For most of human history, living to 100 was incredibly rare — a milestone so unusual that it was almost legendary. Today, thanks to advances in medicine, hygiene, and daily living, more people than ever are reaching that age. Even so, the question remains: why do some people live so much longer than others?
A group of Swedish researchers set out to explore that question by examining something surprisingly simple — routine blood tests taken many years before participants reached old age. Instead of focusing on special diets or supplements, they studied common lab markers that people regularly have checked during normal healthcare visits.
Using the AMORIS cohort, a large clinical dataset from Stockholm County, researchers reviewed health information from more than 44,000 people born between 1893 and 1920. All participants had basic blood tests done between 1985 and 1996, roughly at similar ages, which allowed for fair comparisons. They were then tracked until death or the end of 2020. Out of the group, 1,224 individuals lived to 100 — most of them women, reflecting global longevity trends.
Because Sweden’s national registers are comprehensive, the team was able to connect lab results with long-term health outcomes. They analyzed 12 common biomarkers, including glucose, cholesterol, creatinine, iron levels, liver enzymes, and uric acid. These are the same markers most adults see on a typical blood panel.
One of the most discussed findings involved cholesterol. The study showed that very low cholesterol was linked with lower odds of reaching 100, while moderately high or average levels were not associated with increased risk. The researchers explained that extremely low cholesterol can sometimes signal frailty or underlying illness. In general, both very low and very high extremes across several markers were connected with lower chances of exceptional longevity.
Continue reading on the next page…