Ultraviolet Light And Vitamin D In Subjects With Fat Malabsorption Or After Gastric Bypass Surgery

Given that vitamin D is absorbed in the proximal small intestine, it is believed that
vitamin D deficiency in people with a fat malabsorption syndrome may be due to decreased
absorption of vitamin D. All diseases of the small bowel can cause fat malabsorption. These
fat malabsorption syndromes include Crohn's disease, ulcerative colitis, or cystic fibrosis
among others (1,2) and affect the amount of nutrients and fat absorbed by the
gastrointestinal tract.

Gastric bypass surgery is indicated for the surgical treatment of morbid obesity by making
the stomach smaller and allowing food to bypass proximal part of the small intestine, where
many minerals and vitamins are most absorbed. Food (and calorie) intake is dramatically
reduced because of the new small stomach. Many patients who have bypass surgery develop
nutritional deficiencies because they do not adhere to their post-operative guidelines
concerning the need for nutritional supplements. Malabsorptive operations like gastric
bypass surgery pose a particular risk for multiple nutritional deficiencies, including
vitamin D malabsorption. (3) Vitamin D is ingested in the diet, from supplements, as well as
synthesized naturally in the skin following UVB irradiation from the sun. As sunlight enters
the atmosphere, all radiation below 290 nm is absorbed by the stratospheric ozone layer.
Radiation between 290 and 315 nm is responsible for converting 7-dihydrocholesterol
(provitamin D3) in the epidermis and dermis to previtamin D3. Once formed, previtamin D3
undergoes a thermally induced isomerization to vitamin D3. Vitamin D3 enters the circulation
and is metabolized in the liver to 25-hydroxyvitamin D3 [25(OH)D] and then in the kidney to
1,25-dihydroxyvitamin D3 [1,25(OH)2D] by the 25-hydroxyvitamin D3-1á-hydroxylase [1á-OHase].
25(OH)D is the major circulating form of vitamin D and is routinely measured in the blood to
determine the vitamin D status of a patient.

The amount of vitamin D produced from winter sunlight and dietary sources will negligibly
raise blood 25-hydroxy vitamin D levels. People living in areas that receive less sunlight
have lower circulating 25-hydroxyD (the major circulating form used to measure vitamin D
status) levels. Vitamin D deficiency (defined as a serum 25(OH)D level < 20 ng/ml) in the
general population is treated with oral supplementation of vitamin D at a dose of 50,000 IU
given once weekly for eight weeks. (1) However from clinical experiences, oral
supplementation has limited efficacy in vitamin D deficiency patients with malabsorption
syndromes likely due to the inability to efficiently absorb vitamin D. *(1-3) A variety of
UV light sources have been developed and sold as in-home tanning devices and to produce
vitamin D in reptiles. In a pilot study, the investigators have observed that 5 out of 8
subjects had significant increased circulating 25(OH)D after exposure to a Sperti® lamp for
24 weeks. However, the possibility of correcting vitamin D deficiency by the skin exposure
to artificial source of UVB radiation in patients with fat malabsorption has not been
studied.

The first aim of this study will be to evaluate the efficacy of an FDA approved artificial
source of UVB radiation (Sperti® lamp) in raising serum 25(OH)D levels in patients with fat
malabsorption due to Crohn's disease, ulcerative colitis, or cystic fibrosis or gastric
bypass surgery and other causes. The second aim of the study is to compare the rise in serum
25(OH)D over the repeated measures in this study in patients with the 4 different skin types
(types II-V).

The device that the investigators used in this study was originally designed for tanning.
From our pilot study H23521 the investigators observed that much longer times were needed to
increase the production of vitamin D. As can be seen in Figure 1, our healthy adults exposed
to up to 10 minutes to the Sperti lamp showed significant increases in serum 25 (OH)D levels
in the subjects studied. The investigators found that 5 of the 8 subjects showed significant
increases in 25(OH)D. Those with skin type IV and V demonstrated minimal responses due to
the sunscreening effect of their skin pigment (Fig 2). This demonstrates that skin types IV
and V may require longer exposure times to achieve the 0.75 MED dose and raise the serum
25(OH)D level. However, during this pilot study, the investigators did not observe any
untoward side effects (such as skin redness) associated with exposure to UVB light with
longer exposure times.

Inclusion Criteria:

1. Men and women, age 18 years or older with skin types 2,3,4 and 5.

2. The patient has an established diagnosis of conditions that have been associated with
fat malabsorption due to bowel disease (Crohn's disease, ulcerative colitis, or
cystic fibrosis), or history of gastric bypass surgery that at least 3 months
post-surgery with no continuing complications.

3. The patient is able to understand the information provided to them and who have given
written informed consent to the study.

4. The patient is able to understand and complete self-administered questionnaires.

5. The patient is able and willing to follow study procedures.

6. If female, the patient is either postmenopausal for at least one year, surgically
incapable of childbearing, or effectively practicing an acceptable method of
contraception (oral or parenteral hormonal contraceptive; intrauterine device;
barrier and spermicide or abstinence). Patients must agree to use adequate
contraception during the study.

Exclusion Criteria:

1. Treatment with pharmacologic doses of vitamin D3, vitamin D3 metabolites or
analogues, ongoing or within 30 days prior the start of the study.

2. Pregnancy and lactation.

3. History of underlying photosensitivity.

4. Patients with a history of chronic kidney disease or severe liver dysfunction that
would alter their calcium and vitamin D metabolism.

5. Subjects with skin type I (who will develop skin burns after UVB exposure).

6. Use of medications that cause a photosensitivity reaction including
hydrochlorothiazide or tetracycline.

7. History of skin cancer .

8. Patients with history of hypocalcemia (calcium <8.6mg%), hypercalcemia (calcium
>10.4mg%).

9. Taking drugs known to influence vitamin D metabolism, such as glucocorticoids and
antiseizure medications.

10. Patients with a history of severe, progressive, and/or uncontrolled renal, hepatic,
hematological, gastrointestinal, endocrine, pulmonary, cardiac, neurological, or
cerebral disease within 3 months.

11. Patients who have travelled through a warm sunny climate without using sunscreen
within 1 month of the beginning of the study, or plan to do so during the study
period.

12. Patients who taking any medications which causes skin sensitivity to sunlight
(certain antibiotics; retin-A cream used for acne).