“…All studies examined adults, except one study examining both children and adults (age range 10–82 years) ( 11 ) and, in most studies, the psoriatic population was age- and sex-matched with the control population ( 12 – 23 ). Nine studies included patients with plaque psoriasis only ( 11 – 13 , 18 , 20 , 23 – 26 ), 6 studies included patients with mixed psoriasis types ( 15 , 17 , 21 , 22 , 27 , 28 ) and 7 studies did not specify the type of psoriasis ( 14 , 16 , 19 , 29 – 32 ). Fifteen studies examined patients with mild, moderate or severe psoriasis ( 11 – 13 , 15 – 22 , 24 , 25 , 27 , 29 ), 2 studies examined patients with mild psoriasis ( 14 , 32 ) and 4 studies reported no information on psoriasis severity ( 23 , 28 , 30 , 31 ).…”