Sedentary Behavior in Preschoolers: How Many Days of Accelerometer Monitoring Is Needed?

Wonwoo Byun,Michael Beets,Russell Pate

doi:10.3390/ijerph121013148

Abstract

The reliability of accelerometry for measuring sedentary behavior in preschoolers has not been determined, thus we determined how many days of accelerometry monitoring are necessary to reliably estimate daily time spent in sedentary behavior in preschoolers. In total, 191 and 150 preschoolers (three to five years) wore ActiGraph accelerometers (15-s epoch) during the in-school (≥4 days) and the total-day (≥6 days) period respectively. Accelerometry data were summarized as time spent in sedentary behavior (min/h) using three different cutpoints developed for preschool-age children (<37.5, <200, and <373 counts/15 s). The intraclass correlations (ICCs) and Spearman-Brown prophecy formula were used to estimate the reliability of accelerometer for measuring sedentary behavior. Across different cutpoints, the ICCs ranged from 0.81 to 0.92 for in-school sedentary behavior, and from 0.75 to 0.81 for total-day sedentary behavior, respectively. To achieve an ICC of ≥0.8, two to four days or six to nine days of monitoring were needed for in-school sedentary behavior and total-day sedentary behavior, respectively. These findings provide important guidance for future research on sedentary behavior in preschool children using accelerometry. Understanding the reliability of accelerometry will facilitate the conduct of research designed to inform policies and practices aimed at reducing sedentary behavior in preschool children.

Highlights

Childhood obesity is a significant public health concern because of its long-term detrimental health effects [1,2,3,4]
Estimating the specific reliability of in-school sedentary behavior is important because interventions designed to reduce sedentary behavior are often childcare center- or preschool-based [51,52,53,54,55], and researchers need a reliable measure to quantify their outcome of interest
Our results showed that in-school sedentary behavior was more stable than total-day sedentary behavior across days of the week, as evidenced by higher intraclass correlations (ICCs) and the lower number of days required to achieve 80% reliability for in-school sedentary behavior compared to total day sedentary behavior

Summary

Introduction

Childhood obesity is a significant public health concern because of its long-term detrimental health effects [1,2,3,4]. The rapid increase of obesity rates in American children and youth are known to be very difficult to reverse [5]. According to recent data from a representative sample, a third of American children and youth are classified as either overweight or obese [6]. Childhood obesity is associated with numerous adverse health outcomes including type 2 diabetes, insulin resistance, hypertension, dyslipidemia, fatty liver disease, obstructive sleep apnea, and psychosocial difficulties in adulthood [7,8]. Contemporary children spend a significant amount of their waking hours in sedentary behavior and this may result in negative health consequences.

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