  Background. Few studies on the relations between sleep quantity and/or
quality and cognition were conducted among pre-schoolers from healthy general
population. We aimed at identifying, among 3 years old children, early factors
associated with intelligence quotient estimated through Weschler Preschool and
Primary Scale Intelligence-III test and its indicators: full-scale-, verbal-
and performance-intelligence quotients and their sub-scale scores. Methods. We
included 194 children from the French birth-cohort AuBE with both available
Weschler Preschool and Primary Scale Intelligence-III scores at 3y and sleep
data. Information was collected through self-questionnaires at birth, 6, 12, 18
and 24 months. A day/night sleep ratio was calculated. Results. Mean scores
were in normal ranges for verbal-, performance- and full-scale-intelligence
quotients. In multivariate models, being a $\ge$3 born-child and watching
television $\ge$1 hour/day at 24 months were negatively associated with all
intelligence quotient scores while collective care arrangement was positively
associated. Night waking at 6 and frequent snoring at 18 months were negatively
associated with performance intelligence quotient, some subscales and
full-scale-intelligence quotient contrary to day/night sleep ratio at 12
months. No association was observed between early sleep characteristics and
verbal intelligence quotient. Conclusion. We showed that early features
including infant sleep characteristics influence intelligence quotient scores
at 3 years old. Some of these may be accessible to prevention.
