Sleep Hygiene Index: reliability and validity of the Persian version in the male population

Introduction: Inadequate sleep hygiene may result in difficulties in daily functioning; therefore, reliable scales are important to measure sleep hygiene. The purpose of this study was to assess the psychometric properties of the Persian version of Sleep Hygiene Index (SHI) in the male population.

Methods: In this study, 787 men, who were selected by cluster random sampling, filled out the SHI, Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and Insomnia Severity Index (ISI). A subset of the participants (20%) completed SHI after a 4–6 week interval to measure test–retest reliability. Then, the Pearson product–moment correlation coefficients of SHI against PSQI, ESS, and ISI were computed to demonstrate the construct validity of SHI. The factor structure of SHI was evaluated by explanatory factor analysis.

Results: The interclass correlation coefficient was 0.85, and SHI was found to have a good test–retest reliability (r = 0.86, p < 0.01). The SHI was positively correlated with the total score of PSQI (r = 0.62, P < 0.01), ESS (r = 0.63, P < 0.01) and ISI (r = 0.61, P < 0.01). Exploratory factor analysis extracted three factors, namely “sleep–wake cycle behaviors” (four items), “bedroom factors” (three items), and “behaviors affecting sleep” (six items).