Validation of Actigraph accelerometer estimates of total energy expenditure in young children.

Purpose: To assess the validity of two equations based on the Actigraph CSA/MTI accelerometer for prediction of total energy expenditure (TEE).

Research Methods And Procedures: The criterion was TEE measured using the doubly labeled water method in 85 children, mean age 4.6 years (SD 1.1), over 7 days in the pre-schoolers and 10 days in the school-age participants. Children wore the Actigraph concurrently during waking hours, for 3 of 7 days (pre-schoolers) or 7 of 10 days (school-age children). We tested two prediction equations based on accelerometry. Agreement between predicted and measured TEE was assessed using the 'Bland Altman' approach.

Results: Mean TEE measured by doubly-labeled water was 5.8 MJ/d (SD 1.6). Mean error for the Ekelund equation was + 0.3 MJ/d (limits of agreement -3.7 to + 4.3), and for that of Puyau et al. was -0.3 MJ/d (limits of agreement + 3.2 to -3.8).

Conclusions: Simple approaches using the Actigraph appear to be inadequate for the estimation of free-living TEE in young children at present.