Population-based Birth Cohort Research Articles

Congenital anomalies associated with oil and gas development and resource extraction: a population-based retrospective cohort study in Texas.

Oil and gas extraction-related activities produce air and water pollution that contains known and suspected teratogens. To date, health impacts of in utero exposure to these activities is largely unknown. We investigated associations between in utero exposure to oil and gas extraction activity in Texas, one of the highest producers of oil and gas, and congenital anomalies. We created a population-based birth cohort between 1999 and 2009 with full maternal address at delivery and linked to the statewide congenital anomaly surveillance system (n = 2,234,138 births, 86,315 cases). We examined extraction-related exposures using tertiles of inverse distance-squared weighting within 5 km for drilling site count, gas production, oil production, and produced water. In adjusted logistic regression models, we calculated odds of any congenital anomaly and 10 specific organ sites using two comparison groups: 1) 5 km of future drilling sites that are not yet operating (a priori main models), and 2) 5-10 km of an active well. Using the temporal comparison group, we find increased odds of any congenital anomaly in the highest tertile exposure group for site count (OR: 1.25; 95% CI: 1.21, 1.30), oil production (OR: 1.08; 95% CI: 1.04, 1.12), gas production (1.20; 95% CI: 1.17, 1.23), and produced water (OR: 1.17; 95% CI: 1.14, 1.20). However, associations did not follow a consistent exposure-response pattern across tertiles. Associations are highly attenuated, but still increased, with the spatial comparison group in the highest tertile exposure group. Cardiac and circulatory defects are strongly and consistently associated with all exposure metrics. Increased odds of congenital anomalies, particularly cardiac and circulatory defects, were associated with exposures related to oil and gas extraction in this large population-based study. Future research is needed to confirm findings, examine specific exposure pathways, and identify potential avenues to reduce exposures among local populations. About 5% of the U.S. population (~17.6 million people) resides within 1.6 km of an active oil or gas extraction site, yet the influence of this industry on population health is not fully understood. In this analysis, we examined associations between oil and gas extraction-related exposures and congenital anomalies by organ site using birth certificate and congenital anomaly surveillance data in Texas (1999-2009). Increased odds of congenital anomalies, particularly cardiac and circulatory defects, were associated with exposures related to oil and gas extraction in this large population-based study. Future research is needed to confirm these findings.

Smartphone-based long-term delayed memory performance is associated with the Preclinical Alzheimer's Cognitive Composite and CSF levels of β-amyloid.

Remote and unsupervised cognitive testing using smartphones may improve sensitivity to detect preclinical Alzheimer's disease (AD). In particular, cognitive testing at-home enables the evaluation of the potentially more sensitive long-term delayed memory retrieval, which is commonly not feasible in a clinical setting. Here, we investigated the association between remote and unsupervised smartphone-based cognitive assessments and in-clinic cognitive measurement in older participants (CDR = 0, MMSE = 29.2, age = 77). The sample (non-demented at age 70) was derived from the Swedish population-based Gothenburg H70 Birth Cohort Studies. In a subsample of participants, the retrospective correlation with cerebrospinal fluid (CSF) biomarkers analyzed at age 70 was further explored. To this point, 177 H70-participants have consented and were enrolled into the smartphone sub-study. They completed an "Object-in-Room Recall Test" (ORR) remotely and unsupervised using own mobile devices, and the recall session was initiated 24 hours after the initial learning phase. Available previously assessed CSF measures included the Aβ42/Aβ40-ratio, t-tau, p-tau, neurofilament light (NFL), and neurogranin, available in-clinic cognitive tests included the Rey Auditory Verbal Learning Test (RAVLT), Semantic Fluency, Digit-Symbol-Coding, and Mini Mental State Examination. The above-mentioned cognitive tests were used to derive the Preclinical Alzheimer's Cognitive Composite (PACC5), a composite designed to be sensitive to cognitive change in preclinical AD. All associations were examined using Pearson correlation coefficient. Preliminary analyses in a subset of participants yielded relatively strong positive correlations between PACC5 (R = .50, p<.001) and the ORR Long-term Delayed Retrieval. The strongest correlation for an individual test was observed between the RAVLT Delayed Retrieval and the ORR Long-term Delayed Retrieval (R = .52, p<.001). Regarding the CSF biomarkers, Aβ42/Aβ40-ratio at age 70 was positively correlated with the ORR Long-term Delayed Retrieval at age 77 (R = .43, p<.01), while measures of t-tau, p-tau, NFL, and neurogranin at age 70 were not. Our findings demonstrate the potential of smartphone-based cognitive assessment to detect features of preclinical AD in a population-based sample of older adults. Future analyses will address the relationship between these novel cognitive measures in relation to longitudinal CSF- and neuroimaging-based biomarkers and clinical progression.

