Psoriatic arthritis (PsA) is a progressive and destructive inflammatory arthritis that affects approximately one-third of patients with psoriasis following an average of 7 years of psoriasis onset. The presence of PsA not only causes articular symptoms (pain, swelling, and joint stiffness), but substantially increases the risk of comorbidities, impairs quality of life, and leads to considerable medical expenditures. Currently, the role of lifestyle and environmental factors in the development of PsA remains limited and contradictory, leading to unclear knowledge on this topic. Therefore, for a paper published in the Journal of the American Academy of Dermatology, my colleagues and I performed a systematic review and meta-analysis of observational studies to assess the lifestyle and environmental factors associated with PsA development among patients with psoriasis.

We conducted a comprehensive search of the PubMed, EMBASE and the Cochrane Library electronic databases from database inception to May 2, 2020. Cohort or case‐control studies reporting at least one lifestyle or environmental risk factor for PsA in patients with psoriasis were eligible. A total of 16 articles out of 4,528 citations were included in our final meta-analysis.

Modifiable Lifestyle Risk Factors for PsA

Of the eligible studies, eight, comprising 240,546 participants with psoriasis, assessed the risk of PsA onset with regard to BMI. Obesity (BMI ≥ 30 kg/m2) and overweight (25-30 kg/m2) were significantly associated with increased risk for PsA development (Figure) in patients with psoriasis (pooled odds ratio [OR], 1.75; 95% confidence interval [CI], 1.42-2.16 & pooled OR, 1.50; 95% CI, 1.08-2.09, respectively). In addition, summary of two further studies showed a 6% increased PsA risk for each unit increment in BMI (pooled OR, 1.06; 95% CI, 1.03-1.10).

Regarding other lifestyle factors, the summary ORs were 0.99 (95% CI, 0.88-1.13) for alcohol drinkers, 0.89 (95% CI, 0.75-1.06) for ever smokers in nine studies, 0.89 (95% CI, 0.74-1.08) for current smokers in six studies (Figure), and 0.98 (95% CI, 0.83-1.16) for past smokers in five studies.

Trauma as a Risk Factor for PsA

From the aspect of physical and psychological trauma (Table), the presence of PsA was significantly associated with a history of any cause of trauma (pooled OR, 1.33; 95% CI, 1.16-1.54) or fracture (pooled OR, 1.46; 95% CI, 1.22-1.74). There was a trend toward increased risk of progression to PsA regarding depression/anxiety, death in family, changing job, and moving between homes, but these associations were not statistically significant. For the rest of combinable factors—including college education, female hormonal exposure, ever pregnancy, treatment for fertility—no significant associations with PsA risk were detected.

Promote Awareness & PsA Risk Reduction

According to the best available datasets, obesity was associated with an increased incidence of PsA in patients with psoriasis, indicating that weight control may be an important strategy worth considering in susceptible individuals with psoriasis. Individuals with psoriasis and a history of physical trauma have significantly increased risk of PsA, suggesting that biomechanical trauma may be a trigger in the pathogenesis of PsA (“synovioentheseal complex” concept).

Our results strengthen public health efforts to promote awareness and reduce the risk of PsA development in patients with psoriasis, and furthermore deepen our understanding of the etiology of PsA. In daily practice, physicians who care for patients with psoriasis should be aware of the associations of obesity and physical trauma with increased risk of PsA and educate at-risk patients to alter their lifestyle behaviors and try to avoid physical trauma.