Recalled Experiences of Bullying and Victimization in a Longitudinal, Population-Based Birth Cohort: The Influence of ADHD and Co-Occurring Psychiatric Disorder.

OBJECTIVE: To describe bullying experiences throughout childhood of people with and without childhood ADHD and co-occurring learning and psychiatric disorders from a population-based birth cohort. METHODS: In a secondary data analysis of 199 childhood ADHD cases and 287 non-ADHD referents (N = 486), reported experiences of peer interactions during elementary, middle, or high school were classified as "bully," "victim," "neither," or "both." Associations were assessed with multinomial logistic regression. RESULTS: Adjusted for male sex, the odds of classification as victim-only, victim/bully, or bully- only (vs. neither) were 3.70 (2.36-5.81), 17.71, and 8.17 times higher for childhood ADHD cases compared to non-ADHD referents. Victim-bullies (62.5%) and bullies (64.3%) had both childhood ADHD and other psychiatric disorders versus 38.4% of victims-only and 17.3% of those classified as "neither." CONCLUSION: The list of serious lifetime consequences of having ADHD also includes bullying. We offer future research directions for determining potential causal pathways.

Children With ADHD Are at Risk for a Broad Array of Adverse Adult Outcomes That Cross Functional Domains: Results From a Population-Based Birth Cohort Study.

OBJECTIVE: To identify patterns ("classes") of outcomes for adults with and without childhood ADHD. METHOD: Subjects were 232 childhood ADHD cases and 335 non-ADHD referents from a 1976 to 1982 birth cohort. We used latent class analyses to identify classes based on a broad array of adult psychosocial outcomes and determined the proportion of subjects with childhood ADHD within each class. RESULTS: A three class solution provided optimal model fit; classes were termed "good," "intermediate," and "poor" functioning. Subjects with childhood ADHD comprised 62.8% of the "poor," 53.5% of the "intermediate," and 24.9% of the "good" functioning class. The "poor" functioning class was distinguished by increased likelihood of legal trouble and substance use disorders and included more individuals with childhood ADHD and psychiatric disorder than the "intermediate" class (45.5% vs. 30.6%). CONCLUSION: Children with ADHD are at risk for adverse adult outcomes in multiple domains and co-morbid childhood psychiatric disorders increase risk.

Incidence of Celiac Disease in Down Syndrome: A Longitudinal, Population-Based Birth Cohort Study.

American Academy of Pediatrics (AAP) guidelines for children with Down syndrome (DS) include assessment for celiac disease (CD), although data to support this recommendation have been inconsistent. We determined the incidence of CD among children with DS in a population-based birth cohort of children born from 1976 to 2000 in Olmsted County, Minnesota. Individuals with karyotype-confirmed DS and CD (using diagnosis codes, positive serology, and duodenal biopsies) were identified. The incidence of CD in DS was compared with the published incidence of CD for Olmsted County residents (17.4 [95% confidence interval = 15.2-19.6] per 100 000 person-years). Among 45 individuals with DS from the birth cohort, 3 (6.7%) were identified with positive celiac serology and confirmatory biopsies at ages 9, 12, and 23 years, for an incidence of 325 per 100 000 person-years. Thus, individuals with DS have more than 18 times the incidence rate of CD compared with the general population, supporting the AAP guidelines.

Objective Estimates of Direct-Medical Costs Among Persons Aged 3 to 38 Years With and Without Research-Defined Autism Spectrum Disorder Ascertained During Childhood: A Population-Based Birth-Cohort Study.

