The association between sleep duration and self-rated health in the Korean general population.

STUDY
OBJECTIVES: Sleep duration is recognized as one of the most common issues in modern society. Self-rated health is a commonly used subjective health measure based on a single question asking individuals to rate their general health on a four- or five-point scale. However, few studies have examined the relationship between sleep duration and self-rated health. Here, we examined the association between sleep duration and poor self-rated health, using a large representative sample of the general Korean adult population.
DESIGN: We conducted a cross-sectional study of 15,252 participants in the Korea National Health and Nutrition Examination Survey IV (2007-2009) who were aged 19 years and older. Sleep duration was categorized as ≤ 5, 6, 7, 8, or ≥ 9 hours. The main outcome of interest was poor self-rated health (n = 3,705, 19.7%). Multiple logistic regression analysis was performed to examine the association between sleep duration and self-rated health.
RESULTS: We found both short (≤ 5 h) and long (≥ 9 h) sleep duration to be associated with poor self-rated health independent of sociodemographic, health risk, and health status variables. Compared with 7-h sleep duration, the multivariate odds of poor self-rated health were 1.358 times higher (95% CI 1.167-1.580) with short sleep duration and 1.322 times higher (95% CI 1.091-1.601) with long sleep duration. This association persisted in subgroup analyses of gender, body mass index, and age by gender.
CONCLUSIONS: In a large representative sample of the Korean general adult population, compared with sleep duration of 7 hours, we found a positive association between short and long sleep duration and poor self-rated health in Korean adults. Furthermore, the association between sleep duration and poor self-rated health was consistently present in subgroups divided by gender, age, and BMI.