Associations of Socioeconomic Adversity and Sleep With Allostatic Load Among Toddlers

An accelerometer will be placed on the wrist or ankle of the child while the child sleeps in their home. Caregivers will be instructed to keep the accelerometer on their toddler's ankle to measure sleep duration, latency and sleep efficiency. Seven nights of data will be obtained because actigraphy is most reliably measured in young children over this time frame.

Salivary and hair cortisol measurements were used to obtain a change in baseline from 12 to 24 months. Data on the timing of the saliva collection will be collected using a Medical Electronic Monitoring System (MEMScapTM) - a digital memory cap that records the timing and frequency of opening. Cortisol will be measure in the morning and bedtime samples. A small amount of hair (30mg) will be cut from the posterior vertex of the child's head. Due to the expected variability in hair length of toddlers, documentation of hair length will be completed. Each centimeter represents 1 month history of stress and ideally 3 cm of hair length will be collected to provide a three month history of stress.