A study of more than 5,500 people suggests that monitoring hormone levels and managing weight may help reduce the risk of premature death.
For adults over 50, excess abdominal fat and low vitamin D levels may form a particularly dangerous combination. A study of more than 5,500 people found that participants with both conditions had a 123% higher risk of death than those with neither.
The findings, published in Diabetes, Obesity, and Metabolism, indicate that abdominal obesity and vitamin D deficiency are each associated with increased mortality on their own. When they occur together, however, the risk rises substantially.
“Abdominal obesity is a well-known risk factor because it’s associated with inflammation and metabolic problems. Vitamin D, on the other hand, is a hormone that acts on various organs, and its deficiency impairs several bodily functions. When these two conditions occur together, one amplifies the effects of the other, further increasing the risk of death,” explains Tiago Silva Alexandre, a professor in the Department of Gerontology at the Federal University of São Carlos (UFSCar) in Brazil, who coordinated the study. “For that reason, monitoring vitamin D levels and treating excess abdominal fat are essential measures to prevent premature death, especially after age 50,” he adds.
The researchers followed 5,520 adults aged 50 and older for six years. Participants belonged to the English Longitudinal Study of Ageing (ELSA), one of the largest studies of aging in the world.
The project was conducted with University College London (UCL) in the United Kingdom and funded by FAPESP.
Combined risks more than double mortality
The investigators first examined the two conditions separately. Vitamin D deficiency, defined as a level below 30 nmol/L, was associated with a greater mortality risk than abdominal obesity alone.
Abdominal obesity was defined as a waist circumference greater than 102 centimeters in men or 88 centimeters in women. Participants with abdominal obesity alone had a 47% higher risk of death, while those with vitamin D deficiency alone faced an increase of up to 91%.
When both conditions were present, the associated risk of death rose by 123%, more than twice the risk observed among participants with neither condition.
Abdominal fat traps vitamin D
Alexandre said the findings point to a cycle in which the two conditions may reinforce each other. Abdominal fat can “sequester” vitamin D circulating through the body, storing it in adipocytes (fat cells) and reducing the amount available in the bloodstream.
“This means that although the body may have the vitamin stored in fat, it isn’t freely available in the blood to perform vital functions in other organs and systems,” he says.
People with obesity also have lower expression of the enzymes needed to metabolize vitamin D, further limiting the amount the body can use.
“Abdominal obesity reduces circulating vitamin D, and that deficiency impairs the immune system, exacerbating the chronic inflammation caused by excess fat and drastically increasing the risk of mortality,” Alexandre explains to Agência FAPESP.
Aging adds another layer to this relationship. Older adults naturally experience inflammaging, a persistent state of low-grade inflammation that develops with age.
“Under normal conditions, vitamin D acts as a regulator of the immune system, preventing inflammation from getting out of control. When vitamin D levels are low, and there’s excess abdominal fat, an unfavorable systemic environment develops that accelerates cardiovascular and metabolic diseases, as well as muscle loss,” he stresses.
Deficiency may affect broader aging
The research is part of a broader series of studies examining how vitamin D affects health during aging.
“In previous studies, we identified a cascade effect. Vitamin D deficiency leads to a loss of strength, which results in reduced walking speed, causing a loss of independence and greater dependence in daily activities,” Alexandre explains.
Separate research by the same group also found that vitamin D deficiency was associated with a higher risk of cognitive decline.
“Vitamin D is a hormone with various functions. It plays a role in regulating blood pressure, heart rate, the central nervous system, the immune system, and the endocrine system. Therefore, when its levels are low, several essential bodily functions are compromised,” he says.
Reference: “Does the Combination of Abdominal Obesity and Vitamin D Deficiency Increase the Risk of Death in Individuals Aged 50 or Older? Evidence From the ELSA Study” by Joyce da Silva Milliati, Thaís Barros Pereira da Silva, Roberta de Oliveira Máximo, Mariane Marques Luiz, Sara Souza Lima, Andrew Steptoe, Cesar de Oliveira, Tiago da Silva Alexandre and Joyce da Silva Milliati, 06 May 2026, Diabetes, Obesity and Metabolism.
DOI: 10.1111/dom.70839
The present study was supported by the Economic and Social Research Council (Grant Number: ES/T008822/11), the National Council for Scientific and Technological Development (CNPq) (Grant No. 305338/2023-4, awarded to TSA), and the São Paulo Research Foundation (FAPESP) (Grant No. 2024/01918-6, also awarded to TSA).
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