The association between breastfeeding and childhood obesity/underweight: a population-based birth cohort study with repeated measured data

BackgroundThe impact of breastfeeding on childhood obesity has long been under debate, with most research showing significant association, and others showing weak or no association between breastfeeding and childhood obesity. What’s more, almost all of the previous studies focused on the association between breastfeeding and childhood obesity, and no studies have assessed the association between breastfeeding and childhood underweight.This study aimed to examine the association between breastfeeding and childhood obesity as well as childhood underweight from 1 to 6 years old.MethodsA retrospective population-based cohort study of 59,564 children born between May 2009 and April 2013 in China was conducted using the healthcare records data from the Tianjin Maternal and Child Healthcare System. Information on infant breastfeeding (exclusive breastfeeding, mixed feeding, and exclusive formula feeding) within 6 months old and childhood growth (6 times of repeated measured weight and height from 1 to 6 years old) was collected. Multinomial logistic regression was used to test the potential associations between infant feeding modalities and childhood growth (underweight, normal weight and obesity).ResultsCompared with exclusive formula feeding, breastfeeding was inversely associatied with childhood obesity from 2 to 6 years old, and there was a trend from mixed feeding to exclusive breastfeeding (Ptrend < 0.05). The largest association with obesity was displayed at 3 years old, with the multivariable adjusted odds ratios (ORs) for exclusive formula feeding, mixed feeding and exclusive breastfeeding of 1.00, 0.62 (95% CI 0.49, 0.80) and 0.57 (95% CI 0.44, 0.74) (Ptrend = 0.001), respectively. Compared with exclusive breastfeeding, exclusive formula feeding may increase the risk of childhood underweight at 3 and 5 years old.ConclusionsBreastfeeding was inversely associated with the risk of childhood obesity from 2 to 6 years old, and there was a trend from mixed feeding to exclusive breastfeeding. Infant exclusive formula feeding might be a risk factor for childhood underweight at preschool time.

In utero Exposure to Maternal Diabetes and the Risk of Cerebral Palsy: A Population-based Cohort Study.

Evidence on the effects of in utero exposure to maternal diabetes on cerebral palsy (CP) in offspring is limited. We aimed to examine the effects of pregestational (PGDM) and gestational diabetes (GDM) separately on CP risk and the mediating role of increased fetal size. In a population-based study, we included all live births in Ontario, Canada, between 2002 and 2017 followed up through 2018 (n = 2,110,177). Using administrative health data, we estimated crude and adjusted associations between PGDM or GDM and CP using Cox proportional hazards models to account for unequal follow-up in children. For the mediation analysis, we used marginal structural models to estimate the controlled direct effect of PGDM (and GDM) on the risk of CP not mediated by large-for-gestational age (LGA). During the study period, 5,317 children were diagnosed with CP (187 exposed to PGDM and 171 exposed to GDM). Children of mothers with PGDM showed an increased risk (hazard ratio [HR]: 1.84 [95% confidence interval (CI): 1.59, 2.14]) after adjusting for maternal sociodemographic and clinical factors. We found no associations between GDM and CP (adjusted HR: 0.91 [0.77, 1.06]). Our mediation analysis estimated that LGA explained 14% of the PDGM-CP association. In this population-based birth cohort study, maternal pregestational diabetes was associated with increased risk of CP, and the increased risk was not substantially mediated by the increased fetal size.

