Impact of Exercise on Body Composition in Premature Infants

Premature birth is recognized as the single most important health problem in maternal child
health in the US. Paradoxically, both failure to thrive and obesity are now known to be
associated with prematurity, as are osteopenia (a condition where bone mineral density is
lower than normal) and increased risk of fracture, and increased risk of cardiovascular
disease later in life. We lack cohesive approaches to mitigate these profound threats to
health. Despite promising new research demonstrating that physical activity can stimulate
the growth of muscle and bone even during intrauterine life (perhaps through metabolic
programming), there have been very few attempts to implement and study physical activity
interventions in the premature baby.

The challenges are substantial and include:

- measuring body composition

- assessing physical activity

- engaging caregivers as partners in the intervention

- identifying plausible and testable biological mechanisms

- designing interventions that actually increase physical activity and match the rapid
pace of motor development early in life

A developmentally dynamic physical activity intervention has been designed and pilot
tested-one that engages the caregiver as a partner. Using techniques and tools as
far-ranging as Dual X-ray Absorbiometry (DXA), smart phones, doubly labeled water, and
lightweight, wireless accelerometers developed specifically for this purpose, the working
hypothesis is that the one-year intervention will augment lean body mass (primary outcome
variable) and improve bone mineralization and the ratio of lean to fat tissue (secondary
outcome variables). The study will gauge the impact of the physical activity intervention on
the balance between circulating anabolic mediators (insulin-like growth factor-I and growth
hormone binding protein) and inflammation-associated cytokines (interleukin-6, and
interleukin-1 receptor antagonist), which antagonize muscle and bone growth.

We will additionally:

1. begin to explore how physical activity influences circulating endothelial progenitor
cells, which are increasingly viewed as markers of vascular health very early in life

2. take advantage of this prospective, interventional study to explore potential genetic
determinants of growth in babies born prematurely.

3. Finally, any study involving the premature infant and the data associated with it must
be viewed in light of the critical relationship between the mother and baby.

The potential broad impact of early life interventions has been recently demonstrated by the
success of the "Back-To-Sleep" campaign in mitigating sudden infant death syndrome. Should
the positive effects of augmented exercise on body composition be supported, we would then
anticipate widespread benefit in preventing long-term health consequences of prematurity at
relatively low cost.

Infant Inclusion criteria:

- Infant is a healthy, growing NICU inpatient.

- Caregiver ≥18 years of age

- Infant gestational age at birth <29weeks

- Infant gestational age at time of study recruitment >34 wks, on full feeds and
nearing discharge

Infant Exclusion criteria:

- Significant lung disease of prematurity requiring supplemental oxygen or
corticosteroids at discharge

- Significant intraventricular hemorrhage, grade III -IV

- Necrotizing entrocolitis

- Tracheostomy

- Bone Diseases

- Osteogenesis Imperfecta

- Hip or knee joint anomalies

- Arthrogryposis

- Fractures

- Skin disorders (e.g., Erythematus Bullosis)

- Symptomatic congestive heart disease

- Any other conditions or congenital anomalies likely to severely impact the ability of
the premature baby and caregiver to participate in a demanding study