Delving into Longevity with Centuries-Old Blood Tests

Centenarians , once considered rare, have become commonplace . In fact, they are the fastest growing demographic of the world’s population, with numbers approximately doubling every ten years since the 1970s.

Figure : Quantiles (10, 25, 50, 75, 90) of biomarkers for centenarians and non-centenarians. Green areas show the normal range of each biomarker based on commonly used clinical thresholds (see Supplementary Table 1 for details). Multiple imputed data were used and 44,636 participants were included. TC: total cholesterol; ALAT, alanine aminotransferase; ASAT, aspartate aminotransferase; GGT, gamma-glutamyl transferase; ALP, alkaline phosphatase; TIBC, total iron binding capacity. 

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How long humans can live and what determines a long, healthy life have been of interest for as long as we know. Plato and Aristotle discussed and wrote about the aging process more than 2,300 years ago.

However, the quest to understand the secrets behind exceptional longevity is not easy. It involves unraveling the complex interplay of genetic predisposition and lifestyle factors and how they interact throughout a person’s life. Now, our recent study, published in GeroScience , has revealed some common biomarkers, including cholesterol and glucose levels , in people living beyond 90 years.

Nonagenarians and centenarians have long been of great interest to scientists, as they can help us understand how to live longer and perhaps also how to age in better health. Until now, studies on centenarians have often been small-scale and focused on a selected group, excluding, for example, centenarians living in nursing homes.

Huge data set

Ours is the largest study comparing biomarker profiles measured across the lifespan between exceptionally long-lived people and their shorter-lived peers to date.

We compared the biomarker profiles of people who lived to be over 100 years old and their shorter-lived peers, and investigated the link between the profiles and the chance of becoming a centenarian.

Our research included data from 44,000 Swedes who underwent health assessments between ages 64 and 99; They were a sample of the so-called Amoris cohort. These participants were then followed through Swedish registry data for up to 35 years. Of these people, 1,224, or 2.7%, lived to be 100 years old. The vast majority (85%) of centenarians were women .

Twelve blood biomarkers related to inflammation, metabolism, liver and kidney function, as well as possible malnutrition and anemia were included . All of these have been associated with aging or mortality in previous studies.

The biomarker linked to inflammation was uric acid , a body waste product caused by the digestion of certain foods. We also analyzed markers related to metabolic status and function , including total cholesterol and glucose, and those related to liver function, such as alanine aminotransferase (Alat), aspartate aminotransferase (Asat), albumin, gamma-glutamyl transferase (GGT), alkaline phosphatase. (Alp) and lactate dehydrogenase (LD).

We also looked at creatinine, which is related to kidney function, and iron and total iron binding capacity (TIBC), which is related to anemia. Finally, we also investigated albumin, a biomarker associated with nutrition.

Results

We found that, in general, those who lived to be one hundred years old tended to have lower levels of glucose, creatinine, and uric acid starting at age sixty. Although median values ​​did not differ significantly between centenarians and non-centenarians for most biomarkers, centenarians rarely showed extremely high or low values.

For example, very few centenarians had a glucose level above 6.5 earlier in their life, or a creatinine level above 125.

For many of the biomarkers, both centenarians and non-centenarians had values ​​outside the range considered normal in clinical guidelines. This is probably because these guidelines are set based on a younger, healthier population.

When exploring which biomarkers were related to the probability of turning 100, we found that all but two (alat and albumin) of the 12 biomarkers showed a connection with the probability of turning 100. This was even after taking into account age, sex and disease burden. .

People in the lowest levels of five total cholesterol and iron groups were less likely to reach age 100 compared to those with higher levels. Meanwhile, people with higher levels of glucose, creatinine, uric acid and markers of liver function also decreased their chances of becoming centenarians.

In absolute terms, the differences were quite small for some of the biomarkers, while for others the differences were somewhat more substantial.

In the case of uric acid , for example, the absolute difference was 2.5 percentage points. This means that people in the group with the lowest uric acid level had a 4% chance of turning 100, while in the group with the highest uric acid levels only 1.5% reached 100. years.

Even if the differences we discovered were overall quite small, they suggest a potential link between metabolic health, nutrition, and exceptional longevity .

However, the study does not allow conclusions to be drawn about which lifestyle factors or genes are responsible for the biomarker values. However, it is reasonable to think that factors such as nutrition and alcohol intake play a role. It’s probably not a bad idea to track kidney and liver values, as well as glucose and uric acid as we age.

That said, chance is likely to play a role in reaching an exceptional age at some point. But the fact that differences in biomarkers could be seen long before death suggests that genes and lifestyle may also play a role.

Source : Centenarian blood tests give hints of the secrets to longevity. The Conversation