In Utero Exposure to Maternal Injury and the Associated Risk of Cerebral Palsy

Although maternal unintentional injury during pregnancy has shown negative impacts on the mother and fetus, the evidence on its long-term associations with children's neurodevelopment is limited. To examine the association between maternal unintentional injury and cerebral palsy (CP) in offspring. This was a population-based, longitudinal, cohort study of all in-hospital live births born between April 1, 2002, and March 31, 2017, in a publicly funded health care system setting of Ontario, Canada. Infants born more than 20 weeks' gestation were included and followed up until March 31, 2018. Excluded from the analysis were stillbirths, infants with missing or invalid records, and births with missing or invalid birth characteristics. Data were analyzed from March 1 to June 30, 2021. Maternal unintentional injury during pregnancy ascertained based on inpatient or emergency department diagnoses. CP diagnosis between birth and the end of follow-up in 2018 with the CP case definition of a single inpatient or 2 or more outpatient diagnoses at least 2 weeks apart between birth and age 16 years. Of 2 110 177 children included in this study (mean [SD] gestational age, 38.8 [1.9] weeks; 1 082 520 male [51.3%]), 81 281 (3.9%) were exposed in utero to maternal unintentional injury. During a median (IQR) follow-up time of 8 (4-12) years, 5317 children (0.3%) were diagnosed with CP (292 CP cases [5.5%] were exposed to maternal unintentional injury). The mean incidence rates of CP were 4.36 and 2.93 per 10 000 child-years in the exposed and the unexposed group, respectively. Children exposed to maternal unintentional injury had a modest increase in the risk of CP, compared with those unexposed (hazard ratio [HR], 1.33; 95% CI, 1.18-1.50) after adjusting for maternal sociodemographic and clinical characteristics. Severe injuries that resulted in hospitalization and delivery within 1 week from the injury conferred higher risks of CP (adjusted HR, 2.18; 95% CI, 1.29-3.68 and adjusted HR, 3.40; 95% CI, 1.93-6.00, respectively). Results were robust in multiple bias analyses. In this Canadian population-based birth cohort study, in utero exposure to maternal unintentional injury was associated with an increased risk of CP, with a higher risk with more severe injuries. These findings fill an important gap in knowledge on the potential role of maternal injury on children's neurodevelopment outcomes. Public health professionals and stakeholders should be aware of these potential long-term consequences on offspring when designing programs and providing recommendations about safety during pregnancy. Early monitoring and developmental assessment of children exposed to maternal injury might be warranted.

Childhood Trauma As a Mediator of the Association Between Autistic Traits and Psychotic Experiences: Evidence From the Avon Longitudinal Study of Parents and Children Cohort.

Little is known on whether associations between childhood autistic traits and psychotic experiences persist into adulthood and whether genetic confounding and childhood trauma influence them. Here we investigate the associations between childhood autistic traits and psychotic experiences until young adulthood and assess the influence of schizophrenia polygenic risk and childhood traumatic experiences, using the Avon Longitudinal Study of Parents and Children (ALSPAC) population-based birth cohort. We used a measure of broad autistic traits (autism factor mean score), and four dichotomised measures of autistic traits capturing social communication difficulties (age 7), repetitive behaviours (age 5), sociability (age 3), and pragmatic language (age 9). Psychotic experiences were assessed at ages 18 and 24 using the semi-structured Psychosis-Like Symptoms interview (PLIKSi). Traumatic experiences between ages 5 and 11 were assessed with questionnaires and interviews administered to children and parents at multiple ages. Broad autistic traits, as well as social communication difficulties, were associated with psychotic experiences that were distressing and/or frequent until age 24 (autism factor mean score, n = 3707: OR 1.19, 95%CI 1.01-1.39; social communication difficulties, n = 3384: OR 1.54, 95%CI 0.97-2.45). Childhood trauma mediated a substantial proportion of the identified associations (~28% and 36% respectively, maximum n = 3577). Schizophrenia polygenic risk did not appear to confound the associations. Multiple imputation analyses (maximum n = 13 105) yielded comparable results. Childhood trauma may be an important, potentially modifiable pathway between autistic features and later onset of psychotic psychopathology.

Social inequalities in child development: the role of differential exposure and susceptibility to stressful family conditions

BackgroundStressful family conditions may contribute to inequalities in child development because they are more common among disadvantaged groups (ie, differential exposure) and/or because their negative effects are stronger among disadvantaged...

