Vitamin D and Type 2 Diabetes Study

The goal of the Vitamin D and type 2 diabetes (D2d) study is to determine if vitamin D
supplementation works to delay the onset of type 2 diabetes in people at risk for the disease
and to gain a better understand how vitamin D affects glucose (sugar) metabolism. Researchers
at US sites will enroll people with pre-diabetes (people who have higher than normal blood
glucose level but not high enough to meet the diagnosis of diabetes). The study will enroll
participants over approximately 2 years and participants will be followed for approximately 3
years. Participants will receive either Vitamin D or a placebo by chance. Participants will
take 1 pill a day for the duration of the study.

Inclusion Criteria:

1. Pre-diabetes ("at increased risk for diabetes") defined by meeting 2-out-of-3 of the
following glycemic criteria at the baseline visit:

1. Fasting plasma glucose (FPG) 100-125 mg/dL

2. 2-hour plasma glucose (2hPG) 140-199 mg/dL

3. Hemoglobin A1c (HbA1c) 5.7-6.4%

2. Age ≥ 30 years .(≥25 years for people of the following races: American-Indian, Alaska
Native, Native Hawaiian or Other Pacific Islander).

3. Body Mass Index 22.5 to 42 kg/m2

4. Provision of signed and dated written informed consent prior to any study procedures.

Major Exclusion Criteria:

1. Diabetes based on either of the following criteria:

1. History (past 1 year) of hypoglycemic pharmacotherapy (oral or injectable
medication approved by the FDA for type 2 diabetes), used for any condition (e.g.
pre-diabetes, diabetes, polycystic ovarian syndrome.

2. Meeting the diagnosis criteria for diabetes

2. History (past 3 years) of hyperparathyroidism, nephrolithiasis or hypercalcemia.

3. Pregnancy (past 1 year by report or positive pregnancy test at screening), intent to
become pregnant in the next 4 years or unprotected intercourse. History of gestational
diabetes is not an exclusion criterion.

4. Currently breastfeeding.