| 1. |
- Merid, Simon Kebede, et al.
(författare)
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Epigenome-wide meta-analysis of blood DNA methylation in newborns and children identifies numerous loci related to gestational age
- 2020
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Ingår i: Genome Medicine. - Stockholm : Karolinska Institutet, Dept of Clinical Science and Education, Södersjukhuset. - 1756-994X.
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Tidskriftsartikel (refereegranskat)abstract
- Background: Preterm birth and shorter duration of pregnancy are associated with increased morbidity in neonatal and later life. As the epigenome is known to have an important role during fetal development, we investigated associations between gestational age and blood DNA methylation in children. Methods: We performed meta-analysis of Illumina's HumanMethylation450-array associations between gestational age and cord blood DNA methylation in 3648 newborns from 17 cohorts without common pregnancy complications, induced delivery or caesarean section. We also explored associations of gestational age with DNA methylation measured at 4-18 years in additional pediatric cohorts. Follow-up analyses of DNA methylation and gene expression correlations were performed in cord blood. DNA methylation profiles were also explored in tissues relevant for gestational age health effects: fetal brain and lung. Results: We identified 8899 CpGs in cord blood that were associated with gestational age (range 27-42 weeks), at Bonferroni significance, P < 1.06 × 10- 7, of which 3343 were novel. These were annotated to 4966 genes. After restricting findings to at least three significant adjacent CpGs, we identified 1276 CpGs annotated to 325 genes. Results were generally consistent when analyses were restricted to term births. Cord blood findings tended not to persist into childhood and adolescence. Pathway analyses identified enrichment for biological processes critical to embryonic development. Follow-up of identified genes showed correlations between gestational age and DNA methylation levels in fetal brain and lung tissue, as well as correlation with expression levels. Conclusions: We identified numerous CpGs differentially methylated in relation to gestational age at birth that appear to reflect fetal developmental processes across tissues. These findings may contribute to understanding mechanisms linking gestational age to health effects.
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| 2. |
- Class, Quetzal A., et al.
(författare)
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Outcome-dependent associations between short interpregnancy interval and offspring psychological and educational problems : a population-based quasi-experimental study
- 2018
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Ingår i: International Journal of Epidemiology. - Stockholm : Oxford University Press. - 0300-5771 .- 1464-3685. ; 47:4, s. 1159-1168
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Tidskriftsartikel (refereegranskat)abstract
- Background: Causal interpretation of associations between short interpregnancy interval (the duration from the preceeding birth to the conception of the next-born index child) and the offspring's psychological and educational problems may be influenced by a failure to account for unmeasured confounding.Methods: Using population-based Swedish data from 1973-2009, we estimated the association between interpregnancy interval and outcomes [autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), severe mental illness, suicide attempt, criminality, substance-use problem and failing grades] while controlling for measured covariates. We then used cousin comparisons, post-birth intervals (the interval between the second-and third-born siblings to predict second-born outcomes) and sibling comparisons to assess the influence of unmeasured confounding. We included an exploratory analysis of long interpregnancy interval.Results: Interpregnancy intervals of 0-5 and 6-11 months were associated with higher odds of outcomes in cohort analyses. Magnitudes of association were attenuated following adjustment for measured covariates. Associations were eliminated for ADHD, severe mental illness and failing grades, but maintained magnitude for ASD, suicide attempt, criminality and substance-use problem in cousin comparisons. Post-birth interpregnancy interval and sibling comparisons suggested some familial confounding. Associations did not persist across models of long interpregnancy interval.Conclusions: Attenuation of the association in cousin comparisons and comparable post-birth interval associations suggests that familial genetic or environmental confounding accounts for a majority of the association for ADHD, severe mental illness and failing grades. Modest associations appear independently of covariates for ASD, suicide attempt, criminality and substance-use problem. Post-birth analyses and sibling comparisons, however, show some confounding in these associations.
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| 3. |
- D'Onofrio, Brian M., et al.
