Validation of the WAge Index: an integrated tool for age-inclusive assessment of physical and psychosocial working environments

Test-retest reliability, measurement invariance, and usability of a condensed physical and psychosocial workplace assessment instrument (WAge Index) among manufacturing and service workers aged 18–65 across three European countries: a prospective observational validation study

Status

Recruiting

Phases

Unknown

Study type

Observational

Source

ISRCTN

Registry ID

ISRCTN15422730

Enrollment

200

Registered

2026-04-21

Start date

2026-05-04

Completion date

Unknown

Last updated

2026-07-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Musculoskeletal disorders, psychosocial wellbeing, physical capacity, and workplace health across age groups Other

Interventions

Prospective observational study with two measurement time points (T1 and T2), conducted in manufacturing and service workplaces in Portugal, Spain, and Poland. The interval between measurements will b

Eligibility

Sex/Gender

All

Age

18 Years to 65 Years

Inclusion criteria

Inclusion criteria: 1. Currently employed in manufacturing or service sector organisations participating in the WAge project in Portugal, Spain, or Poland 2. Correct understanding of the native language 3. Currently performing their work as their main occupation for at least 20 hours per week

Exclusion criteria

Exclusion criteria: 1. Pregnancy 2. Acute illnesses, accidents, or other health conditions that currently affect physical capacity 3. Sickness absence on the day of the measurements

Design outcomes

Primary

Measure	Time frame
Invariance of the WAge Index factor structure measured using confirmatory factor analysis (CFA) at T1 and T2, with progressive invariance testing (configural, metric, scalar). Model fit evaluated using CFI (Comparative Fit Index), TLI (Tucker-Lewis Index), RMSEA (Root Mean Square Error of Approximation), and SRMR (Standardized Root Mean Square Residual). Invariance assessed by change in CFI (?CFI = 0.01) and RMSEA between nested models. Measured at T1 (baseline) and T2 (3-6 weeks after T1);Test-retest reliability measured using intraclass correlation coefficients (ICC) using a two-way mixed-effects model (ICC(A,k)). Standard error of measurement (SEM) computed for each scale. Measured at T1 and T2;Usability and acceptability measured using completion time (minutes) and item non-response rates (percentage) analysed descriptively. Qualitative feedback from structured sessions analysed using thematic analysis at T2	—

Measure

Time frame

Invariance of the WAge Index factor structure measured using confirmatory factor analysis (CFA) at T1 and T2, with progressive invariance testing (configural, metric, scalar). Model fit evaluated using CFI (Comparative Fit Index), TLI (Tucker-Lewis Index), RMSEA (Root Mean Square Error of Approximation), and SRMR (Standardized Root Mean Square Residual). Invariance assessed by change in CFI (?CFI = 0.01) and RMSEA between nested models. Measured at T1 (baseline) and T2 (3-6 weeks after T1);Test-retest reliability measured using intraclass correlation coefficients (ICC) using a two-way mixed-effects model (ICC(A,k)). Standard error of measurement (SEM) computed for each scale. Measured at T1 and T2;Usability and acceptability measured using completion time (minutes) and item non-response rates (percentage) analysed descriptively. Qualitative feedback from structured sessions analysed using thematic analysis at T2

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Countries

Norway, Poland, Portugal, Spain

Contacts

Public ContactVictor Gonzalez Sanchez

victor.gonzalez@sintef.no+47 (0)46423790

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Jul 23, 2026