After being informed about the study, all patients who gave written informed consent were questioned and diagnosed as lifelong PE according to the definition of International Society of sexual medicine (ISSM) by an experienced urologist. Since erctile dysfunction (ED) may accompany PE, the presence of ED symptoms was evaluated by the International Index of Erectile Function (IIEF-5), and those with IIEF-5 score <22 were excluded from the study. Age- and sex-matched control cases without lifelong PE were selected randomly among cases attending the hospital for a checkup procedure. A total of 114 patients with PE and 103 control subjects with similar sociodemographic characteristics were included in the study. A detailed medical and sexual history was taken, which included self-estimated intravaginal ejaculatory latency time (IELT), by an experienced sexual therapist. Moreover, Arabic Index of Premature Ejaculation (AIPE), Pittsburgh Sleep Quality Index (PSQI) and Morningness-Eveningness Questionnaire (MEQ) were administered to all participants.
Chronotype (or circadian preference) has previously been shown to be associated with sexual attitudes and behaviors and is an important factor affecting sexual satisfaction. The fact that some neurobiological variables, which are thought to have a role in ejaculation physiology, are also effective in the processes of sleep and the regulation of circadian rhythm, and evidence supporting the relationship between circadian preferences and sexual desire and sexual behavior; suggests that ejaculation disorders may be related to circadian preference. The aim of the present study was to investigate the relationship between intravaginal ejaculatory latency time (IELT), severity of disease and chronotype in lifelong PE.