Effect of Vitamin D and Calcium on Genes in the Colon
Condition: Colorectal Polyps; Colorectal Adenoma; Adenocarcinoma
MeSH terms: Adenoma
Study type: Interventional
Phase: Phase 1

Summary: 
      The researchers are involved in a research program to understand how vitamin D and calcium in
      the diet or as supplements may lower the risk of colorectal polyps and cancer. To that end,
      the researchers are conducting a study of vitamin D supplementation in which volunteer
      subjects are provided a Western style diet for 2 separate 4 week periods at the Rockefeller
      University Hospital. During one of these 4 week inpatient periods, subjects receive calcium
      supplements and during the other 4 week inpatient period they receive a placebo tablet. The
      researchers determine changes within the colon as a result of supplementing the vitamin D in
      the presence of high and low calcium. A more detailed description of the study is provided
      below.
    

Detailed description: 
      Study subjects participate for about 3 months. During this time, there is one outpatient
      visit, a 4 week inpatient period, a 4 week outpatient period known as a wash out period and
      finally another 4 week inpatient period. During the inpatient periods, the Rockefeller
      University Hospital (RUH) becomes your home. The subject must sleep here every night and
      consume all the food provided. During the screening visit, blood and urine samples will be
      taken and an EKG (electrocardiogram) and a complete physical exam will be done. After
      enrollment into the study, the first 4 week inpatient period begins. You may continue to go
      to work or do other activities as long as you eat the diet provided and sleep at the
      Rockefeller University Hospital. You must eat everything that we give you and you may not
      substitute or supplement the diet in any way. During each 4 week stay at the Rockefeller
      University Hospital, there will be three flexible sigmoidoscopies done and biopsies taken of
      the mucosal lining of the colorectum. This procedure is painless and takes about 5 minutes.
      In addition, blood samples will be taken every few days for follow-up and research, and two
      24 hour urine samples will be done on separate days during the hospitalization. Vital signs
      are measured every day and your weight will be measured three times per week. During the four
      week wash out period, the subject will return to their home, go about their normal activities
      and consume their normal diet. The subject will return to the Rockefeller University Hospital
      for the second 4 week inpatient period. The procedures and laboratory tests are the same
      during the second inpatient period. The study concludes with the subjects' discharge from the
      RUH.
    

Intervention name(s): placebo and Calcitriol; Calcium and Calcitriol
Intervention type(s): Drug; Drug
Intervention description(s): Placebo tablets twice daily together with an oral tablet of 1, 25 dihydroxy vitamin D3 (Calcitriol); Calcium twice daily together with an oral tablet of 1, 25 dihydroxy vitamin D3 (Calcitriol)
Intervention MeSH terms: Calcitriol; Calcium
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary purpose: Prevention