The relationship between excessive daytime sleepiness, disability, and mortality, and implications for life expectancy.

OBJECTIVE

To assess the relationship between excessive daytime sleepiness (EDS), disability, mortality, and life expectancy (with and without disability) in a cohort of middle-aged American adults.

METHODS

The Wisconsin Longitudinal Study, a life-course study on 10,317 high school graduates from Wisconsin, was used to assess the odds ratio (OR) between EDS in 2004 for prevalent and incident disability to 2011 through multiple logistic regression, and to estimate the hazard ratio (HR) of EDS in 2004 for mortality over ten years through a Cox proportional hazard model. We estimated age and sex-specific rates for mortality and disability from US nation-wide survey data in 2004. Combining these data with age-, sex- and EDS-specific mortality rates and disability prevalence estimated from our study, we constructed Sullivan life tables for those with and without EDS. Life expectancy (total, with, and without disability) from age 60 was estimated for those with and without EDS.

RESULTS

The study participants were on average 64 years old and 47% were men. Those with EDS were more likely to develop disability than those without (OR 1.40, 95%CI 1.01-1.95). The HR for mortality associated with having EDS was 1.43 (95%CI 1.11-1.85). The results from life table analysis suggest that a sixty-year-old individual with EDS had a four-year decrease in disability-free life years, and no change in years lived with disability.

CONCLUSIONS

EDS is associated with higher likelihood of disability, increased risk of mortality, and substantially shorter disability-free life expectancy at age 60.