Subjective sleep quality and sleep problems in the general Japanese adult population

To dimensionally describe subjective sleep quality using the Pittsburgh Sleep Quality Index (PSQI) and estimate the prevalence rate of sleep problems (PSQI global score > 5) in the general Japanese adult population, 1871 subjects randomly selected from the 1995 Census were examined. The PSQI component scores (mean +/- SD) widely ranged (e.g. 0.04 +/- 0.31 in hypnotic medication use for males aged 20-29 years, 0.03 +/- 0.18 in hypnotic medication use for females aged 20-29 years, 1.10 +/- 0.94 in sleep latency for males aged 80 or older, 1.52 +/- 1.03 in sleep latency for females aged 80 or older). Statistical significance was found in each component score among age groups by gender. The PSQI global scores (mean +/- SD) by age groups ranged from 4.00 +/- 2.59 to 5.02 +/- 3.89 for males (P < 0.39) and 4.30 +/- 2.34 to 6.75 +/- 4.10 for females (P < 0.001). The respective prevalence rates of sleep problems were 26.4% (95% CI = 23.6, 29.3) for males and 31.1% (95% CI = 28.1, 33.9) for females.