(författare)
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Translational Epidemiologic Approaches to Understanding the Consequences of Early-Life Exposures
- 2016
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Ingår i: Behavior Genetics. - New York, USA : Springer. - 0001-8244 .- 1573-3297. ; 46:3, s. 315-328
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Forskningsöversikt (refereegranskat)abstract
- Prominent developmental theories posit a causal link between early-life exposures and later functioning. Yet, observed associations with early exposures may not reflect causal effects because of genetic and environmental confounding. The current manuscript describes how a systematic series of epidemiologic analyses that combine several genetically-informative designs and statistical approaches can help distinguish between competing theories. In particular, the manuscript details how combining the use of measured covariates with sibling-comparisons, cousin-comparisons, and additional designs can help elucidate the sources of covariation between early-life exposures and later outcomes, including the roles of (a) factors that are not shared in families, including a potential causal effect of the exposure; (b) carryover effects from the exposure of one child to the next; and (c) familial confounding. We also describe key assumptions and how they can be critically evaluated. Furthermore, we outline how subsequent analyses, including effect decomposition with respect to measured, plausible mediators, and quantitative genetic models can help further specify the underlying processes that account for the associations between early-life exposures and offspring outcomes.
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| 4. |
- Guxens, Monica, et al.
(författare)
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Air pollution exposure during pregnancy and childhood autistic traits in four European population-based cohort studies : the ESCAPE project
- 2016
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Ingår i: Environmental Health Perspectives. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0091-6765 .- 1552-9924.
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prenatal exposure to air pollutants has been suggested as a possible etiologic factor for the occurrence of autism spectrum disorder. Objectives: We aimed to assess whether prenatal air pollution exposure is associated with childhood autistic traits in the general population. Methods: Ours was a collaborative study of four European population-based birth/child cohorts— CATSS (Sweden), Generation R (the Netherlands), GASPII (Italy), and INMA (Spain). Nitrogen oxides (NO2, NOx) and particulate matter (PM) with diameters of ≤ 2.5 μm (PM2.5), ≤ 10 μm (PM10), and between 2.5 and 10 μm (PMcoarse), and PM2.5 absorbance were estimated for birth addresses by land-use regression models based on monitoring campaigns performed between 2008 and 2011. Levels were extrapolated back in time to exact pregnancy periods. We quantitatively assessed autistic traits when the child was between 4 and 10 years of age. Children were classified with autistic traits within the borderline/clinical range and within the clinical range using validated cut-offs. Adjusted cohort-specific effect estimates were combined using random-effects meta-analysis. Results: A total of 8,079 children were included. Prenatal air pollution exposure was not associated with autistic traits within the borderline/clinical range (odds ratio = 0.94; 95% CI: 0.81, 1.10 per each 10‑μg/m3 increase in NO2 pregnancy levels). Similar results were observed in the different cohorts, for the other pollutants, and in assessments of children with autistic traits within the clinical range or children with autistic traits as a quantitative score. Conclusions: Prenatal exposure to NO2 and PM was not associated with autistic traits in children from 4 to 10 years of age in four European population-based birth/child cohort studies.
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| 5. |
- Khashan, Ali S, et al.
(författare)
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Gestational age and birth weight and the risk of childhood type 1 diabetes : a population-based cohort and sibling design study
- 2015
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Ingår i: Diabetes Care. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0149-5992 .- 1935-5548.
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: We investigated the effects of gestational age, birthweight, small for gestational age (SGA) and large for gestational age (LGA) on childhood type 1 diabetes. Methods: We conducted a population-based cohort study of all singleton live births in Sweden between 1973-2009 and a sibling-control study. Perinatal data were extracted from the Swedish Medical Birth Register. Children with type 1 diabetes diagnosis were identified from the Swedish National Patient Register. Log-linear Poisson regression and conditional logistic regression were used for data analysis. Results: The study cohort consisted of 3,624,675 singleton live births (42,411,054 person-years). There were 13,944 type 1 diabetes cases during the study period. The sibling-control study consisted of 11,403 children with type 1 diabetes and 17,920 siblings. Gestational age between 33-36 weeks (RR=1.18; [95%CIs: 1.09, 1.28) and 37-38 weeks (RR=1.12; [95%CIs: 1.07, 1.17]) was associated with type 1 diabetes in the cohort study and remained significant in the sibling-control study. SGA (RR=0.83; [95%CIs: 0.75, 0.93]) and LGA (RR=1.14; [95%CIs: 1.04, 1.24]) were associated with type 1 diabetes in the cohort study. The SGA association remained unchanged in the sibling study while the LGA association disappeared. Very low birthweight was associated with a reduced risk of type 1 diabetes. Conclusions: The findings suggest a small association between gestational age and type 1 diabetes that is not likely due to familial confounding factors. Gestational age and type 1 diabetes may be related to insulin resistance due to early life growth restriction or altered gut microbiota in preterm babies.
