Vitamin D, Pain, Depression, and Blood Pressure in Diabetic Women

Prescription strength doses of vitamin D improve highly prevalent co-morbidities among diabetic women, such as depression and pain, and also improve risk factors such as excess weight and high blood pressure, according to two poster presented at the American Diabetes Association 73^rd Scientific Sessions in Chicago, IL.

“Depression is much more common in people with diabetes, and the prevalence of cardiovascular disease is the highest in people who have both diabetes and depression,” said Sue M. Penckofer, PhD, RN, author of the study and a professor at the Loyola University School of Nursing in Maywood, IL.

As many as 25% of women with diabetes also have depression, and both depression and cardiovascular disease have been associated with low levels of vitamin D, added Penckofer, who presented poster 30-LB, “Vitamin D Supplementation Decreases Severity of Pain Symptoms among Women with Type 2 Diabetes and Comorbid Depression: Results from the Sunshine Study.”

“We know vitamin D can vasodilate the smooth muscle and act as a muscle relaxer, and decrease the blood pressure that way. Maybe it’s also functioning at the kidney level, perhaps altering the renin-angiotensin system, one of the hormones that cause hypertension,” she added.Penckofer and colleagues tested the effect of extra-high doses of vitamin D on women with diabetes by enrolling 46 type 2 diabetic women with depression and giving them weekly vitamin D supplementation of 50,000 international units for six months.

“You can’t buy that over-the-counter,” said Penckofer, who noted that vitamin D can increase patients’ calcium levels, and may cause hypercalcemia. “People should not take supplements without talking to their healthcare provider first,” she added.

The mean age of patients in the study was 54.6 years, and 54% were classified as white. The median baseline HbA1c was 6.8% and patients had had diabetes for a mean duration of 7.8 years.

The effect of vitamin D on depression was measured by the Center for Epidemiologic Studies Depression scale, which measures depression on a scale from 0 to 60, and the Physicians Health Questionnaire, a nine-question measuring tool.

At six months follow-up, depression decreased from a median of 26.8 to 12.2 on the 60-point scale, and the depression score as measured on the nine-question tool decreased from 11.5 to 5.2 (p < 0.001).

Blood pressure also decreased from 140.4 mm Hg to 132 mm Hg (p = 0.01). Additionally, weight decreased in the study participants, from 226.1 pounds to 223.6 pounds at six months follow-up (p < 0.05).

Penckofer and colleagues eliminated some potential confounders in the study. “We asked, ‘Could people have gotten better because they went on medication for depression?’ It turns out they did not. At baseline, 26% were on anti-depression medication, and at the end of the study, the number was 28%. Then I went and looked at their blood pressure medications. At baseline, 74% were on blood pressure medication, but at the end of the study, 76% were,” she said.

The researchers used the same study population to examine the effect of vitamin D on pain severity. Improvements were consistent in a range of factors, Penckofer said. At the outset of the trial, 97% of women stated they had lack of energy, but after vitamin D supplementation, only 76% said that was true. For fatigue, the before and after numbers were 91% and 70%, Penckofer said. Additionally, prior to the vitamin D study, 94% of diabetic women complained of moodiness, but afterward, the number had decreased to 62%. And before the study, 88% of participants said they had trouble concentrating, compared to only 50% after vitamin D supplementation, Penckofer noted.

The researchers theorize that vitamin D may work the same way as anti-depressant medication. “SSRIs work on receptors in brain; what if one of those antidepressant medications is trying to alter the way vitamin D receptor works?” Penckofer said.

The team of researchers will begin a new four-year study with 180 women in October, some of whom will get a high dose of vitamin D, while another arm gets a low dose. The study will track all the antidepressant medications used by participants. Penckofer and colleagues were recently awarded a grant of almost $1.5 million from the Institutes of Health to continue this research.