Sleep duration and health in young adults

Background: Both long and short sleep durations have been associated with negative health outcomes in middle-aged and older adults. This study assessed the relationship between sleep duration and self-rated health in young adults. Methods: Using anonymous questionnaires, data were collected from 17 465 university students aged 17 to 30 years who were taking non - health- related courses at 27 universities in 24 countries. The response rate was greater than 90%. Sleep duration was measured by self-report; the health outcome was self-rated health; and age, sex, socioeconomic background, smoking, alcohol consumption, body mass index, physical activity, depression ( Beck Depression Inventory), recent use of health services, and country of origin were included as covariates. Results: Sixty-three percent of respondents slept for 7 to 8 hours; 21% were short sleepers ( 6%, < 6 hours; 15%, 6-7 hours); and 16% were long sleepers (10%, 8-10 hours; 6%, > 10 hours). Compared with the reference category (7-8 hours), the adjusted odds ratio of poor health was 1.56 (95% confidence interval [CI], 1.22-1.99) for respondents sleeping 6 to 7 hours and 1.99(95% CI, 1.31-3.03) for those sleeping less than 6 hours. The same significant pattern was seen when the results were analyzed separately by sex. When respondents from Japan, Korea, and Thailand ( characterized by relatively short sleep durations) were excluded, the adjusted odds ratios were 1.33 ( 95% CI 1.03-1.73) and 1.62 ( 95% CI, 1.06-2.48) for those sleeping 6 to 7 hours and less than 6 hours, respectively. There were no significant associations between self-rated health and long sleep duration. Conclusion: Our data suggest that short sleep may be more of a concern than long sleep in young adults.