In a recent study published in PLOS Global Public Health, researchers examined whether pain mediates or moderates the link between physical activity and depressive symptoms.

Study: Physical activity and depression symptoms in people with osteoarthritis-related pain: A cross-sectional study. Image Credit: Jacek Chabraszewski/Shutterstock.com

Background

Osteoarthritis is a leading source of chronic pain and has increased depression incidence worldwide. This discomfort impairs movement and physical, social, and mental health.

According to research, there is a moderately favorable relationship between pain severity and depression symptomology among individuals with osteoarthritis. Persistent pain is more likely to lead to depression, with more intense and long-lasting pain raising the likelihood of severe depression and suicidal thoughts.

Physical activity is a primary mental health factor in adults with osteoarthritis, and physical activity therapies can help reduce depressive symptoms. However, it is uncertain whether physical exercise is related to fewer depressive symptoms, independent of pain intensity.

It is critical to investigate the differential relationship between physical activity levels and depressive symptoms in patients with low, medium, and high pain levels to create tailored therapies.

About the study

In the present study, researchers investigated the significance of pain in the association between physical activity and depression in osteoarthritis patients.

The researchers recruited osteoarthritis individuals with orthopedic appointments at Melbourne’s public hospitals. Recruitment began on September 22, 2021, and concluded on August 29, 2022.

Adults on the waitlist between January 2018 and June 2022 had osteoarthritis mentioned on their medical referrals or experienced physical exercise-associated joint discomfort with morning stiffness in the joints lasting less than or equal to 30 minutes.

Individuals with hereditary illnesses such as dementia, those requiring specialist visits in the following six weeks, and those slated for surgery were all excluded from the study.

They gathered cross-sectional data on pain intensity, physical exercise, and depressive symptoms via surveys given via email or completed over the phone. They also retrieved information from the subjects’ medical records, such as age, biological sex, and damaged joints.

The researchers used the Patient Health Questionnaire (PHQ-9) and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) to assess depression-like symptoms. They also used the Active Australia Survey (AAS) to examine physical activity levels and calculated pain intensity ratings using the four-item scale (P4).

The researchers used descriptive statistics and linear regressions to analyze participant characteristics.

They performed mediation and moderation analyses to determine the effect of pain levels on the association between physical exercise and depression, controlling for joint-specific and demographic factors. They estimated Spearman correlations for physical activity and Pearson correlation coefficients for the others.

Results

The research comprised 552 participants, among whom 55% were female, with a mean age of 63 years. The most affected joints were the knee (44%), hip (16%), shoulder (14%), and foot (13%), with 9.0% having multiple joint involvement.

Overall, 34% of participants reported moderate or severe depression, with 19% reporting major depressive disorders and 11% reporting other depressive syndromes.

Participants reported an average of 5.2 hours of physical exercise each week. Overall, 48% of individuals were physically active, 37% were inactive, and 15% were sedentary. On a 0 to 40 scale, the mean pain level was 27.7.

Individuals undertaking more physical exercise experienced fewer depressive symptoms and discomfort. Pain was independently positively related to depression, with individuals reporting higher degrees of pain and experiencing increased depressive symptoms.

The inverse association between physical exercise and depression varied according to pain intensity, with the correlation being higher in those with more pain.

Mediation analyses indicated that physical exercise is indirectly and negatively associated with depressive symptoms via reducing pain levels. The team found the highest degrees of pain related to the highest probable benefit in reducing depressive symptoms through physical exercise.

Conclusions

The findings indicate that physical exercise is critical for treating depressive symptoms in individuals with osteoarthritis-associated pain. The most robust link between physical activity levels and depression was observed in individuals with the most pain, showing that physical activity may benefit mental health.

According to the study, the level of depressive symptoms can alter the mediating effect of pain, with increased severity lowering the direct and indirect effects of pain on physical activity.

A comprehensive approach to healthcare, encompassing mental health assistance, educational resources, and physical activity support, may be required.

Future studies should explore the influence of comorbidities, body mass index, medication, and disease duration on the link between physical activity, pain, and mood.

Longitudinal data analysis and randomized controlled trials should investigate the relationship’s long-term stability and influence on pain levels.