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| 6. |
- Khashan, Ali S, et al.
(författare)
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Mode of obstetrical delivery and type 1 diabetes : a sibling design study
- 2014
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Ingår i: Pediatrics. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0031-4005 .- 1098-4275.
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: We investigated the association between cesarean section (CS) and type 1 diabetes (T1D), and if the association remains after accounting for familial confounding by using a sibling-control design. METHODS: We conducted a population-based cohort study of all singleton live births in Sweden between 1982 and 2009, followed by sibling-control analyses. T1D diagnoses were identified from the Swedish National Patient Register. Mode of delivery was categorized into unassisted vaginal delivery (reference group), instrumental vaginal delivery (IVD), emergency CS, and elective CS. The statistical analysis was conducted in 2 steps: firstly log-linear Poisson regression with aggregated person-years by using the full cohort; secondly, conditional logistic regression for sibling-control analyses. The sibling analysis included siblings who were discordant for both mode of delivery and T1D. RESULTS: In the cohort analyses (N = 2 638 083), there was an increased risk of childhood T1D among children born by elective CS (adjusted relative risk [RR] = 1.15 [95% confidence interval: 1.06-1.25]) and IVD (RR=1.14 [1.06-1.23]) but not emergency CS (RR = 1.02 [0.95-1.11]) when compared with children born by unassisted vaginal birth. However, the effect of elective CS and IVD on childhood T1D almost disappeared and became nonsignificant in the sibling-control analyses. CONCLUSIONS: The present findings suggest a small association between elective CS and IVD and T1D. The sibling-control results, however, suggest that these findings are not consistent with causal effects of mode of delivery on T1D and may be due to familial confounders such as genetic susceptibility and environmental factors.
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| 7. |
- Medsker, Brock H, et al.
(författare)
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Maternal depressive symptoms, maternal asthma, and asthma in school-aged children
- 2017
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Ingår i: Annals of Allergy, Asthma & Immunology. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1081-1206. ; 118:1, s. 55-U146
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Little is known about the joint effects of maternal asthma and maternal depression on childhood asthma. OBJECTIVE: To examine whether maternal depression and maternal asthma lead to greater risk of childhood asthma than maternal asthma alone. METHODS: Cross-sectional studies of children (6-14 years old) in San Juan, Puerto Rico (n = 655) and Sweden (n = 6,887) were conducted. In Puerto Rico, maternal depressive symptoms were defined using the Center for Epidemiologic Studies Depression Scale (CES-D) questionnaire. In Sweden, maternal physician-diagnosed depression was derived from national registries, and maternal depressive symptoms were defined using an abbreviated CES-D questionnaire. Childhood asthma was defined as physician-diagnosed asthma plus current wheeze (in Puerto Rico) or plus medication use (in Sweden). Logistic regression was used for multivariable analysis. RESULTS: Compared with Puerto Rican children whose mothers had neither asthma nor depressive symptoms, those whose mothers had asthma but no depressive symptoms had 3.2 times increased odds of asthma (95% confidence interval [CI] = 2.1-4.8) and those whose mothers had asthma and depressive symptoms had 6.5 times increased odds of asthma (95% CI = 3.3-13.0). Similar results were obtained for maternal depression and maternal asthma in the Swedish cohort (odds ratio for maternal asthma without maternal depression = 2.8, 95% CI = 2.1-3.7; odds ratio for maternal asthma and maternal depression = 4.0, 95% CI = 1.7-9.6). Although the estimated effect of maternal asthma on childhood asthma was increased when maternal depressive symptoms (Puerto Rico) or maternal depression (Sweden) was present, there were no statistically significant additive interactions. CONCLUSION: Maternal depression can further increase the risk of asthma in children whose mothers have a history of asthma.
