Cognitive ability in offspring conscripts and cardiovascular disease risk in extended family members: assessing the impact of modifiable risk factors on familial risk.

Background: Previous studies have demonstrated an inverse association between cognitive ability (CA) and risk of cardiovascular diseases (CVDs). This study aims to investigate the associations between CA in offspring and CVD mortality in relatives of the parental generation (ie, parents, aunts/uncles (A/U) and the partners of A/U) and assesses the role of modifiable risk factors on these associations.

Methods: This longitudinal study included nearly 3 million adults who were followed up from age 45 until death.

Individual heterogeneity, educational attainment and cardiovascular mortality: a pooled analysis of Norwegian health surveys.

Background: Smoking, physical inactivity, cholesterol level and systolic blood pressure are well-established risk factors for cardiovascular diseases (CVD). However, even among individuals with similar levels of these factors, a substantial degree of variation in risk may still remain. We investigated the variation in this unexplained risk across educational levels.

Telomere length in relation to fecundability and use of assisted reproductive technologies: the Norwegian Mother, Father, and Child Cohort Study.

Background: Telomere length (TL) has been reported to be associated with conditions such as endometriosis and polycystic ovary syndrome, with some studies finding associations with shorter TL and others with longer TL. In men, studies mostly report associations between shorter TL and sperm quality. To our knowledge, no studies have thus far investigated associations between TL and fecundability or the use of assisted reproductive technologies (ART).

Educational attainment and mental health conditions: a within-sibship Mendelian randomization study.

Importance: Observational studies have demonstrated consistent protective effects of higher educational attainment (EA) on the risk of suffering mental health conditions (MHC). Determining whether these beneficial effects are causal is challenging given the potential role of dynastic effects and demographic factors (assortative mating and population structure) in this association.

Objective: To evaluate to what extent the relationship between EA and various MHC is independent from dynastic effects and demographic factors.

Cardiovascular disease risk factors and infertility: multivariable analyses and one-sample Mendelian randomization analyses in the Trøndelag Health Study.

Study Question: Are cardiovascular disease (CVD) risk factors causally associated with higher risk of infertility among women and men?

Summary Answer: We found evidence to support a causal relationship between smoking initiation and history of infertility in women.

What Is Known Already: Several CVD risk factors are associated with history of infertility. Previous studies using Mendelian randomization (MR) further support a causal relationship between BMI and infertility in women.

Telomere length in relation to fecundability and use of assisted reproductive technologies: the Norwegian Mother, Father, and Child Cohort Study.

In women, shorter telomeres have been reported to be associated with conditions such as endometriosis and polycystic ovary syndrome, whereas other studies have reported the opposite. In men, studies mostly report associations between shorter telomeres and sperm quality. To our knowledge, no studies have thus far investigated the associations between TL and fecundability or the use of ART.

Parental genetically predicted liability for coronary heart disease and risk of adverse pregnancy outcomes: a cohort study.

Background: Adverse pregnancy outcomes (APO) may unmask or exacerbate a woman's underlying risk for coronary heart disease (CHD). We estimated associations of maternal and paternal genetically predicted liability for CHD with lifelong risk of APOs. We hypothesized that associations would be found for women, but not their male partners (negative controls).

Conduct disorder - a comprehensive exploration of comorbidity patterns, genetic and environmental risk factors.

Conduct disorder (CD), a common mental disorder in children and adolescents, is characterized by antisocial behavior. Despite similarities with antisocial personality disorder (ASPD) and possible diagnostic continuity, CD has been shown to precede a range of adult-onset mental disorders. Additionally, little is known about the putative shared genetic liability between CD and adult-onset mental disorders and the underlying gene-environment interplay.

Geographical variation in cardiovascular disease mortality in Norway: The role of life course socioeconomic position and parental health.

Despite substantial geographical variation in cardiovascular (CVD) mortality within countries, little is known about whether this variation can be explained by individuals' life course socioeconomic position (SEP) or differences in family history of premature CVD deaths. Cox proportional hazards models were used to investigate the association between the county of residence at ages 50-59 and CVD death in Norwegians born between 1940 and 1959 and survived to at least age 60, using national data. Individual life course SEP and family history of premature CVD death reduced the geographical variation in CVD mortality across Norwegian counties, but some significant differences remained.

Common genetic and environmental risk for personality disorders and psychotic-like experiences in young adult twins.

Introduction: Psychotic-like experiences (PLE) have been associated with the subsequent emergence of psychotic disorders as well as several other domains of psychopathology. In this twin study, we estimated the genetic and environmental correlations between PLE and 10 personality disorders (PD).

Methods: Diagnoses of 10 PDs according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) and PLE from the Composite International Diagnostic Interview (CIDI) were retrieved for 2793 young adult twins from the Norwegian Twin Registry.

Educational attainment, health outcomes and mortality: a within-sibship Mendelian randomization study.

Background: Previous Mendelian randomization (MR) studies using population samples (population MR) have provided evidence for beneficial effects of educational attainment on health outcomes in adulthood. However, estimates from these studies may have been susceptible to bias from population stratification, assortative mating and indirect genetic effects due to unadjusted parental genotypes. MR using genetic association estimates derived from within-sibship models (within-sibship MR) can avoid these potential biases because genetic differences between siblings are due to random segregation at meiosis.

