For more than 30 years, I’ve watched women walk out of their doctor’s office holding a cholesterol report stamped “normal.” I’ve seen the relief settle on their faces because they had eaten the vegetables, walked the miles, shown up for every annual physical, and here was proof it had paid off. Too few doctors told them what that report left out. Even fewer investigated further to detect their more subtle risk. This spring, I found out I was one of those women who needed the deeper dive.
I trained in obstetrics and gynecology, then went deep into women’s cardiovascular health, because the same pattern kept walking into my office: women who did everything right, who were sent home reassured, and who never heard about the two numbers that could change how they should think about their hearts for the rest of their lives. Then they end up with an elevated coronary artery calcium score or CT angiogram, or worse yet, a heart attack, and don’t understand why.
Thirty-five years ago, medical school taught me to read a cholesterol panel from top to bottom: total cholesterol, LDL, HDL, and triglycerides. The method that I learned decades ago is still how most doctors read it today. About 10 years ago, I completed a two-year fellowship in advanced cardiometabolic health, where you learn to look under the hood in a more comprehensive way and order different tests, including the ones that show where a person stands right now and what needs to change. I’ve tracked those numbers in my patients ever since, and in myself, including my own ApoB and Lp(a). Watching closely didn’t make me exempt because menopause still moved one of them.
I thought my heart was great. I’m the doctor who once pricked her finger for a journalist’s camera and narrated the wait for a cheap glucose meter like a drumroll, so sure of the result that I was celebrating before it beeped. I eat the SMASH fish and vegetables, wore a continuous glucose monitor for a decade, and exercise regularly. My LDL cholesterol has never once been flagged: 83 mg/dL in 2024, a little lower through 2025, and 93 mg/dL this year, every result tucked under the 100 mg/dL line that keeps a cardiovascular lab report in the normal range.
However, my ApoB told a different story. It hovered around 80 for two years. Then, within a year of my final period, it rose to 91 mg/dL and crossed the 90 mg/dL line the National Lipid Association uses as a treatment threshold for people at borderline or intermediate risk.[1] My LDL never raised its hand. The particle count did.
What happened to me is what happens to many women at menopause. The Study of Women’s Health Across the Nation (SWAN) followed more than a thousand women through their final period and found that LDL cholesterol and ApoB both jump in the year on either side of it, a shift tied to menopause itself rather than to another birthday.[2] Mine jumped on schedule. Yours might too, and if your doctor checks only LDL, the jump can hide in plain sight.
I’ve been humbled by my labs before. At 44, doing everything right and maybe a little smug about it, I took a biological-age test expecting good news, but I was aging faster than my calender age. Yikes. That moment, 15 years ago, got me to rebuild how I practice medicine and take the long view for female longevity, starting with myself.
This time, with my ApoB drifting upward, my doctor suggested Zetia, the brand name for ezetimibe, a daily pill that keeps your gut from absorbing as much cholesterol, both from food and from the bile your liver recycles, so less of it reaches your blood. It’s often added to a statin or used by people who can’t take one or would rather not. In my next post, I’ll tell you what I decided about his recommendation and why.
Lp(a) is the one I got lucky on. Three tests over two years, and mine has never registered above the bottom of the scale, under 10 nmol/L. It’s one of the good things I inherited — though we all have vulnerabilities in our blueprint from our parents, that wasn’t one of them. I did nothing to earn that, which is why I need Laura to show you the other half of this story.
Laura is a women in my practice, with identifying details changed to protect her anonymity. She is 45. Three years ago, her Lp(a) came back at 54 mg/dL, just over the line where it starts to count as high. It was the kind of result that gets a shrug. This year it came back at 70 mg/dL, a 30% jump.
Her LDL cholesterol had been climbing too, from 121 mg/dL three years ago to 148 mg/dL now, so on paper her heart looked like it was getting worse on two fronts at once.
Then we looked at her ApoB: 86 mg/dL, under the same 90 mg/dL line I had just crossed.[1] So her LDL is 55 points higher than mine, but her ApoB is lower.
Her numbers send mixed messages: her LDL said worry, her ApoB said less than you’d think, and her Lp(a) said watch me please. To make sense of either Laura or me, you need to know what each number measures.
LDL is a particle that carries cholesterol through your blood and can lodge in the wall of an artery. The number on your lab report, LDL cholesterol (LDL-C), measures how much cholesterol those particles are carrying, by weight. It doesn’t tell you how many particles there are.[3]
ApoB, short for apolipoprotein B, is a protein. Every particle that can clog an artery wears exactly one ApoB tag: LDL, its cousin VLDL, and Lp(a). Count the tags and you’ve counted the particles.[3]
Think of your bloodstream as a highway. LDL cholesterol tells you how much cargo is on the road, while ApoB tells you how many trucks are carrying it. Usually the two rise and fall together. Mine didn’t.
