“…The articles excluded from the analysis, and the reasons for their exclusion, are shown in Figure 1 . The included articles were 11 case–control (Fadel et al., 2013 ; Ganzetti et al., 2015 ; Lazaridou et al., 2013 ; Mendes, Cota, Costa, Oliveira, & Costa, 2019 ; Painsi, Hirtenfelder, Lange‐Asschenfeldt, Quehenberger, & Wolf, 2017 ; Preus et al., 2010 ; Sarac, Kapicioglu, Cayli, Altas, & Yologlu, 2017 ; Sharma, Raman, & Pradeep, 2015 ; Skudutyte‐Rysstad, Slevolden, Hansen, Sandvik, & Preus, 2014 ; Woeste, Graetz, Gerdes, & Mrowietz, 2019 ) and 2 cohort studies (Keller & Lin, 2012 ; Nakib, Han, Li, Joshipura, & Qureshi, 2013 ) published in the English language between 2010 and 2019 and conducted in 13 different countries and regions across Asia, Europe, and America. Of these 13 articles, 9 showed prevalence of periodontitis or psoriasis (Antal, Braunitzer, Mattheos, Gyulai, & Nagy, 2014 ; Ganzetti et al., 2015 ; Keller & Lin, 2012 ; Lazaridou et al., 2013 ; Mendes et al, 2019 ; Nakib et al., 2013 ; Painsi et al., 2017 ; Preus et al., 2010 ; Skudutyte‐Rysstad et al., 2014 ), five reported data for continuous variables, including PD (Mendes et al., 2019 ; Sharma et al., 2015 ), clinical attachment level (CAL) (Mendes et al., 2019 ; Sharma et al., 2015 ), number of missing teeth (Skudutyte‐Rysstad et al., 2014 ; Woeste et al., 2019 ), or number of remaining teeth (Fadel et al., 2013 ; Mendes et al., 2019 ).…”