Plasticity of Individual Lung Function States from Childhood to Adulthood.

Rationale: Recent evidence highlights the importance of optimal lung development during childhood for health throughout life. Objectives: To explore the plasticity of individual lung function states during childhood. Methods: Prebronchodilator FEV1 z-scores determined at age 8, 16, and 24 years in the Swedish population-based birth cohort BAMSE (Swedish abbreviation for Child [Barn], Allergy, Milieu, Stockholm, Epidemiological study) (N = 3,069) were used. An unbiased, data-driven dependent mixture model was applied to explore lung function states and individual state chains. Lung function catch-up was defined as participants moving from low or very low states to normal or high or very high states, and growth failure as moving from normal or high or very high states to low or very low states. At 24 years, we compared respiratory symptoms, small airway function (multiple-breath washout), and circulating inflammatory protein levels, by using proteomics, across states. Models were replicated in the independent Dutch population-based PIAMA (Prevention and Incidence of Asthma and Mite Allergy) cohort. Measurements and Main Results: Five lung function states were identified in BAMSE. Lung function catch-up and growth failure were observed in 74 (14.5%) BAMSE participants with low or very low states and 36 (2.4%) participants with normal or high or very high states, respectively. The occurrence of catch-up and growth failure was replicated in PIAMA. Early-life risk factors were cumulatively associated with the very low state, as well as with catch-up (inverse association) and growth failure. The very low state as well as growth failure were associated with respiratory symptoms, airflow limitation, and small airway dysfunction at adulthood. Proteomics identified IL-6 and CXCL10 (C-X-C motif chemokine 10) as potential biomarkers of impaired lung function development. Conclusions: Individual lung function states during childhood are plastic, including catch-up and growth failure.

Validity of partial protocols to evaluate the prevalence of developmental defects of enamel in permanent dentition: a birth cohort study in Southern Brazil.

To evaluate the validity of partial protocols (PP) to assess the prevalence of developmental defects of enamel (DDE) in permanent teeth and identify the strength of the association between DDE and some risk factors, using PP compared to the full-mouth (FM) exam. This study was conducted in a population-based birth cohort of children born in 2004 in Pelotas, Southern Brazil. Socioeconomic, demographic, pre-, per-, and post-birth variables were collected. A subsample of 994 children was clinically examined for DDE in 2017, using the modified DDE index, using the "full- mouth" (FM) protocol. After FM had been performed, a dataset was created. Two different partial protocols (PP) were simulated from FM data: "only buccal surfaces (BS)" and "incisive and molars only (IM)." Sensitivity, absolute and relative bias, and inflation factors were calculated. For any DDE, FM had prevalence of 40.8%. The prevalence of DDE was 38.8% and 36.0%, for BS and IM protocols, respectively. When tested for any DDE, PP "BS" and "IM" showed high sensitivity. The underestimation of the true prevalence did not exceed 6.9% for PP "BS" and 16.1% for PP "IM." All protocols showed similar magnitude of association with the selected risk factors. Both PP "BS" and "IM" can be used to estimate the prevalence of DDE in epidemiological studies. Oral health surveys now have the option of using PP to collect DDE prevalence and investigate their association with risk factors, being less time-consuming, expensive, and labor intensive.

Air pollution during the perinatal period and neurodevelopment in children: A national population study in Taiwan.

To evaluate the association between ambient particulate matter no larger than 2.5 μm in diameter (PM2.5 ) during the prenatal and postnatal periods and infant neurodevelopmental parameters. We conducted a population-based birth cohort study using the Taiwan Birth Cohort Study. Participants were assessed for developmental conditions through home interviews at 6 months and 18 months of age. Exposure to PM2.5 of mothers and infants during perinatal periods was estimated using hybrid kriging/land-use regression. The exposure was linked to each participant by home address. Logistic regression was then conducted to determine the risk of neurodevelopmental delay in relation to PM2.5 . A total of 17 683 term singletons without congenital malformations were included in the final analysis. PM2.5 during the second trimester was associated with increased risks of delays in gross motor neurodevelopmental milestones (adjusted odds ratio [aOR] 1.09 per 10 μg/m3 increase in exposure to PM2.5 ). Delayed fine motor development was also found to be related to exposure to PM2.5 in the second and third trimesters (aOR 1.06), as was personal-social skill (aOR 1.11 for the second trimester and 1.06 for the third). These neurodevelopmental parameters were unrelated to postnatal PM2.5 exposure. Exposure to ambient PM2.5 during pregnancy was significantly related to delay in gross motor, fine motor, and personal-social development in this population-based study. Prenatal exposure to higher PM2.5 was associated with increased risk of delayed early neurodevelopment. The critical period for delayed gross motor development was the second trimester. The critical period for fine motor and personal-social development was the second and third trimesters.