Lp(a) is pronounced “L-P-little-a.” It’s an LDL-like particle with an extra protein attached, and you inherit your level from your parents. Your genes set most of it, and diet and exercise barely move it.[3][4]
Higher Lp(a) means higher heart risk, on its own, separate from your other numbers. A level of about 50 mg/dL (125 nmol/L) is considered high and carries roughly 40% more risk of cardiovascular disease. At about 100 mg/dL (250 nmol/L), the risk roughly doubles.[3]
The data in women is strong. Researchers who followed nearly 28,000 healthy women for close to 30 years, in a study published this year, found that the risk of heart attack and other major cardiovascular events began to climb once Lp(a) passed about 30 mg/dL. The women at the very top, above 131 mg/dL, had about 74% more risk than women below the median.[5]
US and European guidelines both recommend that every adult have Lp(a) measured at least once in their lifetime.[3][4]
For most people, Lp(a) stays in the same general range across a lifetime.[3] Within that range, it moves more than most of us were taught. When Johns Hopkins researchers tested more than 600 people twice, about 4 in 10 saw their Lp(a) change by more than 25%, and among those who started in the borderline zone, about a third moved up into the high-risk range on the second test while a fifth moved down.[6]
So a 30% jump sits within what we see. Some of that movement comes from the test itself, since labs measure Lp(a) in different ways, which is why the new US guideline calls for better-standardized assays.[3] Some of it is biology. A separate analysis from the same menopause study tracked women year by year and found that Lp(a) peaked in late perimenopause and early postmenopause, the years when estrogen falls.[7] At 45, Laura is walking into that window.
Either way, her number crossed further into the zone that may signal significant risk and a shift that size deserves a deeper look.
Most of the time, LDL cholesterol and ApoB tell the same story. When they don’t, doctors call it discordance, and it’s common.[1] The people most likely to carry an ApoB that runs high for their LDL are those with metabolic syndrome or high triglycerides.[8] I have neither. My triglycerides are low and my HDL is high, and a national study of US adults found that this mismatch turns up in metabolically healthy people too.[9]
Laura has the opposite mismatch. Her LDL cholesterol is high, and her ApoB is lower than you’d expect. In truck terms, she has a lot of cargo riding in fewer trucks, and fewer particles means fewer chances for one to lodge in an artery wall. I have modest cargo in more trucks than my LDL lets on.
So which number should guide care? When LDL and ApoB disagree, the National Lipid Association concludes that heart risk generally follows ApoB, or non-HDL cholesterol, a related measure.[1] Among people already taking statins, a Copenhagen team found that Laura’s pattern, a high LDL with a low ApoB, wasn’t linked to more heart attacks or deaths, though because those patients were on treatment, the match to Laura isn’t perfect.[10] The same group reported this year that when ApoB and non-HDL cholesterol disagree, either kind of mismatch carries more heart attack risk than having both low, and having both high carries the most.[11]
For Laura, that’s reassuring, and it still leaves work to do. Her risk sits closer to what her ApoB says than what her LDL says, and her ApoB count already includes her Lp(a) particles, since each one wears an ApoB tag too.[3] For me, it means my “normal” LDL was the wrong number to lean on.
ApoB earns its place even when the numbers seem to agree. Among more than 95,000 Danish adults not taking statins, about 1 in 10 carried enough extra ApoB, beyond what their LDL predicted, to raise their heart attack risk by roughly half, in women and in men.[12] The test is precise and well validated, and the National Lipid Association wants it used far more than it is.[1]
Here’s where I want to be precise with you. The new US guideline keeps LDL cholesterol as the main target. It says ApoB can sharpen the picture in selected people, especially women with high triglycerides, diabetes, or the cluster of heart, kidney, and metabolic problems doctors now call cardiovascular-kidney-metabolic syndrome, and in people whose LDL has already reached its goal.[3] For women who aren’t on a cholesterol drug, it calls ApoB reasonable for refining risk and deciding when to start treatment, which is exactly where I sat this spring.[3]
There’s a limit, and you should know it. The evidence for ApoB rests mostly on observational and discordance studies, and the National Lipid Association has asked that future cholesterol-drug trials measure ApoB so we learn how best to treat to it.[1]
Laura’s numbers left one question open: had any of this already started to build up in her arteries? Her coronary artery calcium score, a quick, low-dose CT scan that looks for hardened plaque in the arteries of the heart, came back 0. Short version: CAC=0.
