Short sleep in young adults: Insomnia or sleep debt? Prevalence and clinical description of short sleep in a representative sample of 1004 young adults from France.

Background: Increasing evidence suggests an association between short sleep with adverse health outcomes: obesity, type 2 diabetes and hypertension. But there are few or no data on "who these short sleepers are" in the general population.
Objectives: To describe short sleepers and the associated sleep disorders in young adults.
Methods: Cross-sectional telephone survey in a representative sample of 1004 French young adults (25-45 years old). Total sleep time (TST), insomnia, snoring, sleepiness and daytime consequences were assessed using subjective validated tools. Short sleepers were defined as sleeping <6h a weekday (sleep+nap+pauses). Sleep debt was defined as those who "sleep 90 min less than the sleep they need to be in good shape."
Results: Prevalence of short sleep was 18%, insomnia 12%, and sleep debt 20% in the total group. Among short sleepers, 16% had insomnia, 45% sleep debt, and 39% neither. Short sleepers were significantly mostly males, blue collar workers and more overweight and obese compared to nonshort sleepers. Working >10h per day, smoking and drinking coffee after 5p.m. were also significantly associated with short sleep. Short sleepers had higher Epworth sleepiness scale ESS scores (7.8 vs 6.7; p = 0.0058) and more sleepiness while driving (11.5% vs 2.9%; p < 0.0001).
Conclusion: Short sleep is highly prevalent in young adults but is not an homogeneous group, including both insomniacs and subjects with or without sleep debt. Short sleep has to be defined more precisely in order to better understand its impact on public health.
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