Combination of abdominal obesity and vitamin D deficiency more than doubles the risk of death in people over 50

A study involving over 5,500 individuals indicates that hormone level monitoring and weight control are essential measures to avoid premature death.

By Maria Fernanda Ziegler  |  Agência FAPESP – A study of more than 5,500 people over the age of 50 has raised a red flag: it found that people with abdominal obesity and vitamin D deficiency have a 123% higher risk of death than those without these conditions. Results of the study published in the journal Diabetes, Obesity and Metabolism indicate that although each condition is dangerous on its own, they multiply the risk of mortality when present together.

“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.

Conducted in collaboration with the University College London (UCL) in the United Kingdom and funded by FAPESP, the research observed 5,520 individuals aged 50 and older over the course of six years. The participants were part of the English Longitudinal Study of Ageing (ELSA), one of the world’s largest aging studies.

Sampled data showed that vitamin D deficiency (levels below 30 nmol/L) alone poses a greater risk than abdominal obesity alone, which is defined as an abdominal circumference greater than 102 centimeters for men and 88 centimeters for women. Having abdominal obesity alone increases the risk of death by 47%, while vitamin D deficiency alone can raise this risk by up to 91%. The study showed that when the two conditions occur together, the risk of death more than doubles.

According to Alexandre, the two conditions create a vicious cycle. Abdominal fat “sequesters” circulating vitamin D and stores it in adipocytes (fat cells), preventing the vitamin from reaching 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.

Another important factor is that obese individuals have lower expression of the enzymes necessary for vitamin D metabolism, which further reduces its availability. “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.

Added to this is the fact that aging is naturally marked by a process known as 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,” he stresses.

Cascade effect

This study is the latest in a series investigating the role of vitamin D in 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 (read more at agencia.fapesp.br/56984).

Additionally, another study by the group revealed that vitamin D deficiency increases the 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.

The article “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” can be read at dom-pubs.pericles-prod.literatumonline.com/doi/10.1111/dom.70839.