A zero is good news because two large US studies found that people with a high Lp(a) and a calcium score of 0 had about the same 10-year risk as people with a normal Lp(a) and a score of 0, and that risk climbed most when a high Lp(a) showed up alongside a high calcium score.[13]
A calcium score only sees plaque that has already hardened, so softer, younger plaque can sit there unseen. Among people with a score of 0 in the Miami Heart Study, 16% had plaque on a CT angiogram, though fewer than 1% had a significant narrowing.[14] A zero buys time. It can still miss soft plaque.
We didn’t treat her LDL number as the whole story, and we didn’t wave off her Lp(a). We used each number for the job it does best, and we added two more steps.
First, hormones. We started transdermal estradiol at 0.05 mg, with progesterone 100 mg at night. Estrogen lowers Lp(a): across 24 trials, hormone therapy lowered it by about 20% on average, and estrogen by mouth lowered it more than estrogen through the skin.[15] In those trials, the route mattered more than the dose, so we went in knowing her starting plan may not move her Lp(a) much.
Hormone therapy isn’t approved as an Lp(a) treatment, and I don’t prescribe it for that reason alone.
Second, a closer look at her arteries. We’re adding a CT angiogram with AI plaque analysis, which can see the soft plaque a calcium score misses.[14] We use Cleerly. (I’m not paid by the company. I use it because I find it helpful in my patients.)
Plaque comes in two broad kinds. Soft plaque, which doctors call noncalcified plaque, is the younger kind. It's a deposit inside the artery wall made of cholesterol-rich particles (the ApoB trucks that slipped through the wall and got stuck), inflammatory cells, and a fibrous cap on top. It's still active, and it's the kind more likely to rupture and set off the clot behind a heart attack. Calcified plaque is what soft plaque can turn into over time, as the body walls it off with calcium, the way a wound hardens into a scar. It tends to be more stable, and it's the only kind a calcium score can see.
Women and men build plaque differently. On average, women develop plaque later than men (calcium shows up about 10 years later), and at any given age they have less of it, both soft and hard. So a calcium score of zero is much more common in women, especially younger women. Over time the patterns also split. Women’s plaque tends to harden into calcium faster, while men’s tends to keep growing as soft plaque and to develop more of the high-risk features. But less plaque doesn’t mean less danger. In women, each bit of plaque, whether soft or calcified, carries more risk than the same amount does in a man, and high-risk soft plaque predicts heart attacks and other events more strongly in women. Many women with symptoms have plaque that doesn’t narrow the artery enough to show up on a standard stress test, and that plaque still counts.
So Laura’s CAC=0 tells us she has no hardened plaque, but it can’t tell us whether she has soft plaque. In a woman her age, soft plaque is exactly the kind a calcium score would miss. We’re adding a CT angiogram with AI plaque analysis, which uses contrast dye to show the artery walls themselves and can measure the soft plaque a calcium score misses. [1] We use Cleerly. (I’m not paid by the company. I use it because I find it helpful in my patients.)
Her Lp(a) became a reason to be stricter about everything she can change: her LDL, her blood pressure, the habits that feed both. The new US guideline handles a high Lp(a) the same way, by pushing harder on LDL.[3] Stricter doesn’t mean miserable. Calorie restriction may add years to a life, but I’ve never met a woman who wanted to spend those years hungry, and it isn’t on Laura’s plan or mine.
In September, pelacarsen, the first drug built to lower Lp(a) to finish a large outcomes trial, lowered Lp(a) in more than 8,000 people who already had heart disease but didn’t significantly reduce major cardiovascular events.[16][17] Several other Lp(a) drugs are still in trials.[17]
Her ApoB became the number we follow, because it counts the particles that do the damage, Lp(a) included. Her LDL stays on the report as the foundation.[3] I put her estradiol, FSH, LDL, ApoB, and Lp(a) on one graph, so we can watch them move together as her hormones change. And her Lp(a) gets rechecked, so we know whether that 30% jump is a trend or a blip.
This is the plan that fits Laura’s body, history, and goals. While your plan may look different, I hope her case gives you ideas about what to consider and discuss with your clinician. I wrote a list of bullet points at the end for you to take to your next appointment.
It’s a health hazard to be a woman. Heart health is one of the places I see it most clearly because a woman has a heart attack about every 7 seconds. Women are 7 to 10 times more likely to die of heart disease than breast cancer. If you’re more scared about breast cancer, I get it, but please be vigilant about heart disease too.
Medicine tends to measure what’s easy to measure and then treat the result as the answer, so a woman’s cholesterol comes back in range, the patient portal shows a cheerful green dot, someone types “normal, recheck in a year,” and the…