OBJECTIVES: Accurate estimates of autism spectrum disorder (ASD)-associated medical costs are essential for predicting future care needs, allocating resources, identifying best practices, and modeling cost-effectiveness. Most existing studies have either employed subjective cost data or ascertained ASD using self-reported or International Classification of Diseases-coded diagnoses. Such ascertainment is especially problematic for identifying milder ASD among older individuals never diagnosed with ASD. METHODS: This 1976 through 2000 population-based birth-cohort study was set in Olmsted County, Minnesota. ASD cases and age- and sex-matched unaffected controls were identified by applying uniform operational research criteria for ASD (using the guidelines of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision) after rigorous review of provider-linked medical and public, private, or home school records available for all members from birth to a maximum age of 21 years. Medical cost estimates for the 901 case-control pairs used line-item provider-linked billing data (including all payers) from 2003 through 2014 (ages 3-38 years). Outpatient pharmaceutical costs were unavailable. Temporal changes in diagnostic criteria, clinical practice, public awareness, and access were addressed by separating analyses into 5-year age group and 4-year calendar period cells. Unadjusted and adjusted (age and age plus co-occurring conditions) cost estimates were provided for cases, controls, and case-control differences. Additional factors (co-occurring conditions, percentage hospitalized, intellectual disability) were investigated using unadjusted descriptive analyses. RESULTS: Cell sample sizes ranged from 93 to 402 for age groups 3 through 19 years and from 45 to 395 for age groups 20 through 38 years. Unadjusted, age-adjusted, and fully adjusted medical costs were significantly higher for cases versus controls in 100% of cells for age groups 3 through 19 years and in 50% (unadjusted), 38% (age adjusted), and 12% (fully adjusted) of cells for age groups 20 through 38 years. CONCLUSIONS: These unique estimates can help inform the construction of cost-effectiveness models; decisions by payers, providers, and policy makers; and predictions of lifetime costs.

Gestational Age, Perinatal Characteristics, and Autism Spectrum Disorder: A Birth Cohort Study.

OBJECTIVE: To determine how gestational age relates to research-identified autism spectrum disorder (ASD-R) in the context of perinatal risk factors. STUDY DESIGN: This is a population-based cohort study using the 1994-2000 Olmsted County Birth Cohort. Children included were born and remained in Olmsted County after age 3 years. ASD-R status was determined from signs and symptoms abstracted from medical and educational records. Cox proportional hazards models were fit to identify associations between perinatal characteristics and ASD-R. RESULTS: The incidence of preterm birth (<37 weeks' gestation) was 8.6% among 7876 children. The cumulative incidence of ASD-R was 3.8% (95% CI 3.3-4.2) at 21 years of age. Compared with children born at full term, the risk of ASD-R appeared to be increased for children born preterm with unadjusted hazard ratios (HRs) of 2.62 (95% CI 0.65-10.57), 1.68 (95% CI 0.54-5.29), and 1.60 (95% CI 1.06-2.40) for children born extremely preterm, very preterm, and moderate-to-late preterm, respectively. In a multivariable model adjusted for perinatal characteristics, the associations were attenuated with adjusted HRs of 1.75 (95% CI 0.41-7.40), 1.24 (95% CI 0.38-4.01), and 1.42 (95% CI 0.93-2.15), for children born extremely preterm, very preterm, and moderate-to-late preterm, respectively. Among children with maternal history available (N = 6851), maternal psychiatric disorder was associated with ASD-R (adjusted HR 1.73, 95% CI 1.24-2.42). CONCLUSIONS: The increased risk of ASD-R among children born preterm relative to children born full term was attenuated by infant and maternal characteristics.

Association of Comorbid Mood and Anxiety Disorders With Autism Spectrum Disorder.

Importance: It is critical to evaluate the risk of comorbid psychiatric diagnoses to meet the needs of individuals with autism spectrum disorder (ASD). Objective: To examine whether individuals with ASD are at greater risk for comorbid diagnoses of depression, anxiety, or bipolar disorder. Design, Setting, and Participants: This cohort study used data from a population-based birth cohort of 31 220 individuals born in Olmsted County, Minnesota, from January 1, 1976, to December 31, 2000. Patients with research-identified ASD were previously identified using a multistep process that evaluated signs and symptoms abstracted from medical and educational records. For each of the 1014 patients with ASD, 2 age- and sex-matched referents who did not meet criteria for ASD were randomly selected from the birth cohort (n = 2028). Diagnosis codes for anxiety, depression, and bipolar disorders were electronically obtained using the Rochester Epidemiological Project records-linkage system. Data analysis was performed from July 1, 2018, to April 1, 2019. Main Outcomes and Measures: Cumulative incidence of clinically diagnosed depression, anxiety, and bipolar disorder through early adulthood in individuals with ASD compared with referents. Results: A total of 1014 patients with ASD (median age at last follow-up, 22.8 years [interquartile range, 18.4-28.0 years]; 747 [73.7%] male; 902 [89.0%] white) and 2028 referents (median age at last follow-up, 22.4 years [interquartile range, 18.8-26.2 years]; 1494 [73.7%] male; 1780 [87.8%] white) participated in the study. Patients with ASD were significantly more likely to have clinically diagnosed bipolar disorder (hazard ratio [HR], 9.34; 95% CI, 4.57-19.06), depression (HR, 2.81; 95% CI, 2.45-3.22), and anxiety (HR, 3.45; 95% CI, 2.96-4.01) compared with referents. Among individuals with ASD, the estimates of cumulative incidence by 30 years of age were 7.3% (95% CI, 4.8%-9.7%) for bipolar disorder, 54.1% (95% CI, 49.8%-58.0%) for depression, and 50.0% (95% CI, 46.0%-53.7%) for anxiety. Among referents, cumulative incidence estimates by 30 years of age were 0.9% (95% CI, 0.1%-1.7%) for bipolar disorder, 28.9% (95% CI, 25.7%-32.0%) for depression, and 22.2% (95% CI, 19.3%-25.0%) for anxiety. Conclusions and Relevance: The findings suggest that individuals with ASD may be at increased risk for clinically diagnosed depression, anxiety, and bipolar disorder compared with age- and sex-matched referents. This study supports the importance of early, ongoing surveillance and targeted treatments to address the psychiatric needs of individuals with ASD.

