Here’s what you’ll learn when you read this story.

• Researchers found that centenarians often don’t have “perfect” biomarkers, but stay in balanced, moderate ranges.
• They have resilience to the typical markers that predict disease, like high total cholesterol and declining kidney function, possibly because their bodies tolerate stress better.
• Longevity is also shaped by diverse factors like race, access to care, lifestyle, and long-term stability, not just biology. These aspects need more research.

Ida Mae Hunter, a 100-year-old Black woman living in Selma, Alabama, still attends church and sings her favorite hymn “Shine On Me.” Her bloodwork, unremarkable at first glance, tells a more complicated story. Her A1C is elevated, her kidneys show mild strain, and she lives with Alzheimer’s disease. Yet she has outlived nearly everyone in her cohort. For scientists trying to understand longevity, people like her are not contradictions. They are the key.

A Paradox Hides in Their Blood

For decades, aging research focused on avoiding disease, keeping cholesterol low, blood sugar controlled, organs functioning within textbook “normal” ranges. But centenarians consistently challenge that model. Their bloodwork often doesn’t look perfect. In fact, it sometimes looks concerning.

And yet, they live.

A landmark investigation from Sweden, often referred to as the “super-ager blood study,” has helped reframe the conversation. Researchers analyzed tens of thousands of individuals over decades, tracking biomarkers like cholesterol, glucose, uric acid, and markers of inflammation. The published findings suggest that longevity isn’t about perfection.

Centenarians, the study found, tend to cluster within moderately optimal ranges across many biomarkers, not necessarily the lowest or highest extremes. They avoid the danger zones, but they don’t always fit the idealized profiles promoted in midlife medicine. That nuance matters.

Jordan Weiss, PhD, assistant professor, NYU Grossman School of Medicine, explained that the authors found that both centenarians and non-centenarians had alkaline phosphatase and lactate dehydrogenase levels above what clinical guidelines consider normal, but those guidelines were calibrated to younger, healthier populations. Higher total cholesterol does not decrease the likelihood of reaching 100, which runs directly counter to what we’d tell a 50-year-old. “So if a 78 year old comes in with mildly elevated cholesterol, the move might be to reach for a statin,” said Weiss, “but in this age group, that elevated number may actually be a marker of resilience, not risk. We need to revisit age-adapted reference ranges.”

Their Bodies Defy the Normal Model

Ida Mae would not be flagged as a model patient by most predictive health tools. With an A1C of 7.7 and creatinine of 1.05, she is diabetic with declining kidney function. In a younger patient, these numbers would trigger aggressive intervention. But longevity doesn’t always follow clinical logic. Her cholesterol profile, total cholesterol at 135, LDL at 53, is low and protective. Her liver enzymes are normal. More importantly, she has made it to 100 despite carrying risk factors that, statistically, should have shortened her life. This is the central paradox of centenarian biology. The presence of disease does not preclude exceptional longevity.

Researchers in the field of gerontology increasingly believe that what distinguishes centenarians is not the absence of illness, but a unique ability to tolerate it.

This Is What the Swedish Study Actually Found

The Swedish cohort study, drawing from national health registries and long-term blood data, identified several key patterns among those who reached 100. They have lower, but not extreme, levels of glucose and elevated creatinine. Participants tended to avoid the highest-risk categories, even if they weren’t perfectly controlled. While some participants had balanced cholesterol levels, even extremely low or high cholesterol did not increase or decrease the likelihood of reaching 100. Stability, not minimization, was protective. Elevated uric acid, linked to inflammation and metabolic stress, was a strong predictor of mortality. Perhaps most importantly, centenarians showed less volatility in their biomarkers across decades.

This last point may be the most revealing. Longevity may depend less on hitting optimal numbers at a single point in time, and more on maintaining physiological equilibrium over years. “Maintaining good function across multiple systems can lead to a higher likelihood of surviving longer,” said lead study author Shunsuke Murata, PhD.

Slow Aging Requires a Balancing Act

To understand why someone with diabetes and mild kidney dysfunction can still live past 100, scientists are exploring a concept sometimes described as “biological buffering.” It refers to the body’s ability to absorb stress—metabolic, inflammatory, environmental—without tipping into catastrophic failure. “It's a balancing act. Centenarians (in the study) didn't have one biomarker that was spectacularly good. They had a profile, across metabolism, liver function, kidney function, inflammation, and nutrition, that was consistently more favorable. It's the overall pattern that mattered,” explained Weiss.

