Lack of vitamin D may increase diabetes risk
Here’s an addition to the long list of potential health benefits associated with vitamin D: if you don’t get enough of it, you may face an increased risk of developing type 2 diabetes.
Vitamin D has made quite a name for itself: it strengthens our bones and our immune system, it’s recommended in the treatment of several diseases and can even increase our lifespan.
But now Danish scientists suggest another potential health benefit of vitamin D: it may reduce the risk of developing diabetes.
"When we adjusted for other factors, we observed that people with very low levels of vitamin D in their blood had a 65 percent greater risk of developing type 2 diabetes than those with high vitamin D levels," says Lotte Husemoen, PhD, who’s a senior researcher in epidemiology at the Research Centre for Prevention and Health at Glostrup Hospital, Denmark.
She is the first author of the study, which has just been published in the journal Diabetes Care.
A comprehensive project
When we adjusted for other factors, we observed that people with very low levels of vitamin D in their blood had a 65 percent greater risk of developing type 2 diabetes than those with high vitamin D levels.
The new findings are based on two health studies of 4,296 men and women aged between 30 and 60.
They were first asked to fill in a questionnaire covering everything from exercise to smoking habits. They were then examined physically from one end to the other.
The researchers also measured the vitamin D levels in their blood, and performed a blood test to determine whether the participants were already suffering from type 2 diabetes. Those who did were not included in the study.
After the second medical examination of the many participants, the researchers reached the provisional conclusion that people with low vitamin D levels in the blood were twice as likely to develop type 2 diabetes as those with high vitamin D levels.
Statistical analysis adjusted for other confounding factors
The sun helps us produce vitamin D. But the sun, like so many other things, should be enjoyed in moderation.
While you’re busy trying to avoid type 2 diabetes, you could develop skin cancer if you overdo your sunbathing.
Source: Lotte Husemoen
Knowing that an unhealthy lifestyle including obesity, physical inactivity and an unhealthy diet can also influence the development of type 2 diabetes as well as the vitamin D level, the scientists also ran their data through a statistical software program, thus controlling for these and other risk factors.
Even after our statistical analysis, we observed an increased risk, though this time ‘only’ by 65 percent,” says Husemoen.
However, this statistical analysis made the result more uncertain, i.e. no longer statistically significant.
Measurements of insulin and glucose support the results
The researchers did, however, further examine this by measuring changes in insulin and glucose levels in the participants between the two health examinations.
Other studies have also pointed to a link between vitamin D deficiency and type 2 diabetes.
But Husemoen’s study is one of the the first in which the participants not only filled in a questionnaire about diabetes, but also had blood test taken, which gave a clear indication of whether or not they had the disease.
Source: Lotte Husemoen
These measurements support the results from the other data – that low vitamin D levels in the blood coincide with insulin and glucose levels changing for the worse. This indicates that a low vitamin D level influences markers of diabetes risk.
These measurements made the researchers more confident about their conclusion, says Husemoen:
“Our studies of glucose and insulin, which are markers of type 2 diabetes, were statistically significant even after controlling for other risk factors, which means that we have sufficient statistical confidence to say that these results are probably not random.”
Further studies needed to confirm the results
Husemoen believes that the only way we can be absolutely sure of what influence vitamin D has on the development of diabetes is by conducting a randomised study in which one group receives treatment, in this case vitamin D, while a control group does not receive treatment.
But such studies are expensive, which is why scientists usually start out with the type of study conducted by Husemoen and her colleagues in search for hypotheses that can be elaborated upon in further studies. And that appears to be the case with this study.
As things stand, most signs indicate that instead of being glued to your sofa, you should get out into the sunshine and get your daily fix of vitamin D if you want to lower the risk of developing type 2 diabetes.
Read the Danish version of this article at videnskab.dk
Translated by: Dann Vinther
- Serum 25(OH)D and Type 2 Diabetes Association in a General Population’; Diabetes Care; doi: 10.2337/dc11-1309