Patterns of neuropsychological changes after general anaesthesia in young children: secondary analysis of the Mayo Anesthesia Safety in Kids study.

BACKGROUND: We hypothesised that exposure to multiple, but not single, procedures requiring general anaesthesia before age 3 yr is associated with a specific pattern of deficits in processing speed and fine motor skills. METHODS: A secondary analysis (using factor and cluster analyses) of data from the Mayo Anesthesia Safety in Kids study was conducted, in which unexposed, singly exposed, and multiply exposed children born in Olmsted County, MN, USA from 1994 to 2007 were sampled using a propensity-guided approach and underwent neuropsychological testing at ages 8-12 or 15-20 yr. RESULTS: In the factor analysis, the data were well fit to a five factor model. For subjects multiply (but not singly) exposed to anaesthesia, a factor reflecting motor skills, visual-motor integration, and processing speed was significantly lower [standardised difference of -0.35 (95% confidence interval {CI} -0.57 to -0.13)] compared with unexposed subjects. No other factor was associated with exposure. Three groups were identified in the cluster analysis, with 106 subjects (10.6%) in Cluster A (lowest performance in most tests), 557 (55.9%) in Cluster B, and 334 (33.5%) in Cluster C (highest performance in most tests). The odds of multiply exposed children belonging to Cluster A was 2.83 (95% CI: 1.49-5.35; P=0.001) compared with belonging to Cluster B; there was no other significant association between exposure status and cluster membership. CONCLUSIONS: Multiple, but not single, exposures to procedures requiring general anaesthesia before age 3 yr are associated with a specific pattern of deficits in neuropsychological tests. Factors predicting which children develop the most pronounced deficits remain unknown.

Performance on the Operant Test Battery in young children exposed to procedures requiring general anaesthesia: the MASK study.

BACKGROUND: It is not known whether the neurotoxicity produced by anaesthetics administered to young animals can also occur in children. Exposure of infant macaques to ketamine impairs performance in selected domains of the Operant Test Battery (OTB), which can also be administered to children. This study determined whether a similar pattern of results on the OTB is found in children exposed to procedures requiring general anaesthesia before age 3 yr. METHODS: We analysed data from the Mayo Anesthesia Safety in Kids (MASK) study, in which unexposed, singly-exposed, and multiply-exposed children born in Olmsted County, MN, USA, from 1994 to 2007 were sampled using a propensity-guided approach and prospectively underwent OTB testing at ages 8-12 or 15-20 yr, using five tasks that generated 15 OTB test scores. RESULTS: In primary analysis, none of the OTB test scores depended upon anaesthesia exposure status when corrected for multiple comparisons. Cluster analysis identified four clusters of subjects, with cluster membership determined by relative performance on the OTB tasks. There was no evidence of association between exposure status and cluster membership. Exploratory factor analysis showed that the OTB scores loaded onto four factors. The score for one factor was significantly less in multiply-exposed children (mean standardised difference -0.28 [95% confidence interval, -0.55 to -0.01; P=0.04]), but significance did not survive a sensitivity analysis accounting for outlying values. CONCLUSIONS: These findings provide little evidence to support the hypothesis that children exposed to procedures requiring anaesthesia show deficits on OTB tasks that are similar to those observed in non-human primates.

