Kati Heinonen

Short Sleep Duration and Behavioral Symptoms of Attention-Deficit/Hyperactivity Disorder in Healthy 7- to 8-Year-Old Children

OBJECTIVE. It has been hypothesized that sleep deprivation may manifest in children as behavioral symptoms rather than as tiredness, but only a few studies have investigated this hypothesis. The objective of our study was to evaluate whether short sleep is associated with behavioral symptoms of attention-deficit/hyperactivity disorder in 7- to 8-year-old children. METHODS. We performed a cross-sectional study of children born in 1998 in Helsinki, Finland. The participants included 280 (146 girls, 134 boys) children with a mean age of 8.1 years (SD: 0.3; range: 7.4–8.8). Sleep quality was measured by using actigraphs. The Sleep Disturbance Scale for Children and the Attention-Deficit/Hyperactivity Disorder Rating Scale IV were administered to parents. RESULTS. Children whose average sleep duration as measured by actigraphs was short (<10th percentile, ie, <7.7 hours) and had a higher hyperactivity/impulsivity score (9.7 vs 7.8 or 7.5) and a higher attention-deficit/hyperactivity disorder total score (17.3 vs 14.5 or 13.1) but a similar inattention score (7.6 vs 6.7 or 5.6) compared with children sleeping 7.7 to 9.4 hours or >9.4 hours. In multivariate statistical models, short sleep duration remained a statistically significant predictor of hyperactivity/impulsivity, and sleeping difficulties were associated with hyperactivity/impulsivity, inattention, and the total score. There were no significant interactions between short sleep and sleeping difficulties. CONCLUSIONS. Childrens short sleep duration and sleeping difficulties increase the risk for behavioral symptoms of attention-deficit/hyperactivity disorder.

Very Low Birth Weight and Behavioral Symptoms of Attention Deficit Hyperactivity Disorder in Young Adulthood: The Helsinki Study of Very-Low-Birth-Weight Adults

OBJECTIVE Children with very low birth weight (<1500 g) are at increased risk for attention deficit hyperactivity disorder (ADHD). Whether this increased risk continues into adulthood is unknown. The authors assessed behavioral symptoms of ADHD in a well-characterized cohort of very-low-birth-weight young adults who were either small for gestational age (less than two standard deviations below the Finnish mean) or appropriate for gestational age (within two standard deviations of the mean). METHOD A total of 162 very-low-birth-weight subjects (small for gestational age: N=52; appropriate for gestational age: N=110) and 172 term comparison subjects 18 to 27 years of age completed the Adult Problem Questionnaire, which yielded six exploratory factor analysis-derived subscales. Participants were also asked about substance use. RESULTS Very-low-birth-weight adults in the small for gestational age subgroup scored higher on the executive dysfunctioning and emotional instability subscales of the Adult Problem Questionnaire than did those in the appropriate for gestational age subgroup and the comparison group. The appropriate for gestational age and comparison groups had similar scores on these subscales. On the alcohol use subscale of the Adult Problem Questionnaire, both the appropriate and small for gestational age subgroups scored lower than comparison subjects and also reported fewer risk-taking behaviors (alcohol, smoking, and use of recreational drugs) than did comparison subjects. CONCLUSIONS Rather than very low birth weight per se, intrauterine growth retardation, as reflected by small for gestational age status in the very-low-birth-weight subjects, confers a risk for behavioral and emotional adversity related to ADHD in young adulthood.

