Evelyne Touchette

Dyssomnias and Parasomnias in Early Childhood

OBJECTIVES. Our aim for this study was to determine the prevalence of dyssomnias and various parasomnias in early childhood and to describe their temporal evolution, gender differences, and correlates. METHODS. This research is part of a longitudinal study of child development. A randomized, 3-level, stratified survey design was used to study a representative sample of infants who were born in 1997–1998 in the province of Quebec (Canada). When the children were 2.5 years of age, 1997 families agreed to be interviewed. The presence of dyssomnias or parasomnias was obtained from a self-administered questionnaire that was completed by the mother at each round of measures. RESULTS. The percentage of children with frequent night wakings decreased steadily from 36.3% at age 2.5 to 13.2% at age 6. Similarly, the percentage of children who had difficulty falling asleep at night decreased significantly from 16.0% at ages 3.5 and 4 to 10% at age 5 and to 7.4% at age 6. The overall prevalence of each parasomnia for the period studied was as follows: somnambulism, 14.5%; sleep terrors, 39.8%; somniloquy, 84.4%; enuresis, 25.0%; bruxism, 45.6%; and rhythmic movements, 9.2%. Persistent somnambulism at age 6 was significantly correlated with sleep terrors and somniloquy. Persistent sleep terrors at age 6 were also correlated with somniloquy. Finally, persistent sleep terrors at age 6 were correlated with frequent night wakings. Separation anxiety was associated with persistent night wakings and with somnambulism, bruxism, sleep terrors, and somniloquy. CONCLUSIONS. There is a high prevalence of night wakings and sleep-onset difficulties in preschool children. Parasomnias are highly prevalent in early childhood and are associated with separation anxiety. However, they have little impact on sleep duration.

Developmental trajectories of body mass index in early childhood and their risk factors: an 8-year longitudinal study.

OBJECTIVES To identify groups of children with distinct developmental trajectories of body mass index (BMI), calculated as weight in kilograms divided by height in meters squared, between the ages of 5 months and 8 years and identify early-life risk factors that distinguish children in an atypically elevated BMI trajectory group. DESIGN Prospective cohort study. SETTING Families with a child born between October 1997 and July 1998 in the province of Quebec, Canada. PARTICIPANTS A representative sample of children (N = 2120) selected through birth registries for the Quebec Longitudinal Study of Child Development. Children for whom BMI data were available for at least 5 time points were retained in the present study (n = 1957). MAIN EXPOSURES Early-life factors putatively associated with BMI, assessed by maternal report. OUTCOME MEASURE Group-based trajectories of childrens BMI, identified with a semiparametric modeling method from raw BMI values at each age. RESULTS Three trajectories of BMI were identified: low-stable (54.5% of children), moderate (41.0%), and high-rising (4.5%). The high-rising group was characterized by an increasing average BMI, which exceeded international cutoff values for obesity by age 8 years. Two maternal risk factors were associated with the high-rising group as compared with the low-stable and moderate groups combined: maternal BMI (odds ratio, 2.38; 95% confidence interval, 1.38-4.54 for maternal overweight and 6.33; 3.82-11.85 for maternal obesity) and maternal smoking during pregnancy (2.28; 1.49-4.04). CONCLUSIONS Children continuing on an elevated BMI trajectory leading to obesity in middle childhood can be distinguished from children on a normative BMI trajectory as early as age 3.5 years. Important and preventable risk factors for childhood obesity are in place before birth.

Short Sleep Duration and Body Mass Index: A Prospective Longitudinal Study in Preadolescence

Short sleep duration is associated with incidence of overweight and obesity in preadolescent children. The authors performed regression analyses on data from the Quebec Longitudinal Study of Kindergarten Children (1986-1987), a prospective cohort study comprising 1,916 preadolescent children in Canada. The aim was to assess associations between time spent in bed and body mass index reported by mothers after adjusting for numerous confounding factors, such as pubertal status. Time-in-bed and body mass index trajectories were computed using a semiparametric model mixture. Time-in-bed trajectories were classified as short (15% of the preadolescents), 10.5-hour (68%), and 11-hour (17%) sleep-duration trajectories, decreasing over time. Body mass index trajectories were classified as normal weight (68% of the preadolescents), overweight (27%), and obese (5%). The short sleep trajectory was associated with an increased odds ratio of being in the overweight body mass index trajectory (odds ratio (OR)=1.55, 95% confidence interval (CI): 1.39, 1.71) or in the obese body mass index trajectory (OR=3.26, 95% CI: 3.20, 3.29) compared with the 11-hour trajectory. One hour less of sleep per night at 10 years of age was associated with an increased odds ratio of being overweight (OR=1.51, 95% CI: 1.28, 1.76) or obese (OR=2.07; 95% CI: 1.51, 2.84) at 13 years of age.