Psychiatric Comorbidities Modify the Association Between Childhood ADHD and Risk for Suicidality: A Population-Based Longitudinal Study.

OBJECTIVE: The objective of this study was to evaluate the effect of psychiatric comorbidities on the association between childhood ADHD and suicidality among adults. METHOD: Subjects were recruited from a population-based birth cohort. Participating adult subjects with childhood ADHD and non-ADHD controls were administered a structured psychiatric interview to assess suicidality and psychiatric comorbidities. Associations were assessed using logistic regression. RESULTS: Compared with controls, ADHD cases were significantly more likely to meet criteria for suicidality. Subjects with childhood ADHD who met criteria for generalized anxiety disorder had a higher than expected risk of suicidality with an observed odds ratio of 10.94 (95% confidence interval [4.97, 24.08]) compared with an expected odds ratio of 4.86, consistent with a synergistic interaction effect. Significant synergistic interactions were also observed for hypomanic episode and substance-related disorders. CONCLUSION: Childhood ADHD is significantly associated with adult suicidal risk. Comorbidity between ADHD and some psychiatric disorders is associated with a higher suicidal risk than expected.

Autism Spectrum Disorder: Incidence and Time Trends Over Two Decades in a Population-Based Birth Cohort.

We retrospectively identified autism spectrum disorder (ASD) incident cases among 31,220 individuals in a population-based birth cohort based on signs and symptoms uniformly abstracted from medical and educational records. Inclusive and narrow research definitions of ASD (ASD-RI and ASD-RN, respectively) were explored, along with clinical diagnoses of ASD (ASD-C) obtained from the records. The incidence of ASD-RI, ASD-RN, and ASD-C increased significantly from 1985 to 1998, then ASD-RI and ASD-RN plateaued while the rate of ASD-C continued to increase during 1998-2004. The rising incidence of research-defined ASD may reflect improved recognition and documentation of ASD signs and symptoms. Although the frequency of threshold ASD symptoms stabilized, the rate of ASD-C continued to increase, narrowing the gap between clinical ascertainment and symptom documentation.

Neuropsychological and Behavioral Outcomes after Exposure of Young Children to Procedures Requiring General Anesthesia: The Mayo Anesthesia Safety in Kids (MASK) Study.

BACKGROUND: Few studies of how exposure of children to anesthesia may affect neurodevelopment employ comprehensive neuropsychological assessments. This study tested the hypothesis that exposure to multiple, but not single, procedures requiring anesthesia before age 3 yr is associated with adverse neurodevelopmental outcomes. METHODS: Unexposed, singly exposed, and multiply exposed children born in Olmsted County, Minnesota, from 1994 to 2007 were sampled using a propensity-guided approach and underwent neuropsychological testing at ages 8 to 12 or 15 to 20 yr. The primary outcome was the Full-Scale intelligence quotient standard score of the Wechsler Abbreviated Scale of Intelligence. Secondary outcomes included individual domains from a comprehensive neuropsychological assessment and parent reports. RESULTS: In total, 997 children completed testing (411, 380, and 206 unexposed, singly exposed, and multiply exposed, respectively). The primary outcome of intelligence quotient did not differ significantly according to exposure status; multiply exposed and singly exposed children scoring 1.3 points (95% CI, -3.8 to 1.2; P = 0.32) and 0.5 points (95% CI, -2.8 to 1.9; P = 0.70) lower than unexposed children, respectively. For secondary outcomes, processing speed and fine motor abilities were decreased in multiply but not singly exposed children; other domains did not differ. The parents of multiply exposed children reported increased problems related to executive function, behavior, and reading. CONCLUSIONS: Anesthesia exposure before age 3 yr was not associated with deficits in the primary outcome of general intelligence. Although secondary outcomes must be interpreted cautiously, they suggest the hypothesis that multiple, but not single, exposures are associated with a pattern of changes in specific neuropsychological domains that is associated with behavioral and learning difficulties.

Epidemiology of general anesthesia prior to age 3 in a population-based birth cohort.

