In a retrospective study, blood sugar levels were compared for a group of psoriatics and a control group. Twenty-nine percent of the psoriatics had abnormal blood sugar levels. This apparently high incidence was found to be similar to the expected incidence in controls of the same age. Psoriatics were also found to be similar to the controls in regard to obesity and a family history for diabetes mellitus.
Lynch PJ. Psoriasis and Blood Sugar Levels. Arch Dermatol. 1967;95(3):255-258. doi:10.1001/archderm.1967.01600330013003