In younger individuals, elevated glucose might trigger a cascade of vascular damage, kidney decline, and cardiovascular disease. In centenarians, those same stressors appear to unfold more slowly, or are counterbalanced by protective mechanisms we don’t fully understand.

In the study, higher cholesterol did not decrease the likelihood of reaching 100. Murata says that this requires careful interpretation. The study divided the population into five groups by cholesterol level. Only the lowest cholesterol group had a lower probability of reaching 100 compared to the middle group. Low cholesterol was associated with a reduced likelihood of reaching the age of 100. “This does not mean high cholesterol is beneficial,” reiterated Murata, “in older populations, very low cholesterol may reflect underlying illness or frailty rather than being a direct cause of shorter life.”

In other words, centenarian bodies bend without breaking.

Declining kidney function was another surprising biomarker. “The strength of the association with creatinine stood out to me,” said Murata, “this is a marker of kidney function, suggesting that kidney health may be an important contributor to exceptional longevity.”

The Link Between Race and Survival Is a Key But Overlooked Story

The study followed Swedes who are predominantly white, so extrapolation for a diverse United States population isn’t practical. In the United States, Black Americans face higher rates of chronic disease, reduced access to care, and shorter average life expectancy. Yet Black centenarians exist, and their biology may hold especially important insights. Historically, medical research has underrepresented minority populations, including in studies of aging. This raises a crucial question: are the pathways to longevity the same across different racial and socioeconomic groups? Or do they differ in ways that could reshape how we think about prevention and treatment?

Ida Mae’s survival is not just biological; it is social, environmental, and deeply contextual. “The more interesting question to me is what got her, as a Black woman in the US, to 100 despite societal and structural barriers the Swedish cohort almost certainly didn't face,” says Weiss, “that alone tells you something important is operating outside the biomarker panel, which usually includes some combination of deep social ties, consistent movement, a diet built on whole foods, and the psychological resilience to endure real hardship without being destroyed by it.”

Her blood tells one story. Her life tells another.

These Findings Could Help Others Live Longer

This is where science becomes both promising and complicated. On one hand, the insights from centenarian blood studies could lead to more sophisticated risk models. Instead of treating any deviation from “normal” as dangerous, clinicians could adopt a more individualized approach, one that considers stability, trends, and overall resilience.

For example, a slightly elevated A1C in an older adult might be managed conservatively if other markers are stable. Cholesterol targets could be personalized rather than universally minimized.

Greater emphasis could be placed on reducing variability, avoiding sharp swings in blood pressure, glucose, or weight. This aligns with a broader shift in medicine toward precision health.

“Centenarians are a natural model for healthy aging,” said Murata, “understanding the biological conditions associated with reaching very old age in good health could inform interventions aimed at compressing morbidity, extending the healthy period of life, not just its maximum length.” He emphasized, however, that further research is needed to clarify the lifestyle factors and other characteristics of populations who maintain good health for longer.

There is a danger in romanticizing centenarian biology. Just because some individuals live long lives with imperfect biomarkers does not mean those biomarkers are harmless. For every 100-year-old with diabetes, there are millions who suffer serious complications decades earlier.

Centenarians are, by definition, outliers. Their biology may not be replicable, or even desirable, in a broader population. Trying to mimic their profiles without understanding the underlying mechanisms could lead to worse outcomes, not better ones. This is the “survivor bias” problem. We see those who made it, but not the many who did not.

Back at the Kitchen Table

Ida Mae does not think of herself as a data point. She does not track her biomarkers or analyze her resilience. She lives, as she always has, within the rhythms of her own experience. Her blood, however, has become part of a larger story. One that challenges medicine to rethink its assumptions.

Longevity, it turns out, is not simply the absence of disease. It is the presence of something harder to define; durability, adaptability, perhaps even luck.

The Swedish study offers a framework, but not a formula. It tells us that living longer may depend less on achieving perfect numbers and more on maintaining balance over time. It suggests that the body’s capacity to endure may matter as much as its ability to prevent.

And it reminds us that the people who live the longest are not always the ones who look healthiest on paper.