International Journal of ObesityOct 30, 2026, 02:04 GMT

Internal fat rose with age despite similar body mass index

An observational study of 36,831 UK Biobank participants aged 45–82 linked fat distribution to disease risk, with repeat scans in 1,688.

Paper by Mathias Rask-Andersen, Valeria Lo Faro, Torgny Karlsson, Åsa Johansson · Uppsala University

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Populations

Studied:: Cohort study of 1,688 UK Biobank participants with repeat scans (Independent replication)
What changed:: Fat around abdominal organs and within the pancreas and thigh muscles increased between scans despite similar body mass index
The catch:: Only 1,688 participants had repeat scans; their age-related fat changes could differ from others
Why it’s aging research:: It looks at how biology varies with age or lifespan.

Editor of record: Boris Djordjevic · AgingResearch.News

Paper

In an observational study of 36,831 UK Biobank participants aged 45–82, researchers examined body scans and subsequent disease risk. A subgroup of 1,688 had repeat scans.

Fat around abdominal organs and fat within the pancreas and thigh muscles were higher at older ages and increased between scans, despite similar body mass index, a measure relating weight to height. After accounting for body mass index and multiple statistical tests, associations between scan-based measures and disease risk remained significant only for type 2 diabetes and high blood fat levels. Fat around abdominal organs had the strongest association with type 2 diabetes and accounted for a substantial share of the risk traditionally attributed to body mass index. Genetic analyses supported this association. Adding scan-based measures improved risk prediction beyond body mass index, particularly in males.

Why it matters

For assessing disease risk as people age, the authors suggested that more practical tools or biological markers capturing fat around and within organs may improve assessment beyond body mass index.

Caveats

These observational and genetic analyses identified associations, not proof of cause and effect. The findings do not establish the same patterns in people outside the studied age range of 45–82.