Mother-child bed-sharing trajectories and psychiatric disorders at the age of 6 years

Background: Little is known about the effect of bed-sharing with the mother over the child mental health. Methods: Population-based birth cohort conducted in Pelotas, Brazil. Children were enrolled at birth (n=4231) and followed-up at 3 months and at 1, 2, 4, and 6 years of age. Bed-sharing was defined as "habitual sharing of the bed between the child and the mother, for sleeping, for part of the night or the whole night". Trajectories of bed sharing between 3 months and 6 years of age were calculated. Mental health was assessed at the age of 6 years using the Development and Well-Being Assessment instrument that generates psychiatric diagnosis according to ICD-10 and DSM-W criteria. Odds ratios (OR) with 95% confidence intervals were obtained by multivariate logistic regression. Results: 3583 children were analyzed. Four trajectories were identified: non bed-sharers (44.4%), early-only (36.2%), late-onset (12.0%), and persistent bed-sharers (7.4%). In the adjusted analyses persistent bed-sharers were at increased odds of presenting any psychiatric disorder (OR=1.7; 1.2-2.5) and internalizing problems (OR=2.1; 1.4-3.1), as compared to non bed-sharers. Among the early-only bed-sharers OR for any psychiatric disorder was 1.4 (1.1-1.8) and for internalizing problems 1.6 (1.2-2.1). Limitations: Although the effect of bed-sharing was adjusted for several covariates including the family socioeconomic status, maternal mental health and excessive crying, there was no information on maternal personal reasons for bed-sharing. Mothers that bed-share intentionally and those that bed-share in reaction to a child sleep problem may have a different interpretation of their children behavior that may bias the study results. Conclusion: Bed-sharing is a common practice in our setting and is associated with impaired child mental health at the age of six years.