Most adults have had their blood pressure read hundreds of times and left the appointment focused on two numbers: the top and the bottom. What almost none of them have been told is that those same two numbers contain a third metric their doctor rarely mentions – and that a completely separate pair of markers, one from a standard blood panel and one from a simple vitamin test, may combine to reveal a level of heart risk that neither one flags on its own.
The blood pressure piece of this story comes from a 26-year study led by Dr. Michael Hecht Olsen, a hypertension and cardiovascular prevention professor at the University of Southern Denmark. Dr. Olsen found that mean arterial pressure – MAP – which takes both systolic and diastolic readings into account, is a strong indicator of cardiovascular risk at any age. MAP represents the average pressure in your arteries during a heartbeat and is calculated using both blood pressure numbers. The study tracked 107,599 adults ranging in age from 19 to 97, none of whom had heart disease at enrollment, over more than two decades of follow-up. The finding reframes something most people think they already understand.
A research team examined two markers that are almost never checked together – a measure of how well your body handles insulin, and your vitamin D level – and found that the combination does something that neither factor does independently. Before getting to what they found, it helps to understand why the blood pressure conversation needed updating first.
The Blood Pressure Numbers You Actually Know – and the One You Don’t
Blood pressure has two numbers: systolic, recorded when the heart contracts and pumps blood, and diastolic, recorded when the heart relaxes. For decades, systolic pressure received most of the clinical attention, particularly in older adults. That focus wasn’t wrong, but it was incomplete.
The University of Southern Denmark study found that mean arterial pressure was a good measure of cardiovascular risk and death at any age. Dr. Olsen noted: “Our results underline the importance of measuring not only the systolic but also the diastolic blood pressure, especially in individuals younger than 50.” For anyone under 50 in particular, the bottom number carries more predictive weight than most clinicians currently give it credit for.
MAP is the average pressure in a person’s arteries during one cardiac cycle, calculated using both diastolic and systolic blood pressure. It’s not a number that appears on your standard printout, but it’s derived directly from the readings you already receive. A 2023 analysis published in a cardiovascular medicine journal found that MAP has demonstrated superior predictive capability compared to systolic and diastolic pressure alone for forecasting cardiovascular disease risk. Two numbers that look fine in isolation can produce a MAP that signals elevated risk.
The underlying stakes are not abstract. The American Heart Association notes that systolic readings remain a strong predictor of cardiovascular risk across all age groups, independent of sex and other risk factors – but that both numbers matter and the one that’s abnormal is the one clinicians act on. And according to data from the CDC, nearly half of U.S. adults – 48.1%, or about 119.9 million people – already meet the threshold for high blood pressure, defined as a systolic reading at or above 130 mmHg or a diastolic reading at or above 80 mmHg. In 2024, high blood pressure was a primary or contributing cause of 680,179 deaths in the United States.
The incremental risk from even modest elevation in either number is steeper than most people realize. A 2025 analysis covered by Healthline found that a 10 mmHg higher systolic blood pressure was associated with a 27% higher risk of heart disease and a 22% higher risk of kidney disease. A 5 mmHg higher diastolic reading was linked to a 20% higher risk of heart disease and 16% higher kidney disease risk. These are not worst-case scenarios. They describe the difference between a reading that passes and one that doesn’t quite clear the threshold.
The Two Numbers No One Is Checking Together
While the blood pressure conversation has been slowly evolving, a parallel line of research has been quietly building around two metabolic markers that most primary care panels already measure – just never in combination.
The first is the triglyceride-glucose index, commonly called the TyG index. It is a measure of insulin resistance – how well your body responds to insulin – calculated from triglyceride and glucose levels already on a standard blood panel. Insulin resistance is the state where your cells stop responding efficiently to insulin, forcing the pancreas to produce more of it to keep blood sugar in check. Insulin resistance has been associated with adverse cardiac remodeling and dysfunction that increases heart failure risk over time. A 2022 study in PLOS ONE found that a higher TyG index is an independent and causal risk factor for incident heart failure in the general population.
