Within and Between-rater Reproducibility and Validity of a Novel Portable Laser Height Meter
Conditions: Body Height, Lasers, Reproducibility of Results, Anthropometry
Sponsor: Aalborg University Hospital

August 25, 2019 
Title: 
Within and between-rater reproducibility and validity of a novel portable laser height meter 
 
Registration: 
Clinicaltrials.gov identifier: 
 
Protocol version: 1 
 
Funding:  
This study will be funded by the Department of Geriatric and Internal Medicine, Aalborg University 
Hospital, Aalborg, Denmark, and Department of Clinical Medicine, Aalborg University, Aalborg, 
Denmark. 
 
Authors: 
Sørensen GV1,2, Ryg J3,4, Masud T5, Riis J1,2, Danielsen MB1,2, Andersen SA1,2, Jørgensen MG1 
1. Department of Geriatric Medicine, Aalborg University Hospital, Aalborg, Denmark  
2. Department of Clinical Medicine, Aalborg University, Aalborg, Denmark 
3. Department of Geriatric Medicine, Odense University Hospital, Odense, Denmark  
4. Department of Clinical Research, University of Southern Denmark, Odense, Denmark 
5. Department of Healthcare for Older People, Nottingham University Hospitals NHS Trust, Nottingham, 
England 
 
Author contributions: 
GS, MGJ and SA designed the study. GS developed the portable laser distance metre. GS is the guarantor 
of the study and wrote the draft for the protocol with help from all authors. GS, JRI and MBD will 
perform data collection. GS will perform statistical analyses and write the draft for the manuscript of the 
paper. JR, TM, JRI, MBD, and SA will assist in interpretation of results, read, provide feedback and 
approve the final manuscript of the paper. 
 
Sponsor contact information 

August 25, 2019 
The study was sponsored by Department of Geriatric Medicine, Aalborg University Hospital, Denmark. 
Contact name: 
Stig Andersen, MD, PhD, Professor,  
E-mail: lasa@rn.dk 
 
Address: 
Geriatrisk afdeling, Gl. Rød bygn. 6, 2. Etage, Aalborg Universitetshospital, Syd, Hobrovej 18-22, 9000 
Aalborg: 
 
Background: 
Height may be used to calculate body mass index [1] and reference interval for normal lung function [2], 
together with serving as an indicator for possible vertebral fractures in osteoporosis [3] and growth 
retardation in children [4]. Height is typically measured using the “gold standard” a fixed stadiometer in 
a clinical setting [2,5]. However, newer studies have investigated alternative ways of measuring height 
using portable measuring devices with laser distance metres [6,7]. The advantage with this type of 
measure is the ability to potentially perform reliable measure in settings outside clinical controlled 
settings. Recently researchers [6] developed a measuring device which required adjustments of 
measuring axes by hand, which resulted in a measurement error of 0.35 cm compared with 0.20-0.30 cm 
in fixed stadiometers [5]. In order to optimise this, the author's suggested that future measuring devices 
using laser distance meters should be fixed in one or more measurement axes. Thus, we have developed 
a portable height device (PHD), which is fixated in two axes using a laser distance metre. 
 
Objectives: 
Primary objective: 
To investigate inter– and intra-rater reproducibility of the PHD  
 
Secondary objectives: 
To assess agreement between the PHD and wall-fixed digital stadiometer. 
 
Methods: 
Participants: 

August 25, 2019 
We expect to enrol approximately 30 adults, 18+ years old men and women in the study. Participants 
will be recruited through convenience sampling in order to maximise recruitment efforts during the time 
of the study. We will collect data on gender, age, and height.  
Ethics: 
Written informed consent will be obtained from all participants prior to the study. The local ethics 
committee will be consulted for approval of the study. Approval will also be obtained from the Danish 
Data Protection Agency.  
 
