Living to 100 was once considered almost mythical, something achieved by only a few people. In earlier centuries, disease, poor nutrition, and limited medical knowledge meant most people did not live far beyond their sixties. Today, however, longer life spans have become more common thanks to improvements in medicine, sanitation, and public health. Even so, reaching 100 remains rare, and scientists continue searching for the factors that help some people achieve such exceptional longevity.

Researchers in Sweden explored this question using long-term health data from national medical records. By studying blood tests and health markers collected decades earlier, they looked for patterns among people who eventually lived past 90 or even 100. Their goal was not to predict individual futures but to identify “probabilities, patterns, and tendencies that emerge only when large populations are studied over long periods of time.”

The study found that certain health markers earlier in life were linked to longer lifespans. People who lived the longest often had more stable blood glucose levels, balanced cholesterol, lower levels of inflammation, and better kidney function. None of these factors guaranteed a long life, but together they suggested a body better able to manage the stresses of aging.

Researchers also examined genetic factors, including blood type. Some earlier studies have suggested that certain blood types may be associated with slightly lower risks of cardiovascular disease or blood clotting disorders. However, scientists emphasize that blood type alone does not determine how long someone will live.

Overall, the research shows that longevity usually results from many small advantages accumulated over time. As the study suggests, long life reflects “cumulative patterns rather than single causes.” Healthy habits, medical care, and biological balance all work together to shape how the body ages over a lifetime.