Reaching the age of 100 used to be quite a rare achievement. Yet, nowadays, it seems to be a rather commonplace occurrence. Well, believe it or not, centenarians are not the fastest-growing demographic age group worldwide. Researchers in Sweden followed tens of thousands of people and analyzed routine blood tests taken years earlier. They then posed a question regarding the potential link between blood type and longevity. Do common lab markers hint at who reaches 100 years of age? The study revealed some of those common biomarkers, including glucose and cholesterol levels, in individuals who live past 90. The work has been published in a respected journal and made use of linked national registers; therefore, it draws on strong data. In this article, we will walk through what they measured and how they analyzed it.

The team wanted to know whether simple blood tests, collected many years earlier, relate to exceptional longevity. Exceptional here means living to at least 100. They compared people who reached 100 with peers who did not. The participants all had their blood tests taken when they were about the same age. This is essential, since comparing a 70-year-old with a 90-year-old can confuse any signal. The study included standard markers of metabolism, kidney and liver function, iron status, and a measure tied to inflammation. The design used a long follow-up period, which would help to strengthen the conclusions. Participants were tracked for as long as 35 years after the first blood draw, using Swedish registers that record disease, deaths, and residence.

The authors put it plainly in their abstract: “Participants were followed in Swedish register data for up to 35 years.” We will return to the exact markers next, and then to the outcomes. For now, let’s focus on this specific core idea. The research does not claim that a single test guarantees a long life. It looks at patterns across a population and estimates the odds of reaching 100 for different ranges of each marker. That approach helps us see broader trends. It cannot tell exactly what will happen to one person. However, it can suggest where healthy targets may lie overall. It can also highlight which very low or very high values deserve attention. The analysis adjusted for age, sex, and a comorbidity index, which reduces some bias.

The research used the AMORIS cohort. AMORIS is a population-based resource built from clinical laboratory testing in Stockholm County. It includes more than 800,000 people, but this study focused on 44,636 participants born between 1893 and 1920 who had blood tests between 1985 and 1996. Everyone was followed from the first test until death, or until the end of 2020. During follow-up, 1,224 people reached their 100th birthday. About 85% of the centenarians were women, which reflects broader survival patterns in Sweden at that time. The team linked the lab data to several national registers using Swedish personal identification numbers. That allowed accurate tracking of diseases and deaths. The analysis used descriptive statistics, logistic regression, and clustering.