Rising Number of Centenarians

Centenarians, who were once a rarity, have now become increasingly common. In fact, they represent the fastest-growing demographic globally, with their numbers nearly doubling every decade since the 1970s.

The question of how long humans can live and what contributes to a healthy lifespan has captivated minds for centuries. Think about it—Plato and Aristotle were already discussing the aging process over 2,300 years ago.

However, figuring out the secrets to exceptional longevity is quite a complex task. It involves understanding the intricate relationship between genetic factors and lifestyle choices, as well as their interactions over a person’s lifetime.

Our recent study, published in GeroScience, identified common biomarkers such as cholesterol and glucose levels in those who reach age 90 or older.

Scientists have long been fascinated by nonagenarians and centenarians, believing they could offer insights into living longer—and potentially aging more healthily. Historically, studies focused on centenarians have often been small and selective, frequently omitting those who reside in care facilities.

Comprehensive Study

Our research is the most extensive to date, comparing biomarker profiles over a lifetime among exceptionally long-lived individuals and those who lived shorter lives. We examined the biomarker profiles of people who made it to 100 years old, comparing them to their peers and looking for correlations between these profiles and the odds of reaching such an advanced age.

The study involved data from 44,000 Swedes who underwent health assessments from ages 64 to 99, part of what’s known as the Amoris cohort. They were subsequently tracked through Swedish registers for up to 35 years. Among these participants, 1,224 (or 2.7%) achieved the milestone of turning 100, with a significant majority—85%—being women.

Twelve blood-based biomarkers associated with inflammation, metabolism, liver and kidney function, as well as indicators of potential malnutrition and anemia, were examined. Previous studies have linked these biomarkers to aging and mortality.

One notable biomarker related to inflammation was uric acid, a byproduct of digesting certain foods. We also explored markers concerning metabolic health, such as total cholesterol and glucose, alongside those related to liver function, including alanine aminotransferase, aspartate aminotransferase, albumin, and others. We even measured creatinine, linked to kidney function, and factors related to iron status and nutrition.

Key Findings

Our findings indicated that individuals who reached their hundredth birthday typically had lower levels of glucose, creatinine, and uric acid starting from their sixties. While median values didn’t show significant differences between centenarians and those who didn’t reach that age for most biomarkers, centenarians rarely exhibited extremely high or low levels.

For instance, very few centenarians showed glucose levels above 6.5 mmol/L earlier in life or creatinine levels over 125 µmol/L. Both groups had values that diverged from what’s considered normal based on clinical guidelines, likely because these guidelines are based on younger populations.

In terms of biomarkers linked to the likelihood of reaching 100, nearly all except two (alanine aminotransferase and albumin) correlated with increased chances of becoming a centenarian, even after controlling for factors like age, sex, and disease burden. Those in the lowest quintile for total cholesterol and iron levels had lower odds of living to 100 compared to those with higher levels.

Conversely, individuals with elevated glucose, creatinine, uric acid, and liver function markers also faced reduced chances of becoming centenarians. While some disparities were relatively small, others were more pronounced. For example, regarding uric acid, the absolute difference was 2.5 percentage points; individuals with low uric acid had a 4% chance of reaching 100, whereas those with high levels had only a 1.5% chance.

Though overall differences may appear modest, they hint at potential connections between metabolic health, nutrition, and extraordinary longevity. Still, we can’t definitively conclude which lifestyle choices or genetic factors account for the observed biomarker levels.

That said, it seems logical to consider that factors like diet and alcohol consumption could influence these results. Monitoring kidney and liver functions, along with glucose and uric acid levels as one ages, might be wise.

Of course, chance likely plays a role in reaching such an exceptional age. Yet the fact that we can observe differences in biomarkers long before reaching that stage suggests that both genetics and lifestyle choices do matter.