Many naps, one nap, none: A systematic review and meta-analysis of napping patterns in children 0-12 years

Abstract

The onset of monophasic sleep, in which napping ceases and sleep consolidates into a single night period, is a key developmental milestone of childhood. Yet to date, there is little consensus regarding the timing of cessation of napping in children. The aim of the current study is to examine global evidence regarding napping patterns in childhood, and, through meta-analysis, describe patterns of napping cessation and duration observed in children aged 0-12 y. A systematic search of all published, original research articles reporting children's napping patterns, by age, was conducted. The quality of studies was assessed, and meta-analysis of eligible studies undertaken. Risk of bias and heterogeneity of measurement was high. Current evidence indicates that less than 2.5% of children cease napping prior to age 2, while 94% cease napping by age 5. The preschool period (3-5 y; 36-60 mo) represents a particularly dynamic period in napping cessation, with large variation in rates of napping across studies evidencing potential ecological effects. Future studies should focus on understanding of the underlying mechanisms explaining individual variations in napping patterns and the extent to which patterns of napping may represent a marker of child development.

Keywords: Cessation; Children; Daytime; Diurnal; Infants; Monophasic; Nap; Patterns; Sleep; Transition.

Fig. 1.

PRISMA flow diagram.

Fig. 2.

Risk of bias scores, including internal and external validity, across napping studies. Note. Red = high risk (≥7); Blue = moderate risk (4–6); Green = low risk (≤3). External validity scores range 0–4; internal validity scores range 0–6; total range 0–10. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 3.

Napping studies that met inclusion criteria across geographical region.

Fig. 4.

Random effects meta-analysis of napping cessation by age groupings. Individual studies are ordered by proportion napping and then median age of sample range within each age grouping. Age = median of age range (months), non = number children not napping, n = number children, I² = 0–100 indictor of heterogeneity between studies (only for random effect rows), p = p-value for I² and if less than 0.05 means significant heterogeneity (only for random effect rows), and W = weighting in random effects analysis.

Fig. 5.

Random effects meta-analysis of napping duration by age groupings. Individual studies are ordered by napping duration and then median age of sample range within each age grouping. Age = median of age range (months), n = number children, I² = 0–100 indictor of heterogeneity between studies (only for random effect rows), p = p-value for I² and if less than 0.05 means significant heterogeneity (only for random effect rows), and W = weighting in random effects analysis.