Depression in Young Adults With Very Low Birth Weight: The Helsinki Study of Very Low-Birth-Weight Adults

CONTEXT Little is known about the mental health outcomes of very low-birth-weight (VLBW) (< 1500 g) infants in young adulthood. OBJECTIVE To test whether young adults aged 18 to 27 years with VLBW differ from term control subjects in depressive symptoms, current use of antidepressant medication, and the rate of depression diagnosed by a physician. DESIGN Retrospective longitudinal study. SETTING Academic research. PARTICIPANTS A total of 162 VLBW young adults (response rate, 65.1%) and 172 term control subjects (response rate, 54.8%) born between February 22, 1978, and November 8, 1985, in Helsinki, Finland. MAIN OUTCOME MEASURES Antidepressant use, history of physician-diagnosed depression, Beck Depression Inventory score, and Center for Epidemiologic Studies Depression Scale score. RESULTS The VLBW participants reported 20.1% (95% confidence interval [CI], -40.8% to -5.1%) lower CES-D scores than the controls (P =.02). However, this finding was confined to 110 VLBW participants who were born appropriate for gestational age (birth weight > or = -2 SDs according to Finnish birth weight charts), whose Center for Epidemiologic Studies Depression Scale scores were 29.1% (95% CI, -53.7% to -8.4%) lower than those of the controls (P =.004). Furthermore, VLBW participants born appropriate for gestational age were 4.8 (95% CI, 1.3-10.0) times less likely to report a depression diagnosis than controls (P =.02). In contrast, 52 VLBW participants born small for gestational age (birth weight < -2 SDs according to Finnish birth weight charts) reported 36.2% (95% CI, 1.1%-83.5%) higher Beck Depression Inventory scores (P =.04), were 4.0 (95% CI, 1.1-14.3) times more likely to use antidepressants (P =.03), and were 2.5 (95% CI, 1.0-6.3) times more likely to report a depression diagnosis (P =.04) compared with controls. CONCLUSIONS This is the first study (to our knowledge) to show that intrauterine growth pattern may modify associations between VLBW and depression. Intrauterine growth retardation rather than VLBW per se may pose a risk of depression in young adulthood.

Prenatal and postnatal growth and cognitive abilities at 56 months of age: A longitudinal study of infants born at term

OBJECTIVE. The aim of the study was to investigate whether weight, length, BMI (kilograms per meter squared), and head circumference at birth and their postnatal growth are associated with cognitive abilities at 56 months of age among infants born at term. PATIENTS AND METHODS. Our sample was composed of 1056 Finnish children born at term, (37 to 41 weeks) free of any major impairments. Weight, length, and head circumference were measured at birth and at 5, 20, and 56 months of age, and BMI was calculated. We assessed cognitive abilities by conducting tests of general reasoning, visual-motor integration, verbal competence, and language comprehension at 56 months of age. RESULTS. Firstly, for every 1 SD lower in weight or BMI at birth, general reasoning and/or visual-motor integration was >1.20 points lower, and for every 1 SD lower in length or head circumference at birth, abilities across all of the cognitive domains were >1.31 points lower. Second, for every 1 SD slower gain in weight or BMI from birth to 5 months, general reasoning and visual-motor integration decreased by >0.97 points; for every 1 SD slower gain in length from 5 to 20 months and from 20 to 56 months, respectively, visual-motor integration, and verbal competence and language comprehension decreased by >1.03 points; and for every 1 SD slower increase in head circumference from birth to 5 months and from 5 to 20 months, respectively, visual-motor integration and language comprehension decreased by >1.17 points. Third, tests for nonlinear relationships revealed that, in some cases, large body size and faster growth were also associated with lower scores in cognitive tests. CONCLUSIONS. Our findings suggest that, even within the range of children born at term, prenatal and postnatal growth in body size are associated with individual differences in cognitive abilities.

Childhood separation experience predicts HPA axis hormonal responses in late adulthood: A natural experiment of World War II

