<h3>Background</h3> Age at onset of disease (AOD) refers to the time period at which a patient experiences the first symptom(s). AOD varies among autoimmune diseases (ADs) and has been related to prognosis in some of them. Genetic, environmental and immunological factors may influence the AOD. Sjögren's syndrome (SS) is considered an AD affecting mostly older women. However, information about how does AOD influence the course of SS is scarce. <h3>Objectives</h3> To evaluate the factors associated with AOD in SS. <h3>Methods</h3> This was a two-phase study. First, a cross sectional analytical study was undertaken in 294 consecutive adult patients with SS (by <i>AECG</i> criteria) with a mean duration of disease of 6.4 years. Clinical, laboratory and sociodemographic variables were investigated through a structured medical record review. AOD was categorized in early (17-35 years) and late (>35 years) according to the 25th percentile of AOD in our cohort. Odds Ratios (ORs) with their 95% confidence intervals were calculated, and p-values <0.003 were considered as significant, after Bonferroni correction. Second, a systematic literature review in adult SS, following the PRISMA guidelines, was performed in PubMed and EMBASE databases to address the state of the art about this topic. <h3>Results</h3> Significant differences were not observed between early-AOD (73/294) and late-AOD (221/294) groups, except for the presence of cutaneous vasculitis (OR= 0.15, 95% CI: 0.07-0.39, p<0.0005). Out of a total of 2,512 articles retrieved, 11 were selected for final analyses. Some of them showed differences in serological abnormalities and disease manifestations with a lack of statistical significance in most of them. Just one article found AOD as a prognostic factor (i.e., Lymphoma). <h3>Conclusions</h3> In contrast with other ADs, AOD has not a critical effect on disease expression and autoimmune response in patients with SS. Late-onset traits are more sensitive to environmental variation rather than genetic influence. Therefore, these results, together with the fact that SS has a similar clinical and immunological presentation worldwide, may serve to design better strategies aimed to discover the etiological factors of disease. <h3>References</h3> Amador-Patarroyo MJ, et al. <i>Autoimmune Dis</i>. 2012;1-7. Botsios C, et al. <i>Joint Bone Spine</i>. 2011;78:171-4. Haga HJ, et al. <i>Scand J Rheumatol</i>. 1999;28:227-32. Ramos-Casals M, et al. <i>Lupus</i>. 1998;7;202-6. <h3>Disclosure of Interest</h3> None Declared
