Magazine article Clinical Psychiatry News

Vitamin D Deficiency

Magazine article Clinical Psychiatry News

Vitamin D Deficiency

Article excerpt

The Problem

You are working in a correctional setting and start a new assignment in administrative segregation (jail within a prison). Many inmate-patients serve months to years in this setting and receive 1 hour of yard time per day. Many simply hole up and never go outside. You wonder if these inmates' vitamin D levels are adequate.

The Question

What is an adequate serum vitamin D level, and what are the health sequelae, both medical and psychiatric, to low levels of vitamin D?

The Analysis

We first searched the Cochrane Database of Systematic Reviews ( and found no reviews on this topic. We then searched Medline, combining "vitamin D" and "deficiency or psych$." We also located a comprehensive Web site:

The Evidence

To find out what constitutes adequate vitamin D levels and what the medical consequences of low levels are, we turned to a recent review article by Dr. Michael F. Holick (N. Engl. J. Med. 2007;357:266-81). To answer the psychiatric part of the question, we reviewed original articles obtained from the sources cited above.

Vitamin D from the skin and diet is hepatically converted to 25-hydroxyvitamin D (25-OH D), which is used to determine an individual's vitamin D status. The 25-OH D is converted in the kidneys by 25-OH D-1-hydroxylase to the active form 1,25-dihydroxyvitamin D (1,25-OH D). Renal production of 1,25-OH D is regulated by parathyroid hormone (PTH), calcium, and phosphorus levels. With the discovery that most cells in the body have vitamin D receptors, the varied functions of this vitamin have become better understood.

Levels of 25-OH D are inversely proportional to PTH until 25-OH D levels reach 30-40 ng/mL. (Currently, most laboratories define deficiency as a 25-OH D level less than 20 ng/mL.) Researchers have shown intestinal calcium absorption to increase by 45%-65% in women when 25-OH D levels went from 20 to 32 ng/mL. Others have shown that more than 50% of postmenopausal women with osteoporosis had 25-OH D levels of less than 30 ng/mL. One study showed maximum bone density in men and women when the 25-OH D level was 40 ng/mL or greater. At levels less than 30 ng/mL, there was an increase in PTH (which stimulates the production of osteoclasts).

Another study showed that 93% of 150 patients who presented with muscle aches and bone pain and had diagnoses such as fibromyalgia or chronic fatigue had 25-OH D levels less than 20 ng/mL. Pooled data from multiple studies have shown that giving elderly men and women vitamin [D.sub.3] (700-800 IU) and calcium (500-1000 mg per day, or sufficient to maintain 25-OH D levels above 40 ng/mL) significantly reduces the risk of hip and nonvertebral fractures.

Skeletal muscle has vitamin D receptors. Performance speed and proximal muscle strength (with a subsequent decrease in falls) has been shown to increase as 25-OH D levels rise to greater than 40 ng/mL. Brain, prostate, breast, colon, and immune tissue also have vitamin D receptors. Epidemiological studies have shown that 25-OH D levels of less than 20 ng/mL are associated with a 30%-50% increased risk of colon, prostate, and breast cancer.

A large cohort study (32,826 participants) showed an inverse association between 25-OH D and the odds ratio for colorectal cancer: The odds ratio was 1.0 at 16.2 ng/mL and 0.53 at 39.9 ng/mL. Data for 980 women showed that the highest level of vitamin D intake, compared with the lowest, was associated with a 50% lower risk of breast cancer. Other studies have shown a 41% lower risk of multiple sclerosis for the higher level when comparing 25-OH D levels of 44 ng/mL and 24 ng/mL. …

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