BACKGROUND Animal models have linked early maternal separation with lifelong changes in hypothalamic-pituitary-adrenocortical (HPA) axis activity. Although this is paralleled in human studies, this is often in the context of other life adversities, for example, divorce or adoption, and it is not known whether early separation in the absence of these factors has long term effects on the HPA axis. AIMS The Finnish experience in World War II created a natural experiment to test whether separation from a father serving in the armed forces or from both parents due to war evacuation are associated with alterations in HPA axis response to psychosocial stress in late adulthood. METHOD 282 subjects (M=63.5 years, SD=2.5), of whom 85 were non-separated, 129 were separated from their father, and 68 were separated from both their caregivers during WWII, were enlisted to participate in a Trier Social Stress Test (TSST), during which we measured salivary cortisol and, for 215 individuals, plasma cortisol and ACTH concentrations. We used mixed models to study whether parental separation is associated with salivary and plasma cortisol or plasma ACTH reactivity, and linear regressions to analyse differences in the baseline, or incremental area under the cortisol or ACTH curves. RESULTS Participants separated from their father did not differ significantly from non-separated participants. However, those separated from both parents had higher average salivary cortisol and plasma ACTH concentrations across all time points compared to the non-separated group. They also had higher salivary cortisol reactivity to the TSST. Separated women had higher baselines in plasma cortisol and ACTH, whereas men had higher reactivity in response to stress during the TSST. Participants who had experienced the separation in early childhood were more affected than children separated during infancy or school age. CONCLUSIONS Separation from parents during childhood may alter an individuals stress physiology much later in adult life.

Behavioural symptoms of attention deficit/hyperactivity disorder in preterm and term children born small and appropriate for gestational age: A longitudinal study

BackgroundIt remains unclear whether it is more detrimental to be born too early or too small in relation to symptoms of attention deficit/hyperactivity disorder (ADHD). Thus, we tested whether preterm birth and small body size at birth adjusted for gestational age are independently associated with symptoms of ADHD in children.MethodsA longitudinal regional birth cohort study comprising 1535 live-born infants between 03/15/1985 and 03/14/1986 admitted to the neonatal wards and 658 randomly recruited non-admitted infants, in Finland. The present study sample comprised 828 children followed up to 56 months. The association between birth status and parent-rated ADHD symptoms of the child was analysed with multiple linear and logistic regression analyses.ResultsNeither prematurity (birth < 37 weeks of gestation) nor lower gestational age was associated with ADHD symptoms. However, small for gestational age (SGA < -2 standard deviations [SD] below the mean for weight at birth) status and lower birth weight SD score were significantly, and independently of gestational age, associated with higher ADHD symptoms. Those born SGA, relative to those born AGA, were also 3.60-times more likely to have ADHD symptoms scores above the clinical cut-off. The associations were not confounded by factors implicated as risks for pregnancy and/or ADHD.ConclusionsIntrauterine growth restriction, reflected in SGA status and lower birth weight, rather than prematurity or lower gestational age per se, may increase risk for symptoms of ADHD in young children.

Poor Sleep and Altered Hypothalamic-Pituitary-Adrenocortical and Sympatho-Adrenal-Medullary System Activity in Children

CONTEXT Neuroendocrine alterations, with well-known links with health, may offer insight into why poor sleep is associated with poor health. Yet, studies testing associations between sleep and neuroendocrine activity in children are scarce. OBJECTIVE The aim of this study was to determine whether actigraphy-based sleep pattern is associated with hypothalamic-pituitary-adrenocortical axis and sympatho-adrenal-medullary system activity in children. DESIGN AND SETTING We conducted a cross-sectional study in a birth cohort in Helsinki, Finland. PARTICIPANTS We studied 282 8-yr-old children. MAIN OUTCOME MEASURES We measured diurnal salivary cortisol and salivary cortisol and alpha-amylase (a sympatho-adrenal-medullary system marker) responses to the Trier Social Stress Test for Children (TSST-C). RESULTS Children with short (<or=7.7 h) vs. average sleep duration (7.8-9.3 h) displayed higher cortisol awakening response and nadir (P < 0.042). Those with low (<or=77.4%) vs. average-high sleep efficiency (>77.4%) displayed higher diurnal cortisol levels across the entire day (P < 0.03), higher cortisol levels after the TSST-C stressor (P < 0.04), and higher overall alpha-amylase levels across the entire TSST-C protocol (P < 0.05). The effects were not confounded by factors that may alter sleep or hormonal patterns. CONCLUSIONS Poor sleep may signal altered neuroendocrine functioning in children. The findings may offer insight into the pathways linking poor sleep with poor health.