BACKGROUND: Utilization of general anesthesia in children has important policy, economic, and healthcare delivery implications, yet there is little information regarding the epidemiology of these procedures in the United States. AIMS: The primary objective of this study was to describe in a geographically defined population the incidence of procedures requiring general anesthesia up to the child's third birthday, and the patient characteristics associated with receiving these procedures. A secondary objective was to determine the proportion of children in the population who meet the risk criteria promulgated by the Food and Drug Administration (FDA). METHODS: A retrospective cohort of children born from 1994 to 2007 in Olmsted County, MN was established. Birth certificate information and receipt of general anesthesia before age 3 were collected. Proportional hazard regressions were performed to evaluate the association between characteristics of children and incidence of general anesthesia. RESULTS: Among the 20 922 children in the cohort, 3120 (14.9%) underwent at least 1 general anesthesia before age 3. In multivariate regression, factors independently associated with receiving at least 1 procedure included prematurity, male sex, lower birth weight, cesarean delivery, a non-Hispanic mother, and a White mother, controlling for multiple gestation, number of children previously born, age, education, and marital status of the mother. Seven hundred and twenty-three children (3.5%) had at least 1 subsequent procedure. Estimated gestational age <32 weeks and low birth weight were independently associated with receiving repeated anesthesia. Eight hundred and twenty children (3.9%) had a single prolonged exposure above 3 hours, multiple exposures prior to age 3, or both. CONCLUSION: Approximately 1 in 7 children were exposed to at least 1 episode of general anesthesia before age 3, and approximately 1 in 4 children who received general anesthesia fall within the high-risk category as defined by the recent FDA warning. The apparent disparities in surgical utilization related to race and ethnicity in this study population deserve further exploration.

Comparing Methods to Determine Persistence of Childhood ADHD Into Adulthood: A Prospective, Population-Based Study.

OBJECTIVE: To compare the rate of persistence of ADHD into adulthood as determined by a norm-referenced versus non-norm-referenced diagnostic interview, and by standardized questionnaires. METHOD: Adults from a birth cohort, including research-identified childhood ADHD cases ( N = 232; Mage = 27.0 years; 167 males, 65 females) and controls ( N = 335; Mage = 28.6 years; 210 males, 125 females), were administered the M.I.N.I. International Neuropsychiatric Interview, the Murphy-Barkley Symptoms Checklist (MB), and the Wender Utah Rating Scale (WURS) Results: Among the childhood ADHD cases, 29.3% fulfilled criteria for adult ADHD using a norm-referenced approach to M.I.N.I. scoring, versus 13.8% using published M.I.N.I. criteria. Among participants meeting norm-referenced diagnostic criteria, 41.8% and 69.1% were classified as adult ADHD using the MB and WURS, respectively. CONCLUSION: A non-norm-referenced approach resulted in a significant underestimate of the rate of adult ADHD. Reliance on either of two adult ADHD questionnaires would have further reduced this estimate.

Adults With Persistent ADHD: Gender and Psychiatric Comorbidities-A Population-Based Longitudinal Study.

OBJECTIVE: The aim of the study was to evaluate associations between ADHD and comorbid psychiatric disorders among adults from a population-based birth cohort. METHOD: Participants were recruited from all children born between 1976 and 1982 remaining in Rochester, Minnesota, after age 5. Participants with childhood ADHD ( n = 232; M age = 27.0 years; 72% men) and non-ADHD controls ( n = 335; M age = 28.6 years; 63% men) completed a structured interview (M.I.N.I. International Neuropsychiatric Interview) assessing current ADHD status and comorbid psychiatric disorders. RESULTS: Among 232 with childhood ADHD, 68 (49 men, 19 women) had persistent adult ADHD. Compared with non-ADHD controls and non-persistent ADHD participants, adults with persistent ADHD were significantly more likely to have any or each of 12 psychiatric comorbidities. The associations retained significant or marginally significant when stratified by gender. Externalizing psychiatric disorders were more common in men (74%) and internalizing disorders in women (58%). CONCLUSION: Persistent ADHD is associated with an increased risk of comorbid psychiatric disorders in adult men and women.

Association between Exposure of Young Children to Procedures Requiring General Anesthesia and Learning and Behavioral Outcomes in a Population-based Birth Cohort.

