Assessment of sleep in the National Social Life, Health, and Aging Project

The relationship of sleep to health has been an active area of research in recent years, and the National Social Life, Health, and Aging Project (NSHAP) expanded sleep data collection in Wave 2 with enhanced core questions and a novel sleep module that included an objective measure of sleep duration and quality.

A randomly selected one-third of Wave 2 participants and their spouses or coresident partners were invited to participate in the sleep module. Objective sleep data were collected using wrist actigraphy, an accelerometer that records an integrated measure of motion over short epochs (15 s each). This information is stored and subsequently analyzed to determine sleep and wake periods by epoch. Individuals were instructed to wear the actiwatches for 72 hr. Several sleep parameters were derived from the accelerometer. Individuals concurrently kept a sleep diary.

Sleep actigraphy data were successfully collected from 780 individuals. Many of the survey-based and the actigraph-estimated sleep parameters varied by age and gender. However, age and gender patterns often differed for sleep characteristics that were both asked and measured, such as sleep duration.

The survey and actigraphy data provide different information about sleep characteristics. The opportunity to examine actigraph-estimated sleep characteristics in a nationally representative sample of older adults allows novel analyses of the associations of sleep parameters with social and health data.