The second marker is vitamin D. Vitamin D deficiency does a lot more than affect bone health. It also plays a role in how blood vessels function, how the body manages inflammation, and how blood pressure is regulated. A 2019 news article from the American Heart Association noted that low blood levels have been linked to an increased risk of heart attacks and strokes. Vitamin D deficiency is also far more common than most people assume – a 2021 review in the journal Nutrients found it occurs in approximately 30 to 50% of the population across all ethnicities and age groups.
Researchers publishing in Frontiers in Nutrition drew on the UK Biobank – a prospective cohort of 335,206 adults who had no cardiovascular disease at enrollment – to examine what happens when both the TyG index and vitamin D levels are simultaneously off. That combination hadn’t been studied before. Both factors are common and largely silent, and doctors typically assess them separately rather than together.
The findings were direct. A high TyG index combined with vitamin D deficiency significantly increased the risk of a major adverse cardiovascular event – including ischemic heart disease, stroke, sudden cardiac arrest, and cardiovascular death – by 26%. Neither marker produced that level of risk elevation on its own. The combination amplified the danger in a way that routine testing, which evaluates each number in a silo, would miss entirely.
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An earlier UK Biobank analysis examining more than 403,000 participants found that those in the highest quartile of TyG index had a 19% increased risk of total cardiovascular disease compared to those with the lowest TyG scores – even after adjusting for traditional risk factors. Separately, a 2025 study published in the journal Nutrition found that regular vitamin D supplementation was associated with a 6% decreased risk of atherosclerotic cardiovascular disease and a 10% reduced risk of ischemic heart disease.
The two markers interact biologically in ways that aren’t yet fully mapped, but there are plausible mechanisms. Vitamin D plays a role in regulating insulin sensitivity, and low levels may make the metabolic dysfunction captured by the TyG index worse. A 2014 study in Circulation Research found that people with very low vitamin D levels – below 37.5 nmol/L – had roughly twice the relative risk of myocardial infarction compared to those with levels above 75 nmol/L.
What to Do With This Information
Insulin resistance and vitamin D deficiency have each been implicated in cardiovascular disease development, yet their joint effects on major adverse cardiovascular events remain unclear across all demographic subgroups. The UK Biobank cohort skews toward participants of White European ancestry, which limits how broadly the specific risk figures can be generalized. The 26% figure is a meaningful signal, not a guarantee.
What the research does make clear is that standard cardiovascular checkups are missing something. A person whose blood pressure looks acceptable, whose cholesterol is controlled, and who has no formal diagnosis may still carry a TyG index and vitamin D level that, together, represent a clinically meaningful risk profile. That combination doesn’t trigger a flag on any standard panel because no one is currently programmed to look at both numbers at once.
The practical steps are concrete. If you haven’t had your fasting triglycerides and blood glucose measured recently, request them – they’re typically included in a standard metabolic panel. Your TyG index can be estimated from those two values (the calculation is widely available online, or your doctor can run it). For vitamin D, a 25-hydroxyvitamin D blood test is the standard measure; levels below 50 nmol/L (20 ng/mL) are generally classified as deficient. If your vitamin D is low, the most reliable correction pathways are sun exposure, dietary sources like fatty fish and egg yolks, and supplementation under physician guidance.
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The Bottom Line
A 2025 study highlighted by the American Heart Association found that adults with heart disease who took vitamin D doses tailored to reach optimal blood levels reduced their risk of heart attack by more than 52% compared to those who weren’t monitored. For insulin resistance, lifestyle remains the most evidence-backed lever: regular strength training, cutting back on ultra-processed foods, prioritizing sleep, and managing chronic stress. These approaches carry no waiting period and no prerequisite diagnosis.
The larger point is that blood pressure numbers and metabolic markers have each been studied in isolation for decades. The research now suggests the more clinically useful question isn’t “is this number high?” but “what does this number look like next to the others?” Asking your doctor to run a full metabolic panel alongside a 25-hydroxyvitamin D test, and to calculate your TyG index from the results, costs nothing extra and could surface a risk profile that no single number alone would reveal.
Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis, or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.
AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.