Older adults with both low vitamin D levels and abdominal obesity faced a 123% higher risk of death over six years, while either condition alone was also associated with increased mortality, according to a study of more than 5,500 people.
By yourNEWS Media Newsroom
Older adults who have both low vitamin D levels and excess abdominal fat may face substantially higher mortality risks than people with neither condition, according to a study examining more than 5,500 adults aged 50 and older.
Researchers at the Federal University of São Carlos in Brazil analyzed health data from 5,520 participants in the English Longitudinal Study of Ageing and found that the combination of abdominal obesity and low vitamin D was associated with a 123% higher risk of death during approximately six years of follow-up.
The findings were published in Diabetes, Obesity and Metabolism.
Participants who had neither abdominal obesity nor low vitamin D experienced the lowest mortality rate.
The risk increased when either factor was present independently. Participants with a high waist circumference but adequate vitamin D levels had a 47% higher mortality risk, while those with low vitamin D but without abdominal obesity had a 91% higher risk.
The largest increase was observed among people who had both conditions.
Lead researcher Tiago Silva Alexandre said assessing vitamin D status and waist circumference together could provide clinicians with a more complete picture of health risk in older adults than evaluating either measurement by itself.
The findings add to research examining how body composition, nutritional status and metabolic health interact as people age.
Researchers Followed More Than 5,500 Adults for Six Years
The researchers used information from the English Longitudinal Study of Ageing, a continuing study that monitors health, social and economic conditions among adults in England as they grow older.
Participants included in the analysis were at least 50 years old.
Researchers measured waist circumference and serum vitamin D concentrations when participants entered the analysis and then tracked mortality during the following six years.
Approximately 1,200 of the 5,520 participants died during the follow-up period.
The research team statistically adjusted its analysis for age, sex and other factors that could influence mortality. The associations between abdominal obesity, low vitamin D and death remained after those adjustments.
Because the study was observational, however, it cannot establish that low vitamin D or abdominal obesity directly caused the deaths.
Instead, it demonstrates that the two characteristics were associated with higher mortality rates in the population studied.
Earlier research has separately connected vitamin D deficiency with increased mortality.
A 2008 study by Melamed and colleagues published in the Archives of Internal Medicine, and later cited in Samantha Heller’s “Get Smart: Samantha Heller’s Nutrition Prescription for Boosting Brain Power and Optimizing Total Body Health,” reported a relationship between vitamin D deficiency and mortality in the general population.
The newer research extends that discussion by examining what happens when low vitamin D occurs alongside abdominal obesity.
Abdominal Fat Can Signal Broader Metabolic Problems
Waist circumference is often used as a practical indicator of abdominal adiposity, particularly visceral fat that accumulates around internal organs.
That type of fat can carry different health implications from fat stored elsewhere in the body.
Metabolic syndrome, which frequently includes excess abdominal fat, has long been associated with increased risks of cardiovascular disease and premature death, according to “Bioactive Food as Dietary Interventions for Cardiovascular Disease” by Ronald Ross Watson.
Visceral fat is biologically active rather than simply functioning as stored energy.
It can release inflammatory substances known as adipokines, which may contribute to insulin resistance and chronic systemic inflammation.
Those metabolic disturbances can increase the likelihood of conditions including Type 2 diabetes and cardiovascular disease.
The findings suggest that the health effects associated with excess abdominal fat may become particularly important when combined with inadequate vitamin D status.
Researchers proposed several biological explanations for why the two factors could interact.
One involves the way vitamin D behaves in body fat.
Vitamin D is fat-soluble, meaning it can accumulate in adipose tissue. When a person carries substantial amounts of excess body fat, more vitamin D may become stored in fat cells and therefore less available in circulation for use by other tissues.
The study suggested that this reduced bioavailability could help explain why obesity and low measured vitamin D frequently occur together.
Vitamin D Functions Beyond Bone Health
Vitamin D is best known for its role in calcium absorption and bone health, but it also behaves like a hormone and participates in numerous physiological processes.
“Orthomolecular Nutrition for Everyone” by Helen Saul Case, Andrew Saul and Linus Pauling describes adequate vitamin D status as being associated with functions that include immune activity and metabolic regulation.