Risk factors for natural menopause before the age of 45: evidence from two British population-based birth cohort studies

BackgroundMenopause that occurs before the age of 45 and is not medically induced (referred to here as ‘early natural menopause’) affects around one in 10 women and has serious health consequences. These consequences include increased risk of all-cause mortality, cardiovascular disease, osteoporosis, and type 2 diabetes.MethodsWe investigate risk factors for the onset of natural menopause before the age of 45 in two population-based prospective cohort studies in Britain: the 1958 cohort following 8959 women and the 1970 cohort following 8655 women. These studies follow women from birth to adulthood, and we use harmonized data on birth and early life characteristics, reproductive health, health behaviour, and socioeconomic characteristics for 6805 women who were pre-menopausal, peri-menopausal or had undergone natural menopause. Of these 6805 women, 3614 participated in the 1958 cohort (of which 368 had early menopause) and 3191 participated in the 1970 cohort (of which 206 had early menopause). Taking a life course approach, we focus on three distinct life stages - birth/early life, childhood, and early adulthood - to understand when risk factors are most harmful. Respecting the temporal sequence of exposures, we use a series of multivariable logistic regression models to estimate associations between early menopause and each potential risk factor adjusted for confounders.ResultsWe find that early menopause is influenced by circumstances at birth. Women born in lower social class families, whose mother smoked during the pregnancy or who were breastfed 1 month or less were more likely to undergo early menopause. Early menopause is also associated with poorer cognitive ability and smoking in childhood. Adult health behaviour also matters. Smoking is positively correlated with early menopause, while regular exercise and moderate frequency of alcohol drinking in women’s early thirties are associated with reduced risk of early menopause. The occurrence of gynaecological problems by women’s early thirties is also linked to early menopause.ConclusionsWe demonstrate that characteristics at different periods of life are associated with early menopause. Some of these associations relate to modifiable behaviours and thus the risks of early menopause and the adverse health outcomes associated with it may be preventable.

Nationwide Incidence of Infantile Cataract Surgery and Risk of Secondary Glaucoma in a Population-based Birth Cohort

To determine the nationwide birth cohort incidence of infantile cataract (IC) surgery and the risk of secondary glaucoma in a Korean population. A population-based, retrospective cohort study. We accessed the Korean National Health Claims database to identify patients with IC who were diagnosed before 1 year of age and who underwent IC surgery among all Koreans born between 2008 and 2018 (n=9,593,003). We estimated IC surgery incidence in a birth cohort. The incidence rates of post-IC surgery glaucoma were estimated per 100 person-years, based on the Poisson distribution. The risk factors for post-IC surgery glaucoma, including ophthalmic and systemic comorbidities, were analyzed by multivariable logistic regression analysis. During the 11-year study period, 692 patients underwent IC surgery. The annual birth cohort incidence of IC surgery in the general population ranged from 5.10 to 9.29 cases per 100,000 individuals. Among patients who had been followed up for longer than 1 year (n=650), 92 (14.2%) developed glaucoma, and its incidence rate was 2.29 (95% confidence interval, 1.86-2.80) per 100 person-years. The mean time from IC surgery to glaucoma development was 4.7 ± 3.5 years. No factors were identified as being associated with post-IC surgery glaucoma risk other than primary or secondary intraocular lens implantation, which reduces the risk (all P < .05). In patients without primary intraocular lens implantation, the risk of glaucoma increased steeply during the first 2 years after IC surgery. This study identified the birth cohort incidence of IC surgery and secondary glaucoma risk in individuals of East Asian ethnicity. These estimates may help to better understand the epidemiologic features and clinical courses of patients with IC.