BACKGROUND: Exposure of young animals to general anesthesia causes neurodegeneration and lasting behavioral abnormalities; whether these findings translate to children remains unclear. This study used a population-based birth cohort to test the hypothesis that multiple, but not single, exposures to procedures requiring general anesthesia before age 3 yr are associated with adverse neurodevelopmental outcomes. METHODS: A retrospective study cohort was assembled from children born in Olmsted County, Minnesota, from 1996 to 2000 (inclusive). Propensity matching selected children exposed and not exposed to general anesthesia before age 3 yr. Outcomes ascertained via medical and school records included learning disabilities, attention-deficit/hyperactivity disorder, and group-administered ability and achievement tests. Analysis methods included proportional hazard regression models and mixed linear models. RESULTS: For the 116 multiply exposed, 457 singly exposed, and 463 unexposed children analyzed, multiple, but not single, exposures were associated with an increased frequency of both learning disabilities and attention-deficit/hyperactivity disorder (hazard ratio for learning disabilities = 2.17 [95% CI, 1.32 to 3.59], unexposed as reference). Multiple exposures were associated with decreases in both cognitive ability and academic achievement. Single exposures were associated with modest decreases in reading and language achievement but not cognitive ability. CONCLUSIONS: These findings in children anesthetized with modern techniques largely confirm those found in an older birth cohort and provide additional evidence that children with multiple exposures are more likely to develop adverse outcomes related to learning and attention. Although a robust association was observed, these data do not determine whether anesthesia per se is causal.

What can large population-based birth cohort study ask about past, present and future of children with disorders of development, learning and behaviour?

A large cohort consisting of all children born to mothers from community provides 'natural' selection into different exposures and is a powerful resource for epidemiological research. A large population-based birth cohort with detailed systematic information already recorded, as part of longitudinal medical care, historical and current school data, detailed birth certificate data and all three resources available for every member of the birth cohort, are extremely rare. Our population-based birth cohort consists of all children born between 1976 and 2000 to mothers residing in Olmsted County, Minnesota, at the time of child's birth (N=39 890). In this paper, we provide a comprehensive report of the method describing the identification, the characteristics and longitudinal follow-up of each child (and family members) from the birth cohort, wealth of complementary resources of data and study measures and designs (retrospective, combined retrospective/prospective). In the last decade or so, we obtained scientific and clinically needed answers for incidence rates, potential risk/protective factors, treatment, comorbidities, outcomes, cost/usage and potential biases (that are always assessed and clinically interpreted) of many developmental learning and behavioural disorders (DLBDs) including learning and attention-deficit/hyperactivity disorders, intellectual disability, speech-language impairment and autism spectrum disorder. Many current and future questions related to DLBDs are remaining to be answered. The Olmsted County Birth Cohort (OCBC) is an example of a comprehensive, contemporary epidemiological research model for the development of similar research infrastructures, and its current and future results are important for replication and comparison with other population-based retrospective and prospective birth cohort studies.

Epidemiology of Pediatric Critical Illness in a Population-Based Birth Cohort in Olmsted County, MN.

OBJECTIVES: Investigations of pediatric critical illness typically focus on inpatient cohorts drawn from wide referral areas and diverse healthcare systems. Cohorts amenable to investigating the full spectrum of critical illness as it develops within a community have yet to be studied in the United States. Our objective was to provide the first epidemiologic report of the incidence and presentation of pediatric critical illness within a U.S. population-based birth cohort. DESIGN: Retrospective cohort study. SETTING: A geographically defined community (Olmsted, MN) with medical record linkage across all health systems. All ICU services are provided within a single children's hospital. PATIENTS: A birth cohort of children (n =9,441) born 2003-2007 in Olmsted County, MN. MEASUREMENTS AND MAIN RESULTS: During the study period, there were a total of 15,277 ICU admissions to Mayo Clinic Children's Hospital. A total of 577 birth cohort children accounted for 824 of these admissions during the 61,770 person-years of follow-up accumulated. Incidence of first-time ICU admission was 9.3 admits per 1,000 person-years. Admission rates were highest in the first year of life and then declined steadily. Respiratory problems were among the most common reasons for admission at any age and diagnoses reflect changes in health risk factors as children grow and develop over time. After 1 year old, a majority of children admitted have preexisting chronic comorbidities and/or prior ICU stays. In-hospital mortality occurred exclusively in children admitted prior to 5 days of age (n = 4). Seven children died after hospital discharge. CONCLUSIONS: This is the first report characterizing critical illness within a population-based birth cohort of U.S. children. The results demonstrate the changing incidence, presentation, and healthcare requirements associated with critical illness across the developmental spectrum as a population of children ages.

Academic Achievement in Adults with a History of Childhood Attention-Deficit/Hyperactivity Disorder: A Population-Based Prospective Study.

