Cosleeping in context - Sleep practices and problems in young children in Japan and the United States

Objective: To determine the relationship between cosleeping and sleep probl ems in cultures with very different sleep practices. Design: Interview study. Setting: Families in urban Japan and the United States identified through p ediatric and other professional contacts. Participants: Parents of healthy 6- to 48-month-old children (56 Japanese p arents and 61 white US parents). All children had been breast-fed and lived in 2-parent, middle-class households. Intervention: None Main Outcome Measure: Sleep practices and sleep problems. Results: More Japanese than US children coslept 3 or more times per week (5 9% vs 15%, P < .001). All cosleeping Japanese children regularly slept all night with their parents (vs :11% of US cosleepers, P < .001). Japanese and US children did not differ in part-night cosleeping (7% vs 13%, P = .37). Most Japanese children had adult company and body contact as they fell asle ep, and fathers slept separately in 23% of families. A greater proportion o f US children had regular bedtime struggles and night waking. Within the US sample, cosleeping was associated with more bedtime struggles (P < .001), night waking (P < .01), and overall stressful sleep problems (P < .01). In the Japanese sample, cosleeping was associated only with night waking (P < .05); however, the proportion of cosleeping Japanese children with frequent night waking was at the level reported for US children who slept alone (30 % vs 23%, P = .47). Conclusions: Cultural differences seem to influence the relationship betwee n sleep practices and sleep problems. The experience of the Japanese famili es indicates: that cosleeping per se :is not associated with increased slee p problems in early childhood.