Reaching 100 is becoming more common, but researchers asked whether routine blood tests taken years earlier could hint at who might achieve this milestone. A Swedish study followed tens of thousands, checking biomarkers like glucose and cholesterol to see their link with living past 90 or 100.

The study compared midlife lab results of people who eventually reached 100 with peers who did not. Researchers examined “markers of metabolism, kidney and liver function, iron status, and inflammation,” following participants for up to 35 years. This long-term approach allowed meaningful conclusions.

Using the AMORIS cohort, 44,636 people born between 1893 and 1920 were analyzed. Over time, 1,224 reached age 100, mostly women. Swedish national registers ensured accurate tracking of diseases and deaths, and statistics helped reveal key patterns.

Twelve routine markers were studied, including glucose, cholesterol, creatinine, liver enzymes, albumin, iron, total iron-binding capacity, and uric acid. The authors noted, “low cholesterol—not high cholesterol—was linked with reduced odds of reaching 100,” while very low iron also lowered the chances. High glucose was particularly harmful, with “people in the highest ranges [showing] the lowest odds of becoming centenarians.”

Kidney and liver markers mattered too: “High creatinine and elevated liver enzymes were tied to lower odds of exceptional longevity.” Uric acid levels also showed a pattern: the lowest levels were linked with higher chances of reaching 100, suggesting lower chronic inflammation. Overall, extremes—very high or very low lab values—tended to reduce longevity, highlighting the importance of balanced metabolic and organ health over time.