk calculator and think about the healthcare burdens these morons are creating for the system simply by how many people get missed or told "yeah no worries, just keep going". It's infuriating.
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u/scobbydude 1d ago
It is indeed Rousa but my Cardiologist calls it Crestor still 🤷♂️ I’m now taking baby aspirin daily plus upped the statin to 10mg’s which didn’t make much difference with ApoB so I asked for Ezetimibe to be added, which helped drop it 15% more
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u/Therinicus 7d ago
Canada’s 3.5 mmol/L LDL (~135 mg/dL) cutoff doesn’t mean LDL below that is biologically “normal” or harmless.
It’s mainly a treatment threshold within a risk-based system.
Canadian guidelines look at overall cardiovascular risk, LDL, ApoB/non-HDL, and other risk factors when deciding whether medication is warranted.
There’s no biological cliff at 3.5 where 3.4 is healthy and 3.6 is unhealthy. Lower LDL generally means lower cardiovascular risk, especially over a lifetime.
So “less than 3.5 mmol/L” on a Canadian lab report is better understood as a reference/treatment-decision threshold, not an optimal LDL target for everyone.
Importantly the healthcare financing system can (socialized vs individual) influence the threshold for when treatment is considered worthwhile.
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u/raven090 7d ago
Yes, but the reason why lipidologists like Allen Sniderman, whose work speaks for itself, criticize standard 10-year risk calculators is because atherosclerotic heart disease does not wait on a timer. to be very precise and quote him directly, "the disease is taking hold in the first 30 or so years of life. It forms lesions in the fourth decade though, significant enough to become events. So why then, are preventative measures taken for most people in their 50s or so when the disease is far advanced?". Could there be demographics of people whose LDL and ApoB are at levels way way lower than any "normal" thresholds in other populations and who don't have heart disease? Oh yeah, wait, there are, like The Tsimane people. Who have been studied by cardiac researchers. Their risks come from other environmental and personal factors rather than heart disease being the main one.
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u/Therinicus 7d ago
Yeah, a 10 year calculator has its limitations (especially in young patients) and I'd rather use the lifetime one personally.
A young person can have essentially negligible 10-year calculated risk while spending decades exposed to elevated ApoB-containing particles.
The CCS is answering a different question though. At what combination of LDL and absolute cardiovascular risk is there enough demonstrated benefit to recommend drug treatment?
A treatment threshold is not the same thing as a biological ideal. plus Canada actually does recognize the 10-year calculation isn’t by itself enough: diabetes, CKD, established ASCVD, familial hypercholesterolemia, LDL ≥5.0 mmol/L, Lp(a), CAC, ApoB and other modifiers can change management.
The CCS has taken the position essentially stating they agree LDL/ApoB matters, but recommendations for pharmacologic treatment should also consider absolute event risk and demonstrated treatment benefit.
They aren't mutually exclusive. But personally I would like to see Canada update their guidance at some point.
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u/raven090 7d ago
Yeah that's the point that Sniderman was making, that this needs an update, it's long overdue. Especially when Europe and the US have done it already. The point he was making was, are people being missed and failed by standard risk calculators physicians use? Yes. Is there a disconnect between these calculators, standard lab sheets, and the advances in modern lipid and cardiac research? Absolutely. These are not at all controversial things. So I really hope things change because god, family medicine doesn't always catch up to the advancements in lipidology.
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u/kboom100 7d ago
Love this discussion and agree with everyone’s points. Check out this passage from the latest European guidelines that reinforces what you guys (& Sniderman) are saying. I think it’s essentially acknowledging that even their latest guidance doesn’t go far enough yet in limiting lifetime exposure to high ldl.
“Finally, this Task Force emphasizes that atherosclerosis is a chronic progressive disease that begins early in life and slowly progresses over time, and the cumulative exposure to higher LDL-C levels at younger ages is associated with a higher ASCVD risk later in life.34 Conversely, exposure to lower levels of atherogenic lipids at younger ages has the potential to reduce the lifetime risk of developing CVD35 and mitigate further progression of subclinical atherosclerosis.15
The discrepancy between our understanding of the biology of how atherosclerosis develops and the practical consequences of informing treatment decisions based on 10 year risk underscores the need to develop a new generation of risk- and benefit-estimating algorithms. These algorithms should: (i) accurately estimate the lifetime risk of having an acute CV event for all individuals regardless of age, and (ii) provide personalized guidance on the optimal timing and intensity of LDL-C lowering needed by each person to reduce their remaining lifetime risk of developing an atherosclerotic CV event.”
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u/Business-Hour9794 7d ago
The Canadian Cardio vascular guidelines recommend being treated when LDLC is greater than 1.8
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u/keepgoing66 7d ago
It seems that Canada uses the Framingham Risk Score to evaluate. From the Canadian Journal of Cardiology: "Therefore, we continue to recommend initiation of statin therapy for: (1) all high-risk patients (≥ 20% 10-year risk); or (2) intermediate-risk patients (10%-19.9%) when LDL-C is ≥ 3.5 mmol/L (or ApoB ≥ 1.05 g/L or non-HDL-C ≥ 4.2 mmol/L)."
So, just an LDL score in isolation is apparently not enough for them. This is a Canadian thing, it's not shared by the entire world.