Subclinical eating disorders and their comorbidity with mood and anxiety disorders in adolescent girls.

The present study assesses the prevalence of subclinical eating disorders and examines their comorbidity with mood and anxiety disorders in a sample of adolescent girls. A DSM-III-R computerized self-reported interview was administered to 833 adolescent girls (mean age=15.7±0.5 years) from a population sample to assess the prevalence of subclinical eating disorders, major depression, dysthymia, separation anxiety, and generalized anxiety disorders. The prevalence of subclinical anorexia nervosa (restricting subtype) was 3.5%, 13.3% for weight concerns (restricting subtype), 3.8% for subclinical bulimia nervosa, and 10.8% for subclinical binge eating disorder. Girls with subclinical anorexia nervosa had a higher prevalence of separation anxiety diagnosis, and they reported significantly more major depressive and generalized anxiety symptoms compared with girls reporting no eating disorders. Girls with weight concerns reported significantly more major depressive, separation, and generalized anxiety symptoms compared with girls reporting no eating disorders. Girls with subclinical bulimia nervosa or binge eating disorder had a higher prevalence of mood disorders (major depression and dysthymia) compared with girls reporting no eating disorders. Furthermore, girls with subclinical bulimia nervosa or binge eating disorder also reported significantly more anxiety symptoms (separation anxiety and generalized anxiety) compared with girls reporting no eating disorders. In summary, adolescent girls suffering from subclinical eating disorders should be investigated concomitantly for mood and anxiety disorders while those suffering from mood and anxiety disorders should be investigated simultaneously for subclinical eating disorders.

Risk factors and consequences of early childhood dyssomnias: New perspectives.

Dyssomnias are largely under-diagnosed in infants and toddlers. This literature review proposes an integrative model based on empirical data on determinants and consequences of sleep disturbances occurring in early life. This model proposes that parental behaviors that impede the childs autonomy toward sleep periods are primary grounds for the development of dyssomnias, e.g., parental presence until the child falls asleep, and putting an already sleeping child to bed. The model also indicates the serious potential consequences of a modest but chronic loss of sleep in childhood. At least three developmental domains could be directly affected: behavioral/social competence, cognitive performance, and physical condition. Thus, children with short nocturnal sleep duration before age 3.5 years show increased risk of high hyperactivity-impulsivity scores and low cognitive performance at 6 years compared to children who sleep 11 h per night, after controlling for potentially confounding variables. Moreover, persistent short sleep duration in early infancy increased the risk of suffering of obesity at 6 years of age, after controlling for potentially confounding variables. Finally, the importance of allowing the child to sleep at least 10 h per night in early childhood is stressed, as the National Sleep Foundation Poll suggests, for optimal child development.

Short Nighttime Sleep-Duration and Hyperactivity Trajectories in Early Childhood

OBJECTIVES: Our objectives were to investigate the developmental trajectories of nighttime sleep duration and hyperactivity over the preschool years and to identify the risk factors associated with short nighttime sleep duration and high hyperactivity scores. DESIGN, SETTING, AND PARTICIPANTS: Nighttime sleep duration and hyperactivity were measured yearly by questionnaires administered to mothers of 2057 children from age 1.5 to 5 years. Developmental trajectories of nighttime sleep duration and hyperactivity throughout early childhood were analyzed to determine interassociations. A multinomial logistic regression was performed to determine which factors among selected child, maternal, and family characteristics and parental practices surrounding sleep periods in early childhood were associated with short nighttime sleep duration and high hyperactivity scores. RESULTS: The trajectories of nighttime sleep duration and hyperactivity were significantly associated. The odds ratio (OR) of reporting short nighttime sleep duration was 5.1 for highly hyperactive children (confidence interval [CI]: 3.2–7.9), whereas the OR of reporting high hyperactivity scores was 4.2 for persistently short sleepers (CI: 2.7–6.6). The risk factors for reporting short nighttime sleep duration and high hyperactivity scores were (1) being a boy, (2) having insufficient household income, (3) having a mother with a low education, and (4) being comforted outside the bed after a nocturnal awakening at 1.5 years of age. CONCLUSIONS: The risk of short nighttime sleep duration in highly hyperactive children is greater than the risk of high hyperactivity scores in short sleepers. Preventive interventions that target boys living in adverse familial conditions could be used to address these concomitant behavioral problems.

