My 24-year-old son has had type 1 for seven years. His HbA1c has always been between 5.7 and 6.3, except at the time the initial diagnosis was made. In January 2013, the then endocrinologist (at the Naomi Berrie Diabetes Center) included a blood test for his vitamin D level, along with the other annual tests he gets. It came back quite low at 15.8 (normal is 30 to 100). His vitamin D level was never tested before and now I am reading about a study that says there could be a link between low vitamin D levels and the development of type 1. I would hate to think that vitamin D supplements could have prevented this disease, but I cannot change the past. The doctor gave him prescription strength vitamin D supplements for a month and then told him to take over the counter vitamin D, which he sort of stopped doing. He returns to see the doctor next week, so hopefully this will be followed up. Can you please tell me the correlation between vitamin D levels and diabetes control/complications? Do adequate vitamin D levels impact diabetes? I am not sure why the doctor suddenly decided to check vitamin D levels six months ago, when it was never checked in the seven years since his diagnosis. I am confused about all of this. Please let me know about the importance of normal vitamin D levels and diabetes.

There is a lot of new information about vitamin D. To start with, it’s actually a hormone and misnamed a vitamin! You are correct also that there are some studies associating low levels of vitamin D and the development of diabetes, both type 1 and type 2. But, there is also some controversy over these studies since they are not so easy to interpret. Most of us believe that vitamin D acts in the body not only to strengthen bones and prevent osteopenia and osteoporosis but also in its hormone status to help the brain function, improve muscle function/strength, decreased risks of heart attack, blood pressure and lipid abnormalities and also decrease autoimmune and cancer risks. The last one is the most intriguing since autoimmune problems such as type 1 diabetes but also Hashimoto’s thyroiditis, lupus, MS, rheumatoid arthritis all may potentially be prevented or postponed – certainly decreased – if the vitamin D levels can be increased significantly. So, there are lots of reasons to worry about vitamin D. In our practice, we began looking at vitamin D levels about five years ago and were finding a lot of low values – and lots of osteopenia and osteoporosis in children and teenagers and not just elderly so it’s good that the levels were checked but not so good if he declines to treat these abnormalities since these are significant risks.

The other good news is that even a 10% reduction in heart, blood pressure, lipid, cancer, thyroid risks is significant and this is quite easy to do with inexpensive over-the-counter vitamin D supplements each day. Most of our patients seem to require about 4000 to 8000 IU of vitamin D3 as a daily supplement to get levels to target range. We usually track these levels two to three times a year to make sure that we are not giving too much or need a dose adjustment up or down accordingly. So, it is difficult to know why anyone would not want to consider this relatively inexpensive, safe and simple supplement. Levels need checking to make sure it’s neither too high nor too low a supplement, periodically. If the levels are low, then we also usually get a baseline bone density DXA scan (bone density scan) to see if any abnormalities already present and then followup accordingly.

SB
Additional comments from Dr. Jim Lane:

Vitamin D research has been hot. This is especially true for non-skeletal effects of vitamin D. There have been a number of preliminary studies looking at effects of vitamin D on cancer, diabetes, and other areas not traditionally thought to involve vitamin D. Most of what I have read in the literature is related to the development of type 2 diabetes. There is some thought that vitamin D may in some way make humans more insulin resistant. Since type 1 diabetes is caused by the immune system attacking the insulin-producing cells, any involvement with vitamin D would have to effect the immune system. These are preliminary studies and not considered to be found absolute truths in the type 1 diabetes field.

Vitamin D levels have gone down in society as we are less exposed to the sun. If you are not a dairy eater, especially vitamin D fortified milk, you may need vitamin D supplements to normalize your levels. This is a very common finding. Levels below 20 are thought to be deficient and levels above 30 are thought to be sufficient. There is a gray area for levels 20 to 30. Supplementation for your son is appropriate for levels below 20, such as he has.

JTL