Measuring devices: 
Portable laser measuring device: 
A laser distance meter (Bosch Zamo, Robert Bosch 
GmbH, Gerlingen-Schillerhöhe, Germany) will be 
mounted perpendicularly to the end of a wooden lath 
(3x4x50 cm) (see Figure 1). The other end of the lath 
will be mounted perpendicular to a T-shaped metal 
plate which will fixate the x- and z-axis of the laser 
measuring device. The PHD will measure vertically 
down in its z-axis from the participant’s vertex to the 
floor in front of the participant. 
 
Stadiometer (reference standard): 
We will use a fixed stadiometer as a reference (Harpenden Stadiometer, Holtain Limited, Crosswell, 
UK). 
 
Procedure: 
Measurements will be performed at Aalborg University Hospital, Aalborg, Denmark. Two raters will 
independently perform height measurements in two separate rooms with each measuring device (PHD 
and fixed stadiometer) on all participants. Each rater will perform three measures per device. During 
measurements, participants will be asked to stand flat on the floor (hard surface) without shoes. 
Furthermore, participants will be asked to stand with their heels positioned together and against the wall 
Figure 1 

August 25, 2019 
during both type of measurements. Each rater will make sure that participants’ heads are be positioned 
in the Frankfurt plane, and encourage participants to stand with a straight back against the wall. 
Stadiometer (reference standard):  
The measuring device will be pulled down to the skull. Afterwards, the participant will be asked to take 
a deep breath and hold it, after which the measurement will be performed. 
Portable laser measuring device: 
The lath with the laser distance meter will be placed on top of 
the participant’s vertex and fixated in two axes by holding the 
T-shaped piece against the wall (See Figure 2). The lath will be 
rotated until the laser distance meter points vertically, which is 
done using a bubble level mounted on the end of the lath. The 
laser distance meter will be activated by clicking on the 
“START” button. Participants are asked to take a deep breath 
and hold it, after which the measurement will be locked and 
recorded. Following each measurement, the participant will 
take a step away from the measuring area and afterwards step 
back again to replicate the measurement procedure. 
 
Blinding: 
The blinding process is illustrated in Figure 3. All 30 participants will be measured using the laser 
distance meter first by each rater. When this stage is complete, measurements will be secured and 
inaccessible, in order to blind the raters when performing stadiometer measurements afterwards. We will 
assume that each rater will not be able to remember each participants’ height when 30 participants are 
measured consecutively. After the stadiometer measurements have been performed, data will also be 
secured and inaccessible. Afterwards, this entire procedure will be repeated once more. Measurements 
will be collected using a data capturing tool (REDCap) [8]. 
 
Figure 2 

August 25, 2019 
 
Figure 3 

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Statistics: 
Participants: 
Age will be reported in mean with standard deviations, and gender will be reported in proportions. Both 
height measures will have 95% confidence intervals reported. 
Agreement: 
Mean of all three measurements per rater per measuring device per participants will be calculated. The 
difference between the means will be calculated by subtracting the mean laser measurement from the 
mean stadiometer measurement. This will also be performed with only the mean of the two first 
measurements, and finally also the first measurement. Thus, we would be able to evaluate whether one 
measurement would have similar agreement with two or three measurements. We will generate Bland 
Altman plots with limits of agreement (LOA) together with standard error of measurements (SEM) and 
coefficient of variation (c.v) for all the above-mentioned combinations. 
Reliability: 
We will calculate Intraclass Correlation Coefficients (ICC) with 95% confidence intervals between 
measuring devices.  
Software: 
Statistics will be performed using Microsoft Excel for Mac version 16.28 (Microsoft Office, Microsoft 
Corporation, WA) and IBM SPSS Statistics for MacOS version 25.0 (IBM Corporation, Armonk, NY). 
 
Conflicts of interest: 
The authors report no conflicts of interest. 
 
Dissemination: 
We plan to publish in an English-language journal. The reporting of the study will follow the current 
guidelines for reliability and agreement studies (GRRAS) [9]. 
 
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August 25, 2019 
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