Fatigue, physical activity, and musculoskeletal burden in adults surveyed during the COVID-19 pandemic: a cross-sectional indirect-association analysis.
Kılıç B & Özgün Başıbüyük G • International archives of occupational and environmental health • 2026
Fatigue showed a consistent concurrent association with musculoskeletal burden in older adults surveyed during the COVID-19 pandemic, whereas the association with total physical activity was less stable, and indirect associations through fatigue were identified for prior COVID-19 infection, female sex, and educational attainment.
Key Findings
Results
Higher Global Fatigue Index (GFI) was significantly associated with greater musculoskeletal discomfort burden as measured by the Cornell Musculoskeletal Discomfort Questionnaire (CMDQ).
B = 3.114, SE = 0.566, p < 0.001
This association remained positive across all sensitivity analyses including outcome transformation, winsorization, and influential-observation analysis
Regression models used heteroskedasticity-consistent (HC3) standard errors for robustness
The regression sample comprised 388 participants out of 400 surveyed
Results
Total physical activity (PASE score) was not significantly associated with musculoskeletal burden in the primary regression model.
B = -0.053, p = 0.245 in the primary model
The coefficient became significant only after exclusion of influential observations (B = -0.044, p = 0.027)
The authors characterized the physical activity association as 'less stable' compared to the fatigue association
Physical activity was measured using the Physical Activity Scale for the Elderly (PASE)
Results
Prior COVID-19 infection showed a significant indirect association with musculoskeletal burden estimated through fatigue (GFI).
Bootstrap 95% CI for the indirect estimate excluded zero: 15.55 (95% CI: 6.02–26.89)
Indirect associations were estimated using 5,000 bootstrap samples
The authors note these estimates are cross-sectional and do not establish temporal or causal mediation
Results
Female sex showed a significant positive indirect association with musculoskeletal burden estimated through fatigue.
Bootstrap 95% CI for the indirect estimate excluded zero: 8.66 (95% CI: 1.49–17.55)
Estimated using 5,000 bootstrap samples
The direction indicates that being female was associated with greater musculoskeletal burden indirectly via higher fatigue
Results
Higher educational attainment showed a significant negative indirect association with musculoskeletal burden estimated through fatigue.
Bootstrap 95% CI for the indirect estimate excluded zero: -4.61 (95% CI: -9.68 to -0.65)
The negative direction indicates higher education was associated with lower musculoskeletal burden indirectly via lower fatigue
Education was treated as an ordinal variable in the model
Estimated using 5,000 bootstrap samples
Results
More than half of the study sample reported zero musculoskeletal discomfort on the CMDQ.
54.1% of participants had a CMDQ score of zero
The sample consisted of 388 participants in the regression analysis (400 surveyed community-dwelling adults aged ≥ 60 years)
Participants were surveyed in Antalya, Türkiye, in 2021
The high proportion of zero scores reflects a skewed outcome distribution, which motivated the use of HC3 standard errors and sensitivity analyses
Methods
The study was conducted among community-dwelling older adults aged 60 years and above during the COVID-19 pandemic period.
400 participants were recruited from Antalya, Türkiye, in 2021
Participants were aged ≥ 60 years
Assessments used validated instruments: PASE for physical activity, CMDQ for musculoskeletal discomfort, and Multidimensional Assessment of Fatigue for fatigue (yielding the Global Fatigue Index)
The cross-sectional design prevents causal inference
What This Means
This research suggests that among older adults (age 60 and above) surveyed in Turkey during the COVID-19 pandemic, feeling more fatigued was consistently linked to experiencing greater musculoskeletal discomfort — that is, more pain or discomfort in muscles, joints, and body regions. This relationship held up across multiple statistical checks. In contrast, the amount of physical activity a person did was not clearly linked to musculoskeletal discomfort in the main analysis; that relationship only appeared after statistically removing participants whose data had an outsized influence on results, suggesting the physical activity finding is less reliable.
The study also found that certain characteristics — having previously had COVID-19, being female, and having lower education — were associated with greater musculoskeletal burden, and these associations appeared to work at least partly through fatigue. In other words, people who had prior COVID-19 infection or were female tended to report more fatigue, and more fatigue in turn was linked to more musculoskeletal discomfort. Those with higher education showed the reverse pattern, with lower fatigue potentially explaining some of their lower musculoskeletal burden.
Because this was a cross-sectional study — meaning all data were collected at a single point in time — it is not possible to determine whether fatigue causes musculoskeletal problems, whether musculoskeletal problems cause fatigue, or whether some other factor explains both. Still, this research suggests that fatigue may be an important factor to consider alongside physical activity when thinking about musculoskeletal health in older populations, and that groups such as COVID-19 survivors and women may warrant particular attention in this context.
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Kılıç B, Özgün Başıbüyük G. (2026). Fatigue, physical activity, and musculoskeletal burden in adults surveyed during the COVID-19 pandemic: a cross-sectional indirect-association analysis.. International archives of occupational and environmental health. https://doi.org/10.1007/s00420-026-02246-y