Infections May Fuel Frailty, Especially With Obesity

Study finds history of infections linked to higher frailty levels, with obesity potentially shaping that relationship.

Published on Mar. 5, 2026

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A study of over 1,400 older adults found that having a history of infections was significantly associated with higher frailty levels. The relationship was more pronounced in those over 65, and obesity appeared to play a role in mediating the link between infections and frailty. The findings suggest infections may accelerate the decline towards frailty, and clinicians should emphasize the importance of preventive measures like vaccinations.

Why it matters

This study flips the previously understood relationship between frailty and infections, suggesting infections may be a driver of frailty rather than just a consequence. The insights could help clinicians better understand the factors contributing to frailty in older adults and reinforce the value of preventive measures like vaccinations.

The details

The study analyzed data from over 1,400 participants in the Baltimore Longitudinal Study of Aging. It found that having a history of infections was significantly linked to higher frailty index scores, and this relationship was more pronounced in those over 65. Specific infection types like pneumonia, urinary tract infections, herpes, and viral infections were associated with greater frailty. Inflammation and obesity biomarkers like leptin and BMI appeared to help shape the relationship between infections and frailty.

  • The study included participants from the ongoing Baltimore Longitudinal Study of Aging.

The players

Luigi Ferrucci

MD, PhD, of the National Institute on Aging in Baltimore, and lead author of the study.

Sandra Shi

A geriatrician and researcher at the Marcus Institute for Aging Research in Boston, who commented on the study's findings.

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What they’re saying

“Our study found that participants with a previous history of infections had higher burden of frailty. These results suggest that infections could accelerate a process of molecular or immunological impairment that clinically emerges as a faster decline towards the development of frailty.”

— Luigi Ferrucci, MD, PhD (Journals of Gerontology: Series A)

“It's getting at some of the new directions frailty research is going. Why is somebody frail, and what's driving that? This is one of the first studies to examine infections as possibly a cause of frailty.”

— Sandra Shi, Geriatrician and researcher (MedPage Today)

What’s next

The study's authors note that future research is needed to better understand the mechanisms by which infections may contribute to frailty, as well as the role of infection severity and duration.

The takeaway

This study suggests that even relatively minor infections may have long-term impacts on older adults' health, potentially accelerating the development of frailty. Clinicians should emphasize the importance of preventive measures like vaccinations to help reduce infection risk and potentially slow the progression towards frailty.