Work Strain Hits Harder in Those With ACPA-Positive RA

TOPLINE:

Among patients newly diagnosed with rheumatoid arthritis (RA), higher work-related physical strain was linked to more severe joint inflammation at diagnosis in those positive for anti-citrullinated protein antibodies (ACPAs), but not in those negative for these antibodies, and this link weakened after treatment began.

METHODOLOGY:

In this observational cohort study, researchers assessed whether work-related physical strain was associated with how severe joint inflammation was at RA diagnosis and whether this differed by ACPA status.
They included 417 patients with recent-onset RA at a Dutch tertiary centre between August 2010 and March 2020. Of these, 197 had ACPA-positive RA (mean age, 55 years; 63% women) and 220 had ACPA-negative RA (mean age, 59 years; 64% women).
Work-related physical strain was estimated from job titles with a standard system and expressed as the percentage of heavy lifting. Joint inflammation was measured using a swollen joint count of 44 joints and MRI of the hands and forefeet to score total inflammation, including synovitis, tenosynovitis, osteitis, and intermetatarsal bursitis.
Patients were followed up at 4, 8, and 12 months after baseline and then yearly for up to 5 years.

TAKEAWAY:

In patients with ACPA-positive RA, each 10% increase in work-related physical strain was associated with 7% more swollen joints at diagnosis (incidence rate ratio [IRR], 1.07; 95% CI, 1.02-1.12), mainly affecting hand joints (IRR, 1.07; 95% CI, 1.01-1.13).
In patients with ACPA-positive RA, each 10% increase in work-related physical strain was associated with 5% higher MRI-detected joint inflammation at diagnosis (IRR, 1.05; 95% CI, 1.01-1.09), driven by more bone marrow inflammation (osteitis; IRR, 1.07; 95% CI, 1.01-1.13).
The effect of work-related physical strain on swollen joint counts was not observed after starting disease-modifying antirheumatic drugs over 5 years of follow-up.
In patients with ACPA-negative RA, work-related physical strain was not associated with swollen joints or MRI-detected joint inflammation.

IN PRACTICE:

“While our findings suggest that mechanical strain may play a role in exacerbating joint inflammation in ACPA-positive RA, these do not imply that patients should stop working or change profession,” the authors wrote.

“Occupational therapy is a potentially helpful treatment option for individual RA patients who experience difficulties with daily activities, including work,” they added.

SOURCE:

This study was led by Dennis A. Ton, MD, Leiden University Medical Center, Leiden, Netherlands. It was published online on January 08, 2026, in Rheumatology.

LIMITATIONS:

The assessment of physical strain was based on job categories and did not capture differences at an individual level. Some patients may have moved from high- to low-strain jobs because of symptoms, causing potential misclassification. The findings mainly applied to younger working patients; effects in retired or unemployed patients were not assessed.

DISCLOSURES:

This study received funding from the Dutch Arthritis Foundation and the European Research Council under the European Union’s Horizon 2020 research and innovation programme. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.