Please select the eligibility criteria that correspond to the clinical trial below.
Title: Vitamin D Dose-Response Study to Establish Dietary Requirements in Infants
Brief Summary: The research team is comprised of an expert nutrition scientist and a pediatrician with expertise in endocrinology. Both have world-class experience in assessing bone mass in infancy. Together they have designed a study to determine how much dietary vitamin D is needed to optimize health in infants. This is important since many infants are born with vitamin D deficiency. At present the dosage of vitamin D that is optimal for infant health is unclear and recent research suggests that vitamin D status very early in life has long lasting effects on bone mass and other health issues. Therefore, in a group of healthy infants, this research team will test which dosage of vitamin D is needed to achieve optimal vitamin D status. Optimal vitamin D status will be based on growth, biomarkers of vitamin D and bone status in blood and also general health. The infants will all be breastfed and begin the study at about 2 weeks of age. At 3 months intervals over the first year of life, each infant will be measured for growth, duration of breastfeeding and supplement use plus have a bone density scan to determine changes in bone growth. The data will be helpful to guide health care professionals in providing the best care possible for their infants. It will also be important to the health of populations since dietary recommendations for vitamin D are used to guide fortification of foods and development of evidence based policy around nutrient recommendations and their implementation.


Options:
A: Inclusion Criteria:

* Adult (\>18 years)
* No more than 18 weeks gestation
* In good general health
* Low risk pregnancy
* Not consuming \>10 mcg/d vitamin D from supplements

Exclusion Criteria:

* Current smokers
* Diagnosed hypertension
* Known high-risk pregnancy
* Diagnosed medical illness including diabetes mellitus (Types 1 \& 2), chronic kidney disease or gastro-intestinal diseases or any illness known to interfere with calcium metabolism (e.g. sarcoidosis).
* Consumption of medications known to interfere with vitamin D metabolism
* Consumption of vitamin D (≥ 10 µg/day) or calcium (≥ 650 mg/d) supplements prior to randomization
B: Inclusion criteria:

1. 28 0/7-36 6/7 weeks gestational age (GA) at birth;
2. family identifies the child as black or African American;
3. \< 28 days of supplemental oxygen (subsequent oxygen therapy for \< 72 hrs for a brief subsequent illness or surgery will be allowed);
4. admitted to a participating site NICU, special care nursery, transitional care nursery, or well-baby nursery as a neonate; and
5. \< 40 weeks corrected GA at enrollment.

Exclusion criteria:

1. BPD (\> 28 days of supplemental oxygen);
2. pre-existing diagnosis of moderate to severe osteopenia of prematurity and/or alkaline phosphatase \> 700;
3. history of fracture;
4. gastrointestinal surgery, including for NEC;
5. known gastrointestinal malabsorption;
6. major congenital anomaly;
7. congenital pulmonary or airway disorder (e.g., cystic fibrosis, tracheomalacia, swallowing disorder, bronchopulmonary sequestration);
8. documented wheezing or stridor prior to enrollment;
9. previous vit. D supplementation with \> 400 IU/day;
10. family plans to move more than 60 miles from CWRU or other pre-defined radius at other sites;
11. baseline hypo- or hypercalcemia, hypo- or hyperphosphatemia; and
12. baseline 25(OH) D level \< 10 ng/ml.
C: Inclusion Criteria:

* Healthy, singleton term infants of appropriate for gestational age, according to Centers for Disease Control (CDC) growth charts based on weight at birth between 5th and 95th percentiles for sex
* Born to healthy breastfeeding women
* Exclusively breast fed infants from birth, according to WHO definition: breast milk, expressed breast milk, vitamins, minerals and medicine but not including water, breast milk substitutes, other liquids and solid foods.

Exclusion Criteria:

* Infants of mothers with a history of gestational diabetes or hypertension in pregnancy; chronic alcohol use; malabsorption syndromes (Celiac disease, Crohn's, etc.), due to malabsorption of fat soluble vitamins
* Mothers taking any medications that can affect vitamin D metabolism (anticonvulsants and corticosteroids)
* Mothers taking ≥ 2,000 IU/d of vitamin D from supplementation
D: Inclusion Criteria:

* Healthy singleton term born infants of appropriate size for gestational age (AGA) according to the Centers for Disease Control growth charts based on weight at birth between the 5th and 95th percentiles for sex; and born to healthy breastfeeding women. This allows us to assess growth and bone mineral accretion without bias of intrauterine growth restriction.

Exclusion Criteria:

* Infants of mothers with history of gestational diabetes or hypertension in pregnancy; chronic alcohol use; malabsorption syndromes due to malabsorption of vitamin D (celiac disease, Crohn's etc.); and multiple births.
* Should any exclusion criteria be identified after recruitment, the infant will be excluded from the main analyzes, but followed in a separate arm as intent-to-treat.

Answer: D