Ultraviolet Light And Vitamin D In Subjects With Fat Malabsorption Or After Gastric Bypass Surgery
Condition: Vitamin D Deficiency; Gastrointestinal Diseases
MeSH terms: Gastrointestinal Diseases; Digestive System Diseases; Malabsorption Syndromes; Vitamin D Deficiency
Study type: Interventional

Summary: 
      Patients with fat malabsorption due to Crohn's disease, ulcerative colitis, or other causes
      including cystic fibrosis, among others, or who have undergone gastric bypass have increased
      incidence of vitamin D deficiency relative to the general population. Given that vitamin D is
      fat soluble and absorbed in the proximal small intestine, it has been documented that vitamin
      D deficiency in people with a fat malabsorption syndrome is due to decreased absorption of
      vitamin D.

      The amount of vitamin D produced from winter sunlight (in Boston, MA) and dietary sources
      will negligibly raise blood vitamin D levels in these patients, and oral vitamin D
      supplementation may have limited efficacy due to malabsorption. A variety of UV light sources
      have been developed and sold as in-home tanning devices and to produce vitamin D in reptiles.
      The efficacy of correcting vitamin D deficiency by the skin exposure to an artificial source
      of UVB radiation in patients with fat malabsorption syndromes (Crohn's disease, ulcerative
      colitis, or cystic fibrosis) or after gastric bypass surgery has not been studied. The
      investigators have conducted a pilot study in healthy adults that demonstrated that exposure
      to the lamp raised the blood level of 25-hydroxyvitamin D with no side effects. The main
      purpose of this study is to evaluate the effect of the FDA approved artificial source of
      ultraviolet (UVB) radiation (Sperti® lamp) in improving vitamin D status in patients with fat
      malabsorption syndromes and patients who have undergone roux-en-Y gastric bypass surgery.
    

Detailed description: 
      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.
    

Intervention name(s): Sperti Lamp
Intervention type(s): Device
Intervention description(s): UV light exposure 3 times per week for 12 weeks
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Other