OBJECTIVE: Previous research on the developmental course of attention-deficit/hyperactivity disorder (ADHD) is limited by biased clinic-referred samples and other methodological problems. Thus, questions about adult academic outcomes associated with childhood ADHD remain unanswered. Thus, the objective of this study was to describe academic outcomes in adulthood among incident cases of research-identified childhood ADHD versus non-ADHD referents from a population-based birth cohort. METHOD: Young adults with research-identified childhood ADHD (N = 232; mean age 27.0 yr; 72.0% men) and referents (N = 335; mean age 28.6 yr; 62.7% men) from a 1976 to 1982 birth cohort (N = 5699) were invited to participate in a followup study and were administered an academic achievement battery consisting of the basic reading component of the Woodcock-Johnson III Tests of Achievement (WJ-III) and the arithmetic subtest of the Wide Range Achievement Test-Third Edition (WRAT-3). Outcomes were compared between the 2 groups using linear regression models, adjusted for age, sex, and comorbid learning disability status. RESULTS: Childhood ADHD cases scored from 3 to 5 grade equivalents lower on all academic tests compared with referents, with mean (SD) standard scores of 95.7 (8.4) versus 101.8 (8.1) in basic reading; 95.0 (9.3) versus 101.9 (8.5) in letterword identification; 98.2 (8.6) versus 103.2 (9.2) in passage comprehension; 95.7 (9.1) versus 100.9 (9.0) in word attack; and 87.8 (12.9) versus 98.0 (12.0) in arithmetic. CONCLUSION: This is the first prospective, population-based study of adult academic outcomes of childhood ADHD. Our data provide evidence that childhood onset ADHD is associated with long-term underachievement in reading and math that may negatively impact ultimate educational attainment and occupational functioning in adulthood.

Mediating and Moderating Role of Depression, Conduct Disorder or Attention-Deficit/Hyperactivity Disorder in Developing Adolescent Substance Use Disorders: A Population-Based Study.

OBJECTIVE: To evaluate the mediating/moderating effects of common internalizing /externalizing disorders on the association between ADHD and adolescent substance use disorders (SUD) in a population-based birth cohort. METHODS: Among 5718 children in the birth cohort, 343 ADHD incident cases and 712 matched controls were identified. Psychiatric diagnoses prior to age 19 were classified into DSM-IV categories. The association between ADHD and SUD was summarized (hazard ratios (HR), 95% CI). The effect of depression, CD/ODD, anxiety was evaluated separately. RESULTS: Assessment of the joint effects of ADHD and each psychiatric disorder did not support a moderating effect of these disorders on SUD on additive scale. However, the association between ADHD and SUD was partially explained by a mediating role of these psychiatric disorders. CONCLUSION: For clinicians our results emphasize that depression (or CD/ODD) confers greater risk for SUD than ADHD alone. Early detection/treatment of SUD among adolescents with depression (or CD/ODD) is crucial regardless of ADHD.

Role of individual-housing-based socioeconomic status measure in relation to smoking status among late adolescents with asthma.

PURPOSE: We aimed to assess whether smoking status among individuals in late adolescence (19-22 years) with asthma was associated with socioeconomic status (SES) defined by HOUSES, an individual-housing-based SES measure. METHODS: A population-based cross-sectional study was conducted among the 1988-1989 Olmsted County, Minnesota Birth Cohort, with physician-diagnosed asthma and that lived in the community during the study period (November 1, 2008-October 31, 2012). Using a z score for housing value, actual square footage, and numbers of bedrooms and bathrooms, HOUSES was formulated and categorized into quartiles. Smoking status (both current and past smoker) was compared among subjects with different SES as measured by HOUSES using logistic regression, adjusting for age and sex. RESULTS: Among 289 eligible subjects, 287 (99%) were successfully geo-coded to real property data for HOUSES. Of the 257 subjects whose smoke exposure was recorded, 70 (27%) had a history of smoking (either past or current). An inverse association was observed between HOUSES and smoking status after accounting for age, gender, and General Medical Examination status (adjusted OR = 0.39, 95% CI = 0.18-0.87 for comparing highest vs. lowest HOUSES in quartile; overall P = .02). CONCLUSIONS: A significant proportion of individuals with asthma in late adolescence was smokers during the study period, disproportionally affecting those with lower SES.