Abdominal Obesity Combined With Vitamin D Deficiency More Than Doubles Death Risk After Age 50
核心洞察
A six-year study of 5,520 adults aged 50 and older found that having both abdominal obesity (搜索) and vitamin D deficiency (搜索) raised the risk of death by 123% compared with neither condition.
Vitamin D deficiency (搜索) alone (below 30 nmol/L) increased mortality risk by up to 91%, while abdominal obesity (搜索) alone raised it by 47%, but the combined effect was substantially greater.
Researchers attribute the interaction to abdominal fat sequestering vitamin D and lowering enzymes involved in its metabolism, which weakens immunity and worsens chronic inflammation.
A new study of more than 5,500 people over 50 has found that carrying excess weight around the belly and having low vitamin D levels sharply raise the risk of dying when the two conditions occur together. People over 50 who had both abdominal obesity (搜索) and vitamin D deficiency (搜索) were 123% more likely to die during the study period than those with neither condition, according to research published in the journal Diabetes, Obesity and Metabolism.
The research was carried out in collaboration with University College London (UCL) (搜索) in the United Kingdom and funded by FAPESP, a Brazilian research foundation. Researchers followed 5,520 people aged 50 and older for six years, drawing on data from the English Longitudinal Study of Ageing (ELSA), one of the world's largest studies focused on aging.
Individual and Combined Risks
Each condition on its own was already known to be dangerous. Vitamin D deficiency (搜索), defined as blood levels below 30 nanomoles per liter (nmol/L), was associated with a greater risk of death on its own than abdominal obesity (搜索), with an increase of up to 91%. Abdominal obesity, defined as a waist circumference greater than 102 centimeters for men and 88 centimeters for women, was associated with a 47% higher risk of death.
When both conditions were present, however, the risk of death rose by more than twofold. "Although each was associated with a higher risk of death on its own, the combined effect was substantially greater," the researchers reported.
A Reinforcing Biological Cycle
Tiago Silva Alexandre, a professor in the Department of Gerontology at the Federal University of São Carlos (UFSCar) (搜索) in Brazil who coordinated the study, explained that abdominal obesity (搜索) and vitamin D deficiency (搜索) may reinforce one another in a harmful cycle. Abdominal fat can "sequester" vitamin D circulating in the body, storing it in adipocytes (fat cells) instead of leaving it 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," Alexandre said.
Obesity may also interfere with the way the body processes vitamin D. People with obesity have lower expression of enzymes involved in vitamin D metabolism, further limiting how much of the vitamin is available for the body to use. "Abdominal obesity (搜索) 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 explained to Agência FAPESP.
The Role of Inflammaging
The combination may be particularly important later in life because aging itself is associated with "inflammaging," a state of low-grade chronic inflammation. "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," Alexandre stressed.
Clinical Implications
Alexandre said the findings point to two clear, practical steps for people over 50 with concerns about either issue. "Monitoring vitamin D levels and treating excess abdominal fat are essential measures to prevent premature death, especially after age 50," he said.
The study adds to a growing body of research suggesting that simple, measurable markers such as a waist tape measure and a blood test could help identify people at the highest risk of early death. The researchers say regular screening for both conditions, paired with treatment where needed, could be an important tool for extending healthy lifespan in older adults.
The new findings are 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 (搜索) leads to a loss of strength, which results in reduced walking speed, causing a loss of independence and greater dependence in daily activities," Alexandre explained. The research group has also found in a separate study that vitamin D deficiency increases the risk of cognitive decline.