Gestational weight gain and breastfeeding practices in relation to offspring body mass index among Amazonian young children.

Excessive weight gain during childhood has been considered an early life risk factor for chronic disease in the long term. We examined the role of excessive gestational weight gain (GWG) and breastfeeding (BF) practices with the offspring's body mass index-for-age z-score (zBMI) at 2 years. Data from 743 Amazonian young children of the MINA-Brazil population-based birth cohort study were used. Linear regression models were run to estimate the associations between excessive GWG and BF practices (exclusive breastfeeding, EBF <3months of age and BF <1year) with zBMI. Excessive GWG and BF <1year were associated with an adjusted 0.24 units (95% CI: 0.08, 0.41) and 0.28 units (95% CI: 0.12, 0.44) higher zBMI at age 2 years, respectively. Gain excessive weight during pregnancy and shorter BF duration (<1y) were associated with a higher body mass index at 2 years of age among Brazilian Amazonian children.

Incidence and risk of attention-deficit/hyperactivity disorder and learning disability by adulthood after traumatic brain injury in childhood: a population-based birth cohort study

ABSTRACT The aim of this study was to understand the risk of developing attention-deficit/hyperactivity disorder (ADHD) or learning disability (LD) after childhood traumatic brain injury (TBI) in a population-based birth cohort. Cases of TBI for children from birth to 10 years were confirmed and stratified by severity of injury. For each TBI case, two age-matched and sex-matched referents without TBI were identified from the same birth cohort. Presence of ADHD and LD before age 19 were confirmed using medical and/or school records. Associations between TBI exposure and subsequent ADHD or LD were assessed in multivariable Cox regression models, adjusting for maternal age, education, and race. The incidence rate of TBI before age 10 was 1,156 per 100,000 person-years. Children who had a TBI before age 10 were more likely to have met the research criteria for ADHD (hazard ratio [HR], 1.68; 95% CI, 1.15–2.45) or LD (HR, 1.29; 95% CI, 1.00–1.68) by age 19. No statistically significant associations were shown between TBI and ADHD or LD when restricted to definite and probable TBI cases (consistent with moderate to severe and mild TBI, respectively) and their referents. Significant associations were shown when the analysis was confined to possible TBI cases (consistent with concussive TBI) and their referents (ADHD: HR, 2.05; 95% CI, 1.31–3.20; and LD: HR, 1.42; 95% CI, 1.05–1.91). Increased risk for developing ADHD and LD by adulthood was shown particularly for children with the least-severe injuries, indicating that factors other than trauma-related altered brain function likely contribute to this risk.

Health-related quality of life among five-year-old extremely preterm children with motor disorders

Abstract Background Motor disorders resulting from extremely preterm birth (EPT; &amp;lt;28 weeks’ gestation) can limit daily activities, schooling and social relationships. Cerebral palsy (CP) affects about 10% of children and non-CP movement difficulties (MD) are highly prevalent, although they tend to be under-diagnosed, especially in children without other developmental difficulties. We investigated the association between motor disorders and health-related quality of life (HRQoL) among five-year-old children born EPT. Methods We included children at age five from a population-based EPT birth cohort born in 2011-2012 in 11 European countries (N = 1,021). Children without CP were classified using the Movement Assessment Battery for Children - 2nd edition as having significant MD (≤5th percentile of standardised norms) or being at risk of MD (6th-15th percentile). Parents reported on CP diagnoses and HRQoL using the Pediatric Quality of Life InventoryTM. We used linear regression to compare HRQoL scores by motor status adjusting for social characteristics. Results Children born EPT with CP, significant MD and at risk of MD had lower adjusted HRQoL total scores [95% confidence intervals] than those without MD: -26.1 [-31.0; -21.2], -9.1 [-12.0; -6.1] and -5.0 [-7.7; -2.3]. Decreases were greater for physical scores: -35.3 [-42.7; -27.9], -11.9 [-16.1; -7.8] and -5.4 [-9.1; -1.6] than psychosocial scores: -20.6 [-25.2; -16.0], -7.4 [-10.3; -4.5] and -4.9 [-7.6; -2.1]. These differences persisted after exclusion of children with other developmental difficulties. Conclusions Motor disorders among 5-year-old children born EPT were associated with lower HRQoL, even among children with less severe motor difficulties and without other developmental difficulties. Key messages

