Maternal vitamin B12 during pregnancy and schizophrenia in offspring.

Background: Maternal nutritional deficiency is linked with several adverse outcomes in offspring but the link between maternal vitamin B12 levels and offspring schizophrenia remains unexplored.

Methods: In this nationwide population-based nested case-control design, 1145 schizophrenia cases were born between 1987-1997 and diagnosed by 2017 and each case were matched with a control. Maternal vitamin B12 levels during the first and early second trimesters of pregnancy were measured using chemiluminescence microparticle immunoassay from maternal sera.

Maternal vitamin D levels during pregnancy and offspring schizophrenia.

Background: Findings from previous studies on maternal 25(OH)D levels during pregnancy and offspring schizophrenia are limited and inconsistent.

Methods: We used nationwide population-based register data with a nested case-control design to examine the association between maternal 25(OH)D levels during pregnancy and offspring schizophrenia. The cases of schizophrenia (n = 1145) were born from 1987 to 1997, and received a diagnosis of schizophrenia by 2017, and were matched with equal number of controls.

EFFICIENT ESTIMATION OF THE MAXIMAL ASSOCIATION BETWEEN MULTIPLE PREDICTORS AND A SURVIVAL OUTCOME.

This paper develops a new approach to post-selection inference for screening high-dimensional predictors of survival outcomes. Post-selection inference for right-censored outcome data has been investigated in the literature, but much remains to be done to make the methods both reliable and computationally-scalable in high-dimensions. Machine learning tools are commonly used to provide of survival outcomes, but the estimated effect of a selected predictor suffers from confirmation bias unless the selection is taken into account.

Prenatal organochlorine pollutant exposure and risk of schizophrenia in a national birth cohort.

Non-genetic prenatal exposures have been associated with schizophrenia risk. However, the role of prenatal exposure to environmental neurotoxicants in offspring schizophrenia risk has been studied in only limited instances. Polychlorinated biphenyls (PCBs) and the pesticide metabolite p,p'-dichlorodiphenyl dichloroethylene (DDE) have been linked to neurodevelopmental outcomes, including impairments implicated in schizophrenia.

Maternal Serum Vitamin B12 during Pregnancy and Offspring Autism Spectrum Disorder.

This study examined the association between maternal serum vitamin B12 levels during early pregnancy and offspring autism spectrum disorders (ASD) and subtypes. Based on a Finnish national birth cohort, case offspring = 1558) born in 1987-2007 and diagnosed with ASD by 2015 were matched with one control on date of birth, sex and place of birth. Maternal vitamin B12 levels were measured during first and early second trimesters of pregnancy.

Significance testing for canonical correlation analysis in high dimensions.

We consider the problem of testing for the presence of linear relationships between large sets of random variables based on a post-selection inference approach to canonical correlation analysis. The challenge is to adjust for the selection of subsets of variables having linear combinations with maximal sample correlation. To this end, we construct a stabilized one-step estimator of the euclidean-norm of the canonical correlations maximized over subsets of variables of pre-specified cardinality.

Fitting additive risk models using auxiliary information.

There has been a growing interest in incorporating auxiliary summary information from external studies into the analysis of internal individual-level data. In this paper, we propose an adaptive estimation procedure for an additive risk model to integrate auxiliary subgroup survival information via a penalized method of moments technique. Our approach can accommodate information from heterogeneous data.

Maternal serum persistent organic pollutant exposure and offspring diagnosed ADHD in a national birth cohort.

Background: Evidence implicates environmental factors in attention-deficit/hyperactivity disorder (ADHD) risk. Prenatal exposures to polychlorinated biphenyls (PCBs) and the pesticide metabolite p,p'-dichlorodiphenyl dichloroethylene (DDE) have been linked to lower cognitive ability, increased impulsivity, and attention related deficits in the offspring. However, information on the relationship of these exposures to the risk of clinically diagnosed ADHD is limited.

Maternal Vitamin D Levels During Pregnancy and Offspring Autism Spectrum Disorder.

Background: Findings from previous studies on maternal 25-hydroxyvitamin D [25(OH)D] levels during pregnancy and autism spectrum disorder (ASD) in offspring are inconsistent.

Methods: The association between maternal 25(OH)D levels during pregnancy and offspring ASD was examined using data from a nationwide population-based register with a nested case-control study design. The ASD cases (n = 1558) were born between 1987 and 2004 and received a diagnosis of ASD by 2015; cases were matched with an equal number of controls.

A biomarker-based study of prenatal smoking exposure and autism in a Finnish national birth cohort.

Maternal exposure to tobacco smoke during pregnancy is a common and persistent exposure linked to adverse neurodevelopmental outcomes in the offspring. However, previous studies provide mixed evidence regarding the relationship between prenatal smoking and offspring autism. This study used cotinine level, a biomarker for nicotine, to investigate the relationship between prenatal smoking and autism.

Maternal serum Vitamin B12 and offspring attention-deficit/hyperactivity disorder (ADHD).

Maternal Vitamin B12 deficiency during pregnancy is associated with offspring neuropsychiatric disorders. Few previous studies examining this association with attention-deficit/hyperactivity disorder (ADHD) report inconsistent findings. The study examines the association between maternal serum Vitamin B12 levels and offsprings' risk of ADHD.

Robust data-driven identification of risk factors and their interactions: A simulation and a study of parental and demographic risk factors for schizophrenia.

Objectives: Few interactions between risk factors for schizophrenia have been replicated, but fitting all such interactions is difficult due to high-dimensionality. Our aims are to examine significant main and interaction effects for schizophrenia and the performance of our approach using simulated data.

