Obesity as a risk factor for rheumatic diseases – epidemiological insights

Obesity is increasingly recognised as a major modifiable risk factor for the development and progression of several rheumatic diseases, including rheumatoid arthritis (RA), psoriatic arthritis (PsA), osteoarthritis (OA), systemic lupus erythematosus (SLE), and gout. Epidemiological studies and meta-analyses consistently demonstrate that obesity not only increases the risk of developing these conditions but also worsens disease activity, impairs treatment response, and amplifies comorbidities such as cardiovascular disease and diabetes. The relationship is particularly strong for OA and gout, but substantial evidence also links obesity to increased risk and severity of RA, PsA, and SLE (1). Obesity promotes a chronic low-grade inflammatory state through adipokines and cytokines, which may drive both the onset and progression of these diseases. In addition to this inflammatory pathway, obesity also generates joint damage through mechanical overload. Obesity is linked to increased disease activity, poorer physical function, higher pain, and greater comorbidity burden.

Epidemiologic studies suggest high rates of obesity in RA and PsA, with up to 40% of RA and SLE patients, and 45% of PsA patients classified as obese (2,3). PsA consistently shows higher obesity rates than RA, and both are higher than in the general population. Additional data from a large cohort study report obesity prevalence of 40.1% in OA (40.1%) and 19.7% in gout patients (4).

Rheumatoid Arthritis  – Obesity is associated with a modestly increased risk of developing RA, with meta-analyses showing a 25–31% higher risk in obese individuals compared to subjects of normal weight (5). In women, central adiposity (waist circumference, waist-to-hip ratio) may be even more predictive than BMI, and the risk appears to be stronger for early-onset RA.

Psoriatic Arthritis – Obesity increases the risk of developing PsA among individuals with psoriasis, with risk rising in a weight-dependent manner. In the CORRONA registry, 59% of obese PsA patients met criteria for metabolic syndrome, with obesity being more prevalent in PsA than RA patients (6).

Osteoarthritis – Obesity is a robust and independent risk factor for OA, especially for knee OA, with obese individuals having up to 4.5 times the risk compared to those of normal weight (7). The risk is not limited to weight-bearing joints, suggesting metabolic and inflammatory mechanisms beyond mechanical load.

Systemic Lupus Erythematosus – Obesity is linked to increased SLE risk, particularly in younger women, with up to 88% higher risk in some cohorts (8). Obesity and elevated leptin levels are associated with higher SLE activity and also increase adverse pregnancy outcomes in SLE (9).

Gout – Obesity is a strong, modifiable risk factor for gout. There are studies supporting a causal relationship between obesity, elevated serum urate, and gout (10). Thus, the rising obesity rates contribute to the global increase in gout prevalence.

In conclusion, obesity is a well-established, modifiable risk factor for rheumatic diseases, including RA, PsA, OA, lupus and gout. Obesity promotes chronic low-grade inflammation via adipokines and pro-inflammatory cytokines, contributing to immune dysregulation and joint damage. Weight management is increasingly recognised as a key preventive and therapeutic strategy in rheumatic disease care.

References

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