Twins, full siblings, and half-siblings are increasingly used as comparison groups in matched cohort case-control studies. The "within-pair" estimates acquired through these comparisons free from confounding all factors that shared by the siblings. This has made sibling popular studying associations thought likely to suffer socioeconomic or genetic factors. Despite wide application of designs epidemiology, they have received little scrutiny a statistical methodological standpoint. In this...

Prenatal antidepressant exposure has been associated with adverse outcomes. Previous studies, however, may not have adequately accounted for confounding.To evaluate alternative hypotheses associations between first-trimester and birth neurodevelopmental problems.This retrospective cohort study included Swedish offspring born 1996 2012 followed up through 2013 or censored by death emigration. Analyses controlling pregnancy, maternal paternal covariates, as well sibling comparisons, timing of...

To determine whether women with perinatal depression are at an increased risk of death compared who did not develop the disorder, and full sisters.

Suicidal ideation is common among women with perinatal depression (PND). However, prospective data are limited on the risk, particularly long-term of suicidal behavior (suicide attempt and completed suicide) depression.

A convenient way of dealing with confounding is the sibling comparison design, where outcome in exposed individuals compared their unexposed siblings. The standard analysis designs assumes that exposure and an individual do not affect his/her siblings, sometimes referred to as absence carryover or contagion effects. Unfortunately, there are many situations effects likely be present. In this article, we explore consequences for designs. We show, using causal diagrams, when why lead bias,...

This study examines the familial clustering and relative influence of genetic environmental effects on postterm birth in Swedish population by considering all full- half-siblings born Sweden between 1992 2004. Of eligible 475,429 births, 21% occurred after 41 completed weeks 5.5% 42 gestation. Odds increased if mothers were older, heavier, more educated, primiparous, or carrying a male fetus. The highest odds increase was seen women with previous birth, both same partner (odds ratio = 4.4,...

Maternal polycystic ovary syndrome (PCOS) has been proposed as a model for investigating the role of prenatal androgen exposure in development neuropsychiatric disorders. However, women with PCOS are at higher risk developing psychiatric conditions and previous studies likely confounded by genetic influences.A Swedish nationwide register-based cohort study was conducted to disentangle influence from familial confounding association between maternal offspring attention-deficit/hyperactivity...

To examine associations among interpregnancy interval, the duration from preceding birth to conception of next-born index child, and adverse outcomes using designs that adjust for measured unmeasured factors.In this prospective cohort study, we used population-based Swedish registries 1973 2009 estimate between interval (referent 18-23 months) (ie, preterm [less than 37 weeks gestation], low weight [LBW; less 2,500 g], small gestational age [SGA; greater 2 SDs below average age]). Analyses...

Unmeasured confounding is one of the main sources bias in observational studies. A popular way to reduce use sibling comparisons, which implicitly adjust for several factors early environment or upbringing without requiring them be measured known. In this article we provide a broad exposition statistical analysis methods comparison We further discuss number methodological challenges that arise

Abstract The association between intrauterine growth restriction and cardiovascular disease (CVD) later in life might be confounded by familial factors. We conducted a binational register-based cohort study to assess associations of birth weight for gestational age (GA), proxy restriction, GA with CVD risk early adulthood, before after addressing factors via sibling comparison. included 3,410,334 live nonmalformed singleton births from Sweden (1973–1996) Denmark (1978–1998). During median...

Premenstrual disorders (PMDs) adversely affect the quality of life millions women worldwide, yet research on long-term consequences PMDs is limited, and risk mortality has not been explored.

To determine whether children born to women who use antiseizure medications (ASMs) during pregnancy have higher risk of autism spectrum disorder (ASD) and attention-deficit/hyperactivity (ADHD) independent confounding factors.

Abstract To evaluate associations between maternal anxiety or depression and adverse pregnancy outcomes, taking possible familial confounding interaction with asthma into account, we conducted a cohort study of all singleton births in Sweden 2001–2013. We retrieved information about pregnancy, diagnoses anxiety/depression, asthma, prescribed medication from the Swedish Medical Birth, National Patient, Prescribed Drug Registers. estimated regression models, performed cousin sibling...

Background Premenstrual disorders (PMDs) and perinatal depression (PND) share symptomology the timing of symptoms both conditions coincide with natural hormonal fluctuations, which may indicate a shared etiology. Yet, there is notable absence prospective data on potential bidirectional association between these conditions, crucial for guiding clinical management. Using Swedish nationwide registers prospectively collected data, we aimed to investigate PMDs PND. Methods findings With 1,803,309...

Previous research has been limited in the comprehensive study of associations between use individual antiseizure medications (ASMs) pregnancy and specific groups birth defects, systematic reviews meta-analyses on topic are by pooled samples designs. This investigated defects related to ASM children born women with epilepsy Sweden over 20 years.

Abstract STUDY QUESTION Does endometriosis affect the mental health of women using oral contraceptives? SUMMARY ANSWER Among contraceptive users, with have a higher risk depression compared to those without endometriosis, although absolute increase is small. WHAT IS KNOWN ALREADY Previous studies suggested potential link between and issues, but impact on among users remains unclear. DESIGN, SIZE, DURATION A secondary pooled cohort study utilizing data from two longitudinal patient-centric...

Smaller clinical studies report risks of cardiometabolic dysfunction in brothers women with polycystic ovary syndrome (PCOS). We aim to investigate the risk adverse outcomes men a sister PCOS large longitudinal population-based cohort. Men born Sweden (1973-2013) ≥1 were followed from age 5 until 31 December 2018 (n=1,098,203) and potential diagnosis sisters identified. Risk obesity, type 2 diabetes, or hypertension was estimated using Cox regression. In sub-cohort, association between...

Background Studies in twins may be questioned with respect to their representativeness of the general population, not least considering potential importance fetal environment for future health and disease. To better understand influence twinning have on health, we investigated long-term outcomes twins, singleton siblings singletons from population. Methods Morbidity mortality was contrasted that siblings. These families were then compared population further reveal twin family influences...

To assess the extent to which multiple gestations mediate risk of pregnancy complications from fertility treatment and address possible confounding by underlying infertility.From nearly 1.8 million pregnancies recorded in Swedish Medical Birth Register between 1996 2013, we selected 9.9% (N = 174 067) that occurred couples with known trouble conceiving (clinical infertility). Fertility was identified self-reports, medical records procedural information clinics. We used logistic regression...

Induction of labor is a frequently performed obstetrical intervention. It would thus be great concern if reported associations between induction and offspring risk autism spectrum disorders (ASD) reflected causal influence.To assess the with ASD, comparing differentially exposed relatives (siblings cousins discordant for induction).Follow-up all live births in Sweden 1992 2005, defined Medical Birth Register. The register was linked to population registers familial relations, inpatient...