Identifying non-genetic factors associated with trigger finger.

Background: The non-genetic factors predisposing to trigger finger (TF) have mostly been characterised in small studies from individual institutions. Here, we aimed to provide a more complete picture of TF and its associations.

Methodology: This case-control study used cross-sectional data from the UK Biobank population-based cohort to identify and determine the strength of associations of phenotypic variables with TF. We performed multivariable logistic regression of a multitude of phenotypic factors associated with TF.

Results: We identified 2250 individuals with medical and surgical diagnostic codes for TF, and 398,495 controls. TF was found to be significantly associated with age (OR 1.04, 95% CI 1.03-1.04, P < 2.23×10), female sex (OR 1.22, 95% CI 1.08-1.39, P = 2.35×10), body mass index (OR 1.10, 95% CI 1.04-1.16, P = 5.52×10), carpal tunnel syndrome (OR 9.59, 95% CI 8.68-10.59, P < 2.23×10), Dupuytren's disease (OR 4.89, 95% CI 4.06-5.89, P < 2.23×10), diabetes mellitus without complications (OR 1.35, 95% CI 1.15-1.58, P = 2.03×10) and with complications (OR 2.46, 95% CI 1.90-3.17, P = 4.98×10), HbA1c (OR 1.01, 95% CI 1.01-1.02, P = 8.99×10), hypothyroidism (OR 1.24, 95% CI 1.07-1.43, P = 4.75×10) and rheumatoid arthritis (OR 1.33, 95% CI 1.06-1.68, P = 0.014).

Conclusion: Our results provide evidence supporting the well-known risk factors such as diabetes mellitus, carpal tunnel syndrome, age and female sex. Furthermore, we can confirm putative associations such as hypothyroidism, obesity and rheumatoid arthritis, while providing evidence against others such as hypertension and hyperlipidaemia. A novel finding arising from this study is the strong association with Dupuytren's disease. Our study design allowed us to identify these associations as being independent from carpal tunnel syndrome, thereby indicating a shared pathophysiology between this disease and TF.