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Sleep and sleep disordered breathing in the first year of life: a Canadian birth cohort study Open Access


Other title
sleep duration
birth cohort
sleep disordered breathing
sleep apnea
Type of item
Degree grantor
University of Alberta
Author or creator
Lau, Amanda A.
Supervisor and department
Senthilselvan, A (Public Health)
Mandhane, P (Medicine & Dentistry)
Examining committee member and department
Carson, V (Physical Education and Recreation)
Department of Public Health Sciences
Date accepted
Graduation date
Master of Science
Degree level
Inadequate childhood sleep may adversely affect neurodevelopment, behaviour, and metabolic function. Few population-based studies have examined sleep duration and sleep disordered breathing (SDB) within the first year of life. Families in the Edmonton site of the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort study completed sleep questionnaires (Pediatric Sleep Questionnaires (PSQ) and Brief Infant Sleep Questionnaire (BISQ)), and questionnaires related to child health, environmental/household exposures, and parental health, stress, and sleep when their child was 3, 6, 9, and 12 months of age. The association between self-soothing and sleep duration (i.e. total amount of sleep during day and night as reported on the BISQ) was analyzed longitudinally with multivariate linear regression using generalized estimating equations (GEE) methods with exchangeable correlation matrix and robust errors. Infant sleep was also analyzed cross-sectionally when the child was 3, 6, 9, 12 months of age using multivariable linear regression. The association between BMI Z-Scores and SDB (i.e. answering positively to more than 1/3 of the PSQ questions or a PSQ score of 0.33 or greater) was analyzed with cox proportional hazard modeling. The earliest PSQ score of 0.33 or greater was used to define time to SDB. Follow-up started at birth and data was censored at 12 months of age if the infant did not have SDB or at the child’s age if and when loss to follow up occurred. In an additional analysis, PSQ questions relating to rhinitis were excluded and added in the multivariate model to investigate the association between rhinitis and SDB. Of the 845 Edmonton CHILD participants, 765 had sleep duration data. Sleep duration was inversely associated with age. On average, infants slept 14.08 hours at 3 months, 13.66 hours at 6 months, 13.41 hours at 9 months, and 13.51 hours at 12 months of age. Non self-soothing was consistently associated with shorter sleep duration in longitudinal and cross-sectional analyses. A multivariate longitudinal analysis stratified by birth order was performed. Self-soothing infants (-0.31 hours; 95% Confidence Interval (95%CI) -0.51, -0.11; p<0.001 for first-born; -0.57 hours; 95%CI -0.76, -0.37; p<0.001 for subsequent-born), sleep times after 21:00 (-0.67 hours; 95%CI -0.86, -0.45; p<0.001 for first-born; -0.61 hours; 95%CI -0.81, -0.42; p<0.001 for subsequent-born), and a parent who perceived their child’s sleep as a small problem (-0.62 hours; 95%CI -0.84, -0.40; p<0.001 for first-born; -0.86 hours; 95%CI -1.08, -0.65; p<0.001 for subsequent-born) and very serious problem (-2.19 hours; 95%CI -3.00, -1.38; p<0.001 for first-born; -1.91 hours; 95%CI -2.52, -1.31; p<0.001 for subsequent-born) were significantly associated with shorter sleep duration in first-born and subsequent-born infants. A child’s age was significantly associated with shorter sleep duration in subsequent-born infants but not first-born infants. In subsequent-born infants, infants that were fed only solid foods slept 0.87 hours less (95%CI -1.33, -0.41) and infants that were mixed-fed slept 0.74 hours less (95%CI -1.03, -0.50) than breastfeed infants (p<0.001 for both.) Feeding type was not significantly associated with sleep duration in first-born infants. Of the 845 Edmonton CHILD participants, 763 had SDB data. By 12 months of age, 13% (101/763) of infants had SDB. BMI Z-scores were not significantly associated with SDB risk (Hazard Ratio(HR) 1.06 per standard deviation, 95%CI 0.80, 1.41; p=0.68). In multiple variable Cox regression adjusted for gender, factors that increased SDB risk included late prematurity (HR 2.09; 95%CI 1.05, 4.15; p=0.05), maternal symptoms for SDB (HR 1.80; 95%CI 1.12, 2.90; p=0.02), and otitis media (OM) (HR 2.09 per OM event, 95%CI 1.36, 3.31; p=0.00). Sleep duration decreased SDB risk (HR 0.82 per hour; 95%CI 0.70, 0.96; p=0.02). In the multivariate model excluding PSQ questions regarding rhinitis, symptoms for rhinitis became the strongest risk factor for SDB (HR 3.08, 95%CI 2.05, 4.67; p<0.001). Problematic infant sleep may be modifiable. First-born and subsequent-born infants have fundamentally different parent-infant interactions. Regardless of birth order, parent-infant interactions may be the most direct link in affecting infant sleep-wake regulation. Behavioural interventions that focus on parent-child interactions may be utilized to achieve optimal sleep in childhood. To mitigate SDB risk, treating or monitoring rhinitis in early childhood may reduce adverse consequences. Screening susceptible infants (late prematurity, males, infant with mother with SDB symptoms, infants with OM and rhinitis) may be a valid long-term strategy for SDB prevention and treatment.
This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for the purpose of private, scholarly or scientific research. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
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