Governing by commissioning services - Implementing alcohol screening and brief interventions in hospital settings in Norway.

Norwegian health services have undergone marked logistical changes in organization and funding over recent decades. One significant change was the new public management-inspired commissioner's document, first issued in 2013 by the Norwegian Ministry of Health and Care Services, to establish medical and surgical departments' identification of patients with underlying substance abuse problems (Ministry of Health and Care Services, 2013). Herein, we investigate how multiple stakeholders and actors, who bear responsibility in regional and local health trusts, have responded to the commissioned services to establish routines for identifying alcohol and substance abuse problems among patients admitted to medical and surgical wards.

Nucleated red blood cells explain most of the association between DNA methylation and gestational age.

Determining if specific cell type(s) are responsible for an association between DNA methylation (DNAm) and a given phenotype is important for understanding the biological mechanisms underlying the association. Our EWAS of gestational age (GA) in 953 newborns from the Norwegian MoBa study identified 13,660 CpGs significantly associated with GA (p<0.05) after adjustment for cell type composition.

Risk of cardiovascular disease in women and men with subfertility: the Trøndelag Health Study.

Objective: To investigate the association between subfertility and risk of cardiovascular disease (CVD) outcomes.

Design: Prospective study.

Setting: Population-based cohort.

Within-sibship genome-wide association analyses decrease bias in estimates of direct genetic effects.

Estimates from genome-wide association studies (GWAS) of unrelated individuals capture effects of inherited variation (direct effects), demography (population stratification, assortative mating) and relatives (indirect genetic effects). Family-based GWAS designs can control for demographic and indirect genetic effects, but large-scale family datasets have been lacking. We combined data from 178,086 siblings from 19 cohorts to generate population (between-family) and within-sibship (within-family) GWAS estimates for 25 phenotypes.

Preconception leisure-time physical activity and family history of stroke and myocardial infarction associate with preterm delivery: findings from a Norwegian cohort.

Background: Preterm birth poses short and long-term health consequences for mothers and offspring including cardiovascular disease sequelae. However, studies evaluating preexisting family history of cardiovascular disease and risk factors, such as physical activity, as they relate prospectively to risk of delivering preterm are lacking.

Objectives: To evaluate whether preconception past-year weekly leisure-time physical activity or a family history of stroke or of myocardical infarction prior to age 60 years in first degree relatives associated, prospectively, with preterm delivery.

Alcohol consumption and lower risk of cardiovascular and all-cause mortality: the impact of accounting for familial factors in twins.

Background: A moderate to high alcohol consumption is associated with a lower risk of cardiovascular disease (CVD) mortality in comparison with low consumption. The mechanisms underlying this association are not clear and have been suggested to be caused by residual confounding. The main objective of this study was to separate the familial and individual risk for CVD mortality and all-cause mortality related to alcohol consumption.

Educational attainment and mortality in schizophrenia.

Background: Individuals suffering from schizophrenia have a reduced life expectancy with cardiovascular disease (CVD) as a major contributor. Low educational attainment is associated with schizophrenia, as well as with all-cause and CVD mortality. However, it is unknown to what extent low educational attainment can explain the increased mortality in individuals with schizophrenia.

The association between miscarriage and fecundability: the Norwegian Mother, Father and Child Cohort Study.

Study Question: Is fecundability associated with miscarriage history and future miscarriage risk?

Summary Answer: Prior miscarriage was associated with lower fecundability, and participants with a history of subfertility (time-to-pregnancy (TTP) ≥12 months) were at a higher risk of subsequent miscarriage.

What Is Known Already: Although miscarriage and low fecundability share common risk factors, prior studies have reported both lower and higher fecundability after miscarriage.

Study Design, Size, Duration: In this study, we examined two related associations: one, between miscarriage history and subsequent fecundability and, two, between fecundability and miscarriage risk in the subsequent pregnancy.

The role of family factors in the association between early adulthood BMI and risk of cardiovascular disease. An intergenerational study of BMI in early adulthood and cardiovascular mortality in parents, aunts and uncles.

Background: High body mass index (BMI) in childhood and adolescence is related to cardiovascular disease (CVD). Causality is not established because common genetic or early life socioeconomic factors (family factors) may explain this relationship. We aimed to study the role of family factors in the association between BMI and CVD by investigating if early adulthood BMI in conscripts and CVD mortality in their parents/aunts/uncles are related.

Role of a Digital Clinical Decision-Support System in General Practitioners' Management of COPD in Norway.

Background: The study investigated if a web-based clinical decision-support system (CDSS) tool would improve general practitioners' (GPs) accuracy of diagnosis and classification of patients with chronic obstructive pulmonary disease (COPD), and whether nonpharmacological and pharmacological treatment would be better aligned with the COPD guidelines.

Methods: GPs were randomized to either a single use of the CDSS or continuing standard of care. The clinical recommendations of the CDSS were based on the GOLD guidelines and provided suggestions for treatment and management of COPD.

Examining the lower range of the association between alcohol intake and risk of incident hospitalization with atrial fibrillation.

Background: Evidence is sparse on the association between alcohol intakes in the lower range and risk of atrial fibrillation (AF). We aimed to investigate self-reported low and moderate alcohol intakes and subsequent risk of incident AF among current drinkers.

Methods: Norwegian population-based health examination surveys assessing self-reported daily alcohol intake (mean grams per day) were linked to health and population registers.