Dr. Sina McCullough and Joel Salatin similarly discussed vitamin D’s hormone-like role in metabolism, including its involvement in blood sugar regulation, during an interview with Health Ranger Mike Adams.
Researchers have therefore become increasingly interested in whether vitamin D deficiency is simply a marker of poor health or whether inadequate levels contribute directly to metabolic and cardiovascular problems.
The relationship can be difficult to separate because people with chronic illness, reduced mobility or obesity may be more likely to develop low vitamin D for reasons unrelated to a direct biological effect.
The Brazilian research team noted that abdominal fat and low vitamin D may reinforce one another.
Excess fat may reduce the amount of vitamin D available to the body, while metabolic dysfunction associated with obesity can contribute to chronic inflammation and other conditions related to poorer health outcomes.
The study could not determine whether changing either factor would necessarily reduce mortality.
Diet, Sunlight and Activity Can Affect Both Markers
Vitamin D status can be influenced by sunlight exposure, diet, supplements, age, skin characteristics, geographic location and other factors.
Darryl Edwards wrote in “Paleo from A to Z” that approximately 10 to 20 minutes of moderate sunlight on exposed skin several times per week can stimulate vitamin D production, although the amount produced varies widely depending on season, latitude, skin pigmentation and other circumstances.
The book also notes that vitamin D3 supplementation may be necessary for some people living in northern climates during winter months.
Foods naturally containing vitamin D include fatty fish such as salmon, sardines and mackerel.
Those foods also provide omega-3 fatty acids and have been discussed as part of dietary approaches aimed at supporting cardiovascular and metabolic health.
Physical activity and diets centered on minimally processed whole foods can meanwhile help people maintain healthier body composition and reduce excess abdominal fat.
Previous reporting has also examined vitamin D in connection with weight management.
One study involving women older than 50 found that participants who received 2,000 international units of vitamin D per day lost more weight and reduced their waist circumference more than participants receiving a placebo.
That finding does not establish vitamin D as a weight-loss treatment, but it has contributed to research examining relationships among vitamin D deficiency, obesity and metabolic health.
NaturalNews.com has also identified vitamin D among natural substances discussed in connection with abdominal-fat management.
Researchers in the current study did not recommend using vitamin D supplements as a substitute for medical evaluation or as a treatment for obesity.
Mortality Findings Fit Into Broader Obesity Research
Obesity remains a major public health concern because of its associations with cardiovascular disease, diabetes, certain cancers and other chronic conditions.
A 2013 report cited by Mercola.com discussed research estimating that nearly one in five U.S. deaths was associated with obesity.
The current findings suggest that waist circumference may provide additional information beyond body weight alone, particularly when combined with another readily measurable marker such as vitamin D.
Waist circumference is inexpensive and easy to measure, while serum vitamin D can be evaluated through routine blood testing.
That combination could potentially help identify older adults who warrant closer assessment for broader metabolic and nutritional risks.
Researchers cautioned that the study has important limitations.
Because it was observational, it cannot prove that improving vitamin D levels, reducing abdominal fat or addressing both simultaneously will reduce a person’s mortality risk.
Some health behaviors examined in the broader dataset were also self-reported, introducing the possibility of reporting errors or inaccuracies.
Other unmeasured factors could have contributed to the associations as well.
For example, chronic illness may reduce physical activity, increase abdominal fat and limit sunlight exposure, potentially producing low vitamin D while independently increasing mortality risk.
Researchers Call for Intervention Studies
The study team said future research should investigate whether intentionally improving vitamin D status and reducing abdominal obesity can translate into lower mortality.
Controlled clinical trials would be required to determine whether changing those markers directly changes health outcomes rather than simply identifying people who are already at greater risk.
For now, the findings suggest that looking at vitamin D and waist circumference together may provide useful information about the health of aging adults.
A person with only one of the factors had an elevated mortality risk in the study, but the combination produced the strongest association.
Compared with participants who had neither low vitamin D nor abdominal obesity, those with high waist circumference alone faced a 47% increase in mortality risk, those with low vitamin D alone faced a 91% increase, and those with both faced a 123% increase over the six-year study period.
The results do not establish a cause-and-effect relationship, but they highlight two relatively simple measurements that researchers say may help identify older adults with greater underlying health vulnerabilities.
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