Predicting low cognitive ability at age 5 using machine learning methods and birth cohort data

Abstract Background Early intervention is essential to address disparities in cognitive development. Current developmental screening will not detect the vast majority of children who go on to have below average cognitive ability at school age. In this study, we applied the random forest (RF) algorithm, a highly interpretable machine learning method, to birth-cohort data to train a model to predict low cognitive ability at 5 years of age using perinatal features. Methods Data was from 1,070 participants in the Irish population-based BASELINE birth cohort. A RF model was trained to predict an intelligence quotient (IQ) score &amp;lt;90 at age 5 years using a broad selection of maternal, infant, birth, and sociodemographic features, all of which could be easily measured at a population level in the perinatal period. Feature importance was examined using mean decrease in Gini impurity, mean decrease in accuracy, and mean minimal depth. Recursive feature elimination was used to develop a parsimonious model. Internal validation was performed using 10-fold cross validation repeated 5 times. Results The most predictive features for low cognitive ability at 5 years of age were the total years of maternal schooling, infant Apgar score at 1 minute, socioeconomic index, maternal BMI, and units of alcohol consumed in the first trimester. A parsimonious RF model based on 11 features showed excellent predictive ability, with a sensitivity of 0.89 and a specificity of 0.98, providing a foundation suitable for external validation in an unseen cohort. Conclusions Machine learning approaches to large existing datasets can provide accurate feature selection to improve risk prediction. Further validation of this model is required in additional cohorts, representative of the general population. Accurate risk prediction can facilitate targeted screening and intervention. Key messages • The application of machine learning to large population-based data can improve feature selection and accuracy in risk prediction models. • Accurate risk prediction may enable early intervention to address disparities in cognitive development. Individual interventions must occur in conjunction with population level policy changes.

Do preventive child examinations in general practice reduce the risk of overweight and obesity?

Abstract Background The prevalence of children with overweight and obesity is increasing. General practitioners in Denmark follow children throughout early childhood via the preventive child health examinations. These examinations are offered to all children from birth to the age of five. Thus, the general practitioners have a unique opportunity for early tracing and identification of overweight and obesity, but the impact of the examinations are not examined. Therefore, the aim of this study was to examine the association between attending preventive child health examinations and the risk of overweight and obesity at the age of six both for the total pediatric population and within groups of vulnerable children such as children of parents with low educational level or low household income. Methods A population-based birth cohort study was conducted including all Danish children born from 2000-2012 using the Danish nationwide registers. Data included information on child participation in preventive health examinations at general practice, height and weight at the age of six, and parental information on socioeconomic factors. Results The analyses included 801,444 children. Attending preventive child health examinations were not associated with a lower risk of overweight at the age of six. A lower risk of obesity was seen in children attending the examinations, both in the general population (RR 0.71, 95% CI 0.66-0.76) and within vulnerable groups (low level of maternal education: RR 0.80, 95% CI 0.72-0.89), low household income (RR 0.79, 95% CI 0.72-0.87). The risk of obesity was greater in the vulnerable groups than in the not-vulnerable groups. Conclusions Attending preventive child health examinations were associated with a lower risk of obesity at the age of six, but not overweight. This was seen for both the general pediatric population and within vulnerable groups. The lowest risk of obesity was seen in the not-vulnerable groups. Key messages • The results indicated that attending preventive child health examinations in general practice reduced the risk of obesity at the age of six, but not the risk of overweight. • The lowest risk of obesity was seen in the not-vulnerable groups attending the preventive child health examinations in general practice.

Fetal thoracic circumference in mid-pregnancy and infant lung function.

