Prevalence of erectile dysfunction/ED according to various approaches and age categories (in percent). ED ‘EF all’: based on the erectile function (EF) domain (including all men). ED ‘EF confidence’: based on the EF domain (including only sexually active men plus inactive men with a low confidence of achieving and maintaining an erection). ED ‘EF active’: based on the EF domain including only sexually active men. ED ‘subjective’: based on participant's subjective judgment on the presence of ED. ED ‘DSM-IV’: as defined in the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV). Confidence intervals of the proportions.