Methods: We apply the machine learning technique elastic net to a high-dimensional logistic regression model to produce a sparse set of predictors, and then assess the significance of odds ratios (OR) with Bonferroni-corrected p-values and confidence intervals (CI).

Increased Risk of ADHD at Short and Long Interpregnancy Intervals in a National Birth Cohort.

Background: Short or long interpregnancy interval (IPI) may adversely impact conditions for foetal development. Whether attention deficit hyperactivity disorder (ADHD) is related to IPI has been largely unexplored.

Objectives: To examine the association between IPI and ADHD in a large, population-based Finnish study.

Marginal screening for high-dimensional predictors of survival outcomes.

This study develops a marginal screening test to detect the presence of significant predictors for a right-censored time-to-event outcome under a high-dimensional accelerated failure time (AFT) model. Establishing a rigorous screening test in this setting is challenging, because of the right censoring and the post-selection inference. In the latter case, an implicit variable selection step needs to be included to avoid inflating the Type-I error.

Hybrid combinations of parametric and empirical likelihoods.

This paper develops a hybrid likelihood (HL) method based on a compromise between parametric and nonparametric likelihoods. Consider the setting of a parametric model for the distribution of an observation with parameter . Suppose there is also an estimating function (·, ) identifying another parameter via E(, ) = 0, at the outset defined independently of the parametric model.

NONPARAMETRIC TESTING FOR MULTIPLE SURVIVAL FUNCTIONS WITH NON-INFERIORITY MARGINS.

New nonparametric tests for the ordering of multiple survival functions are developed with the possibility of right censorship taken into account. The motivation comes from non-inferiority trials with multiple treatments. The proposed tests are based on nonparametric likelihood ratio statistics, which are known to provide more powerful tests than Wald-type procedures, but in this setting have only been studied for pairs of survival functions or in the absence of censoring.

Stein's method and approximating the quantum harmonic oscillator.

Hall et al. (2014) recently proposed that quantum theory can be understood as the continuum limit of a deterministic theory in which there is a large, but finite, number of classical "worlds." A resulting Gaussian limit theorem for particle positions in the ground state, agreeing with quantum theory, was conjectured in Hall et al.

Proband and Familial Autoimmune Diseases Are Associated With Proband Diagnosis of Autism Spectrum Disorders.

Objective: There is evidence that parental autoimmune diseases (ADs) are associated with autism spectrum disorders (ASD) in offspring. The association between offspring ASD and ADs diagnosed in siblings and probands remains less clear. We examined whether proband and familial diagnoses of ADs were associated with increased odds of ASD in probands.

Association of Maternal Insecticide Levels With Autism in Offspring From a National Birth Cohort.

Objective: Autism is a complex neurodevelopmental disorder with a largely unknown etiology. To date, few studies have investigated prenatal exposure to toxins and risk of autism by using maternal biomarkers of exposure. Persistent organic pollutants are lipophilic halogenated organic compounds and include the insecticide dichlorodiphenyltrichloroethane (DDT), as well as its metabolite p,p'-dichlorodiphenyl dichloroethylene (p,p'-DDE), and polychlorinated biphenyls (PCBs).

Marginal screening of 2 × 2 tables in large-scale case-control studies.

Assessing the statistical significance of risk factors when screening large numbers of tables that cross-classify disease status with each type of exposure poses a challenging multiple testing problem. The problem is especially acute in large-scale genomic case-control studies. We develop a potentially more powerful and computationally efficient approach (compared with existing methods, including Bonferroni and permutation testing) by taking into account the presence of complex dependencies between the tables.

Testing for Marginal Linear Effects in Quantile Regression.

This paper develops a new marginal testing procedure to detect the presence of significant predictors associated with the conditional quantiles of a scalar response. The idea is to fit the marginal quantile regression on each predictor one at a time, and then base the test on the -statistics associated with the most predictive predictors. A resampling method is devised to calibrate this test statistic, which has non-regular limiting behavior due to the selection of the most predictive variables.

Computer-Assisted Motivational Interviewing Intervention to Facilitate Teen Pregnancy Prevention and Fitness Behavior Changes: A Randomized Trial for Young Men.

Purpose: Despite recent declines, teen unintended pregnancy and sexually transmitted infections in the United States remain at levels higher than comparable nations. Initiatives to prevent teen pregnancy have focused primarily on female adolescents; how to effectively engage young men to reduce their risk of fathering a teen pregnancy has not been well studied. We proposed to adapt an innovative computer-assisted motivational interviewing (CAMI) intervention, originally designed and tested with young women, for use with young men, aged 15-24 years, to reduce their risk of fathering a teen pregnancy.

Convergence of empirical distributions in an interpretation of quantum mechanics.

From its beginning, there have been attempts by physicists to formulate quantum mechanics without requiring the use of wave functions. An interesting recent approach takes the point of view that quantum effects arise solely from the interaction of finitely many classical "worlds." The wave function is then recovered (as a secondary object) from observations of particles in these worlds, without knowing the world from which any particular observation originates.

Altered growth trajectory of head circumference during infancy and schizophrenia in a National Birth Cohort.

Identification of abnormalities in the developmental trajectory during infancy of future schizophrenia cases offers the potential to reveal pathogenic mechanisms of this disorder. Previous studies of head circumference in pre-schizophrenia were limited to measures at birth. The use of growth acceleration of head circumference (defined as the rate of change in head circumference) provides a more informative representation of the maturational landscape of this measure compared to studies based on static head circumference measures.