Nutritional Outcomes After Vitamin A Supplementation in Subjects With SCD

Suboptimal vitamin A (vit A) status is prevalent in children with type SS sickle cell disease
(SCD-SS) and associated with hospitalizations and poor growth and hematological status.
Preliminary data in children with SCD-SS show that vit A supplementation at the dose
recommended for healthy children failed to improve vit A status, resulting in no change in
hospitalizations, growth or dark adaptation. This indicates an increased vit A requirement
most likely due to chronic inflammation, low vit A intake and possible stool or urine loss.
The dose of vit A needed to optimize vit A status in subjects with SCD-SS is unknown.

Inclusion Criteria:

- Sickle cell disease, SS genotype (subjects with sickle cell disease only)

- Usual state of good health (no hospitalizations, emergency room visits, or unscheduled
acute illness clinic visits for two weeks prior to screening)

- Commitment to a 119-day study (subjects with sickle cell disease only), or a 4-day
study (healthy volunteers only)

Exclusion Criteria:

- Hydroxyurea initiated within the previous 6 weeks (subjects with sickle cell disease
only)

- History of stroke (subjects with sickle cell disease only)

- Other chronic conditions that may affect growth, dietary intake or nutritional status

- Retinoic acid (topical or oral), weight loss medication and/or lipid lowering
medications

- Subjects with a BMI greater than 98th percentile for age and sex

- Pregnant or lactating females (subjects who become pregnant during the course of the
study will not continue participation)

- Liver function tests >4 x upper limit of reference range

- Participation in another study with impact on vitamin A status (subjects with sickle
cell disease only)

- Use of multi-vitamin or commercial nutritional supplements containing vitamin A (those
who are willing to discontinue these supplements, with the approval of the medical
care team, will be eligible for the study after a 1 month washout period. Subjects
taking nutritional products without vitamin A will be eligible)

- Inability to swallow pills (subjects with sickle cell disease only)