Sleep duration and regularity are associated with behavioral problems in 8-year-old children.

BackgroundRelatively little is known about the significance of normal variation in objectively assessed sleep duration and its regularity in childrens psychological well-being.PurposeWe explored the associations between sleep duration and regularity and behavioral and emotional problems in 8-year-old children.MethodsA correlational design was applied among an epidemiological sample of children born in 1998. Sleep was registered with an actigraph for seven nights (range 3 to 14) in 2006. Mothers (n = 280) and fathers (n = 190) rated their childs behavioral problems with the Child Behavior Checklist.ResultsChildren with short sleep duration had an increased risk for behavioral problems, thought problems, and Diagnostic and Statistical Manual of Mental Disorders, 4th Edition-based attention-deficit hyperactivity problems according to maternal ratings. Based on paternal ratings, short sleep duration was associated with more rule-breaking and externalizing symptoms. Irregularity in sleep duration from weekdays to weekends was associated with an increased risk for specifically internalizing symptoms in paternal ratings.ConclusionsThe results highlight the importance of sufficient sleep duration and regular sleep patterns from weekdays to weekends. Short sleep duration was associated specifically with problems related to attentional control and externalizing behaviors, whereas irregularity in sleep duration was, in particular, associated with internalizing problems.

Very Low Birth Weight Increases Risk for Sleep-Disordered Breathing in Young Adulthood: The Helsinki Study of Very Low Birth Weight Adults

OBJECTIVE. We investigated whether very low birth weight (<1500 g) is associated with the risk of sleep-disordered breathing in young adulthood. METHODS. The study was a retrospective longitudinal study of 158 young adults born with very low birth weight and 169 term-born control subjects (aged 18.5–27.1 years). The principal outcome variable was sleep-disordered breathing defined as chronic snoring. RESULTS. The crude prevalence of chronic snoring was similar in both groups: 15.8% for the very low birth weight group versus 13.6% for the control group. However, after controlling for the confounding variables in multivariate logistic regression models (age, gender, current smoking, parental education, height, BMI, and depression), chronic snoring was 2.2 times more likely in the very low birth weight group compared with the control group. In addition, maternal smoking during pregnancy was significantly and independently of very low birth weight related to risk of sleep-disordered breathing. Maternal preeclampsia, standardized birth weight, and, for very low birth weight infants, small-for-gestational-age status were not related to sleep-disordered breathing. CONCLUSIONS. Premature infants with very low birth weight have a twofold risk of sleep-disordered breathing as young adults. In addition, maternal smoking during pregnancy increases the risk of sleep-disordered breathing by more than twofold.

Maintenance of genetic variation in human personality: Testing evolutionary models by estimating heritability due to common causal variants and investigating the effect of distant inbreeding

Personality traits are basic dimensions of behavioral variation, and twin, family, and adoption studies show that around 30% of the between‐individual variation is due to genetic variation. There is rapidly growing interest in understanding the evolutionary basis of this genetic variation. Several evolutionary mechanisms could explain how genetic variation is maintained in traits, and each of these makes predictions in terms of the relative contribution of rare and common genetic variants to personality variation, the magnitude of nonadditive genetic influences, and whether personality is affected by inbreeding. Using genome‐wide single nucleotide polymorphism (SNP) data from > 8000 individuals, we estimated that little variation in the Cloninger personality dimensions (7.2% on average) is due to the combined effect of common, additive genetic variants across the genome, suggesting that most heritable variation in personality is due to rare variant effects and/or a combination of dominance and epistasis. Furthermore, higher levels of inbreeding were associated with less socially desirable personality trait levels in three of the four personality dimensions. These findings are consistent with genetic variation in personality traits having been maintained by mutation–selection balance.