Low vitamin D and a large waistline may each be risky on their own — but together, they appear to be considerably more dangerous, a new study of older adults suggests.
Researchers in Brazil (with University College London) followed 5,520 adults aged 50 and older for six years, using data from the English Longitudinal Study of Ageing. People who had both abdominal obesity and vitamin D deficiency (levels below 30 nmol/L) had a 123% higher risk of death than those with neither. Individually, abdominal obesity was linked to a 47% higher risk and vitamin D deficiency to up to a 91% higher risk. The study appeared in 2026 in Diabetes, Obesity and Metabolism.
Why the two interact
The researchers point to a biological link: abdominal fat “sequesters” vitamin D inside fat cells, lowering how much is available in the bloodstream, while also impairing the body’s vitamin D metabolism. “When these two conditions occur together, one amplifies the effects of the other, further increasing the risk of death,” said researcher Tiago Silva Alexandre.
How to read it
This is an observational study — it shows a strong association, not that low vitamin D or belly fat directly cause death, and people with both may differ in other ways. Still, it reinforces attention to two modifiable factors. Anyone concerned about vitamin D or waist size should talk with a clinician rather than self-supplement based on a single study.
This article summarizes an observational study and is not medical advice. Talk to a healthcare professional about vitamin D testing, supplements, or weight management.