Changes in sleep duration in Spanish children aged 2-14 years from 1987 to 2011

Objective: Historical decreases in sleep duration in children have been documented worldwide; however, there is sparse information on sleep duration in differing cultural regions. We assess sleep duration and its trends for children in Spain from 1987 to 2011 and associated sociodemographic characteristics.

Methods: Data from eight Spanish National Health Surveys, from 1987 to 2011, were collected on parent-reported sleep duration and associated socio-demographic characteristics including age, sex, parental level of education, child body mass index (BMI), and physical activity. A total of 24,867 children aged 2-14 years were included in the final sample.

Results: Overall, short sleep duration increased to 44.7% from 29.8% in 1987. Decreasing sleep duration trends were found in all demographic groups, decreasing by around 20 minutes in 24 hours from 1987 to 2011; decreasing to 10 hours 16 minutes in 2- to 5-year olds, 9 hours 31 minutes in 6- to 9-year-olds, and 8 hours 52 minutes in 10- to 14-year-olds. No difference in sleep duration was found between girls and boys. Sleep duration was associated with year of survey, age, level of parental education, obesity, and exercise.

Conclusions: Almost 45% of children in Spain are not sleeping the recommended amount. Regional differences in sleep attitudes and duration alongside a lack of consistency in cut-offs for age-appropriate ideal sleep in literature is a barrier for international comparison and highlights the need for research in physiological sleep requirements. With the association of short sleep duration with many different health outcomes, sleep should be considered as a modifiable lifestyle factor and a public health issue.