Associations Between Sleep-Wake Consolidation and Language Development in Early Childhood: A Longitudinal Twin Study

STUDY OBJECTIVES The objectives were (1) to assess associations between sleep consolidation at 6, 18 and 30 months and language skills at 18, 30, and 60 months; and (2) to investigate the genetic/environmental etiology of these associations. DESIGN Longitudinal study of a population-based twin cohort. PARTICIPANTS 1029 twins from the Quebec Newborn Twin Study. MEASUREMENTS AND RESULTS Sleep consolidation was derived from parental reports of day/night consecutive sleeping durations. Language skills were assessed with the MacArthur Communicative Development Inventory at 18 and 30 months and the Peabody Picture Vocabulary Test at 60 months. The day/night sleep ratio decreased significantly from 6 to 30 months. The 6- and 18-month ratios were negatively correlated with subsequent language skills. Children with language delays at 60 months had less mature sleep consolidation at both 6 and 18 months than children without delays and those with transient early delays. Genetic and regression analyses revealed that the sleep ratio at 6 months was highly heritable (64%) and predicted 18-month (B = -0.06) and 30-month language (B = -0.11) mainly through additive genetic influences (R(Gs) = 0.32 and 0.33, respectively). By contrast, the sleep ratio at 18 months was mainly due to shared environment influences (58%) and predicted 60-month language (B = -0.08) through shared environment influences (R(Cs) = 0.24). CONCLUSIONS Poor sleep consolidation during the first 2 years of life may be a risk factor for language learning, whereas good sleep consolidation may foster language learning through successive genetic and environmental influences.

Phase advance of sleep and temperature circadian rhythms in the middle years of life in humans

Age-related changes in sleep may be linked to modifications in the circadian timing system. This study compared sleep patterns and unmasked circadian temperature parameters between a group of young subjects and a group of middle-aged subjects. Habitual bedtime and waketime were earlier in the middle-aged than in the young. In addition, middle-aged subjects reported a greater orientation toward morningness and they showed an earlier phase of temperature rhythm. No differences were found in amplitude of temperature rhythm or in habitual phase angle between sleep and the temperature rhythm. In conclusion, a phase advance of sleep and temperature circadian rhythm is already apparent in people in their forties and fifties. These changes precede modifications in amplitude or in habitual phase angle.

Short sleep duration and increased risk of hypertension: a primary care medicine investigation.

Objectives: Compelling evidence from laboratory-based and population-based studies link sleep loss to negative cardiovascular health outcomes. However, little is known about the association between sleep duration and hypertension in primary care health settings, independently of other well controlled clinical and biochemical characteristics. We investigated the association between sleep duration and the prevalence of hypertension adjusting for 21 potential confounding factors in a noncontrolled primary care sample. Methods: The sample included 1046 French adults older than 40 years (mean age, 55.5 years), who visited any of the general practitioners of primary care centers in the Paris area. Blood pressure (BP) readings, blood samples and standardized health and sleep questionnaires were performed on each participant. Hypertension inclusion criteria were either high BP measurements (SBP ≥140 mmHg or DBP ≥90 mmHg) or the use of antihypertensive medications. Sleep duration was recorded as the self-reported average number of hours of sleep per night during the week. Logistic regressions were performed to test the association between hypertension and sleep duration adjusted for sociodemographic, clinical, biochemical, lifestyle, psychological and sleep disorder covariates. Results: Compared to the group sleeping 7 h, individuals sleeping 5 h or less had an increased odds ratio (OR) for the prevalence of hypertension [OR = 1.80, 95% confidence interval (1.06–3.05)], after adjusting for 21 potential confounders which did not markedly attenuate this association. Conclusion: Our data provide further epidemiologic evidence that with no specific selection in primary care medicine, usual short-sleep duration increases the risk of hypertension prevalence in adults over 40 years.

Sex differences in the association between sleep duration, diet and body mass index: a birth cohort study

Sex differences in the effects of sleep duration on dietary intake and eating behaviours were examined prospectively in relation to overweight/obesity at ages 6 and 7. Using data from a representative sample (QLSCD 1998–2010) of children born in the province of Québec (Canada), 1106 children were followed to age 6 and 1015 to 7 years. Average nocturnal sleep duration was surveyed annually from 2.5–6 years, food‐frequency and eating behaviour questionnaires were administered at age 6, and body weight and height were measured at 6 and 7 years. Associations were examined longitudinally and mediation examined with adjustments for potential confounders. In boys and girls, shorter sleep duration patterns were associated significantly with less favourable dietary intakes at 6 years: boys consumed vegetables and fruits less frequently and meats/alternatives more frequently than boys with longer sleep patterns; and girls consumed vegetables, fruits and milk products less frequently and soft‐drinks more frequently than girls with longer sleep patterns. However, boys with shorter sleep patterns were also more likely to eat at irregular hours or to eat too much/fast at 6 years. These behaviours, and not dietary intake, mediated an inverse association between sleep duration and overweight/obesity in boys. Sleep duration did not associate with any problem eating behaviours or overweight/obesity in girls. Shorter sleep in early childhood appears to associate with problematic eating behaviours in boys and diet quality in both sexes, regardless of an association with overweight/obesity. This is important for public health and should be considered in relation to other diet‐related diseases.