Impaired lung function in early infancy is associated with later wheeze and asthma, while fetal thoracic circumference (TC) predicts severity of neonatal lung hypoplasia. Exploring fetal origins of lung function in infancy, we aimed to determine if fetal TC in mid-pregnancy was associated with infant lung function. From the prospective Scandinavian general population-based PreventADALL mother-child birth cohort, all 851 3-month-old infants with tidal flow-volume measurements in the awake state and ultrasound fetal size measures at 18 (min-max 16-22) weeks gestational age were included. Associations between fetal TC and time to peak tidal expiratory flow to expiratory time (tPTEF /tE ) were analyzed in linear regression models. To account for gestational age variation, we adjusted TC for simultaneously measured general fetal size, by head circumference (TC/HC), abdominal circumference (TC/AC), and femur length (TC/FL). Multivariable models were adjusted for maternal age, maternal asthma, pre-pregnancy body mass index, parity, nicotine exposure in utero, and infant sex. The infants (47.8% girls) were born at mean (SD) gestational age of 40.2 (1.30) weeks. The mean (SD) tPTEF /tE was 0.39 (0.08). The mean (SD) TC/HC was 0.75 (0.04), TC/AC0.87 (0.04),and TC/FL 4.17 (0.26), respectively. Neither TC/HC nor TC/AC were associated with infant tPTEF /tE while a week inverse association was observed between TC/FL and tPTEF /tE ( = -0.03, 95% confidence interval [-0.05, -0.007], p = 0.01). Mid-pregnancy fetal TC adjusted for fetal head or abdominal size was not associated with tPTEF /tE in healthy, awake 3-month-old infants, while a weak association was observed adjusting for fetal femur length.

School Performance and Young Adult Crime in a Brazilian Birth Cohort

Poor school performance may increase the risk of crime and violence via effects on self-esteem, risky behaviours, peer networks, and perceived stakes in society. Despite very high rates of violence in Latin America, no longitudinal research has addressed this issue in the region. Two aspects of educational performance (grade repetition and school completion) were examined during adolescence in a population-based Brazilian birth cohort study (n = 3584). Violent and non-violent crime were measured at age 22 years in confidential self-reports; sociodemographic, family, and individual confounders were measured between birth and age 11 years, and potential mediators were measured at age 18 years. The prevalence of violent and non-violent crimes at 22 years was 8.2% and 3.3%, respectively, referring to acts in the previous twelve months. For youth repeating school grades three times or more, the odds of violent crime were 2.4 (95%CI: 1.6–3.6) times higher than for those who had not repeated any school grade. Youth completing school had a lower risk for both violent (OR = 0.5; 95%CI: 0.4–0.7) and non-violent crime (OR = 0.3; 95%CI: 0.2–0.5), compared to those who did not finish school by the expected age. The protective effect of completing school was independent of the number of grades previously repeated. In conclusion, repeating school grades was associated with increased risk for crime; however, successfully managing to complete school by the expected age was an important protective factor against crime, even after multiple grade repetitions.

Specific adolescent prodromal symptoms associated with onset of psychosis in the Northern Finland Birth Cohort 1986.

Several psychological symptoms in adolescence associate with later development of psychosis. However, it is unclear which symptoms specifically predict psychotic disorders rather than psychiatric disorders in general. We conducted a prospective study comparing how specific adolescent psychotic-like symptoms, predicted psychotic and non-psychotic hospital-treated psychiatric disorders in the population-based Northern Finland Birth Cohort 1986 (NFBC1986). At age 15-16 years, 6632 members of the NFBC1986 completed the PROD-screen questionnaire. New hospital-treated mental disorders of the NFBC1986 participants were detected between age 17 and 30 years from the Finnish Care Register for Health Care. Multiple covariates were used in the analysis. During the follow-up, 1.1% of the participants developed a psychotic and 3.2% a non-psychotic psychiatric disorder. Three symptoms were specifically associated with onset of psychosis compared to non-psychotic psychiatric disorders: 'Difficulty in controlling one's speech, behaviour or facial expression while communicating' (adjusted OR 4.00; 95% CI 1.66-9.92), 'Difficulties in understanding written text or heard speech' (OR 2.25; 1.12-4.51), and 'Difficulty or uncertainty in making contact with other people' (OR 2.20; 1.03-4.67). Of these, the first one remained statistically significant after Bonferroni correction for multiple comparisons. To our knowledge, this is the first general-population-based prospective study exploring psychiatric symptoms predicting the onset of hospital-treated first-episode psychosis in comparison to non-psychotic disorders. We found three symptoms related with difficulties in social interaction which predicted onset of psychosis. This is a novel finding and should be replicated.