Excess abdominal fat combined with vitamin D deficiency increases the risk of premature death

It is well known that excess abdominal fat increases the risk of chronic inflammation, cardiovascular disease, type 2 diabetes, and high blood pressure. The combination of excess abdominal fat and vitamin D deficiency appears to further increase the risk of chronic disease and premature death in people over the age of 50, as shown by a study published in Diabetes, Obesity and Metabolism. Here, the researchers describe how vitamin D protects against premature death. It may therefore be beneficial for your health to check whether your waist circumference is within an appropriate range and whether your blood vitamin D level is optimal throughout the year.

Excess abdominal fat is referred to as abdominal obesity and is a component of metabolic syndrome, which is a precursor to type 2 diabetes. In addition, a person can be what is sometimes referred to as “thin on the outside, fat on the inside,” (TOFI) meaning that their BMI is within the normal range but they have a relatively high fat mass compared with muscle mass. At the same time that the risk of abdominal obesity increases with age, the risk of vitamin D deficiency also does. Studies have shown an inverse relationship between increasing abdominal obesity and declining levels of vitamin D in the blood.
However, there has been a lack of studies clarifying whether the combination of abdominal obesity and vitamin D deficiency affects the health of older people, and this was therefore what the researchers wanted to investigate.

Excess abdominal fat and vitamin D deficiency are a dangerous combination

The new study included 4,520 participants aged 50 and older, all of whom were recruited from a population study called ELSA. Abdominal obesity was defined as a waist circumference of more than 88 cm for women and more than 102 cm for men. Blood vitamin D levels were categorized as “sufficient” (above 50 nmol/L), “insufficient” (30–50 nmol/L), or “deficient” (below 30 nmol/L). The participants were then divided into six different groups according to waist circumference and blood vitamin D levels. After the researchers adjusted for various confounding factors such as physical activity, smoking, and alcohol consumption, the study revealed the following:

• The combination of abdominal obesity and vitamin D deficiency was associated with a 129% higher risk of premature death
• Vitamin D deficiency alone increased the risk of premature death by 91%
• Abdominal obesity alone increased the risk of premature death by 47%
• Abdominal fat cells store vitamin D without releasing it into the bloodstream and to organs that need the vitamin
• Low vitamin D levels impair the immune system's ability to control inappropriate chronic inflammation, which creates conditions conducive to most chronic diseases

The researchers therefore conclude that the combination of abdominal obesity and vitamin D deficiency further increases the risk of premature death in older people. It is therefore advisable to address both factors early through weight loss to reduce waist circumference and appropriate supplementation to optimize blood vitamin D levels throughout the year and throughout life.

Why is abdominal obesity so harmful to health?

Abdominal obesity is particularly harmful because it primarily consists of so-called visceral fat, which is located around the internal organs. These biologically active visceral fat cells release a range of hormones and pro-inflammatory substances into the bloodstream, increasing the risk of insulin resistance, chronic inflammation, oxidative stress, high blood pressure, type 2 diabetes, cardiovascular disease, and other lifestyle-related diseases. As mentioned above, abdominal fat cells also store vitamin D without releasing it into the bloodstream when cells and tissues need it.

There are several reasons why older and overweight people are more likely to be deficient in active vitamin D

Summer sunlight is the most important source of vitamin D, and we initially produce a precursor to vitamin D in the skin from cholesterol. The vitamin is then converted by enzymes in the liver into the form that is measured in the blood and stored in the body. When vitamin D is needed for its many functions, it is released from these stores and activated by other enzymes in the kidneys, immune cells, and elsewhere.
However, the body's ability to produce vitamin D declines with age, both because the skin becomes thinner and because the enzymatic processes in the liver and kidneys tend to become sluggish.
In addition, people with abdominal obesity and metabolic syndrome have greater difficulty converting and activating vitamin D because of reduced activity of the enzymes involved in the body's vitamin D metabolism. This means that older people with abdominal obesity need more vitamin D than the rest of the population.
It is of course beneficial to produce vitamin D from sunlight during the summer months and to take the supplements recommended by health authorities (10–20 micrograms per day). Still, there is no guarantee that these supplements will optimize blood vitamin D levels, as the ability to produce and utilize the vitamin varies considerably from person to person. Therefore, many older and overweight people may benefit from having their blood vitamin D levels measured, which should ideally be above 75 nmol/L.
Stronger supplements containing up to 100 micrograms are also available on the market, which according to EFSA is the upper safe limit.

References:

Joyce da Silva Milliati et al. Does the combination of abdominal Obesity and vitamin D Deficiency Increase the Risk of Death in Individuals Ages 50 or older? Evidence from the ELSA Study. Diabetes, Obesity and Metabolism. 2026

Fundacâo de Amparo a Pesquisa do Estado de Säo Paulo. This Common vitamin deficiency becomes far more dangerous when paired with belly fat. ScienceDaily 2026