While people who are obese might be aware they have an elevated chance of having to fund diabetes treatment through international private medical insurance policies, a new study has shown overweight people with a lack of vitamin D have an even greater risk of developing the condition.
Research published in the journal Diabetes Care found individuals with both risk factors are more likely to develop insulin resistance than those with just one of the health problems.
"Vitamin D insufficiency and obesity are individual risk factors for insulin resistance and diabetes," Drexel School of Public Health doctoral candidate in epidemiology Shaum Kabadi explained.
A study at the university found people who were obese but who had normal vitamin D levels were 20 times more likely to be resistant to insulin than that seen by the average participant in the investigation.
However, those with obesity alongside low levels of the vitamin were 32 times more at risk of having insulin resistance than the general population.
This is a major risk factor for the development of type 2 diabetes, which occurs when a person cannot effectively convert glucose in their blood into energy.
The research is the first performed into the link between diabetes risk for obese men and women and levels of vitamin D that has used a representational and large sample of adults.
It was limited in the that data was reported from a single point in time, so scientists were unable to tell the cause-and-effect relationship between being overweight, vitamin D levels and insulin resistance.
Humans store vitamin D in their adipose fat tissues, with overweight individuals less likely to have high levels of the substance in their serum.
Deficiency of this vitamin is linked to a number of other health conditions as well as diabetes, including stroke, dementia, depression and other cardiovascular ailments.
Further research could determine if supplements of vitamin D can lessen the likelihood of a person becoming resistant to insulin, which the international healthcare specialists noted would be a practical and inexpensive way to prevent obese people from developing diabetes.
"It's not clear whether obesity itself causes a low vitamin D level or if it's the other way around," associate professor in the Drexel University School of Public Health and senior study author Dr Longjian Liu admitted.