Early diagnosis is critical to reduce long-term disability in patients with JIA by ensuring prompt treatment. The aim of this cross-sectional study was to evaluate the salivary gland function in JIA, addressing specifically oligoarticular (JIA1) and polyarticular (JIA2) subtypes, compared with healthy controls. This may contribute to the identification of salivary risk indicators of the disease that may help diagnosis at an early stage or even before the onset of other clinical evidence.
Twenty-eight patients with JIA1, 28 patients with JIA2, according to the ILAR criteria, and 28 healthy controls (C) were included in the study. Exclusion criteria were any concurrent medical condition. Data on medication, dietary and oral hygiene habits were collected using a questionnaire. All patients underwent oral examination and saliva measurement.
While stimulated salivary flow rate (SFR) was significantly lower in JIA1 compared with JIA2 and C (P < 0.001), both salivary buffer capacity and pH were similar in the two JIA groups but statistically different from C (P = 0.002 and P = 0.010, respectively). Children with very low SFR (<3.5 ml) exhibited a 16-fold higher likelihood of being affected by JIA1 rather than JIA2 (P = 0.003), while no association was observed between low flow rate and JIA subtype (P = 0.744).
These preliminary data suggest impairment of salivary gland function as a risk indicator for JIA1 with no association with dietary habits and drug intake.