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| 8. |
- Mustelin, L., et al.
(författare)
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Risk of eating disorders in immigrant populations
- 2017
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Ingår i: Acta Psychiatrica Scandinavica. - Stockholm : Wiley. - 0001-690X .- 1600-0447. ; 136:2, s. 156-165
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The risk of certain psychiatric disorders is elevated among immigrants. To date, no population studies on immigrant health have addressed eating disorders. We examined whether risk of eating disorders in first- and second-generation immigrants differs from native-born Danes and Swedes. Method: All individuals born 1984–2002 (Danish cohort) and 1989–1999 (Swedish cohort) and residing in the respective country on their 10th birthday were included. They were followed up for the development of eating disorders based on out-patient and in-patient data. Results: The risks of all eating disorder types were lower among first-generation immigrants compared to the native populations: Incidence-rate ratio (95% confidence interval) was 0.39 (0.29, 0.51) for anorexia nervosa, 0.60 (0.42, 0.83) for bulimia nervosa, and 0.62 (0.47, 0.79) for other eating disorders in Denmark and 0.27 (0.21, 0.34) for anorexia nervosa, 0.30 (0.18, 0.51) for bulimia nervosa, and 0.39 (0.32, 0.47) for other eating disorders in Sweden. Likewise, second-generation immigrants by both parents were at lower risk, whereas those with only one foreign-born parent were not. Conclusion: The decreased risk of eating disorders among immigrants is opposite to what has been observed for other psychiatric disorders, particularly schizophrenia. Possible explanations include buffering sociocultural factors and underdetection in health care.
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| 9. |
- Sujan, Ayesha C., et al.
(författare)
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A Genetically Informed Study of the Associations Between Maternal Age at Childbearing and Adverse Perinatal Outcomes
- 2016
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Ingår i: Behavior Genetics. - New York, USA : Springer. - 0001-8244 .- 1573-3297. ; 46:3, s. 431-456
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Tidskriftsartikel (refereegranskat)abstract
- We examined associations of maternal age at childbearing (MAC) with gestational age and fetal growth (i.e., birth weight adjusting for gestational age), using two genetically informed designs (cousin and sibling comparisons) and data from two cohorts, a population-based Swedish sample and a nationally representative United States sample. We also conducted sensitivity analyses to test limitations of the designs. The findings were consistent across samples and suggested that, associations observed in the population between younger MAC and shorter gestational age were confounded by shared familial factors; however, associations of advanced MAC with shorter gestational age remained robust after accounting for shared familial factors. In contrast to the gestational age findings, neither early nor advanced MAC was associated with lower fetal growth after accounting for shared familial factors. Given certain assumptions, these findings provide support for a causal association between advanced MAC and shorter gestational age. The results also suggest that there are not causal associations between early MAC and shorter gestational age, between early MAC and lower fetal growth, and between advanced MAC and lower fetal growth.
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| 10. |
- Sujan, Ayesha C., et al.
(författare)
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A population-based study of concurrent prescriptions of opioid analgesic and selective serotonin reuptake inhibitor medications during pregnancy and risk for adverse birth outcomes
- 2021
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Ingår i: Paediatric and Perinatal Epidemiology. - : Blackwell Science Ltd.. - 0269-5022 .- 1365-3016. ; 35:2, s. 184-193
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Pregnant women with painful conditions often have mental health problems, including depression and anxiety. Co-morbid conditions may cause pregnant women to use multiple medications, although safety of such practice is poorly understood.OBJECTIVES: We investigated the influence of combined prescriptions of opioid analgesics and selective serotonin reuptake inhibitors (SSRIs) during pregnancy on two adverse birth outcomes.METHODS: We analysed Swedish population-based births (n = 688 914) between 2007 and 2013. Using national registers, we obtained data on filled medication prescriptions, birth outcomes, and a wide range of parental characteristics. We estimated preterm birth and small-for-gestational-age risk following independent or combined prescriptions of the two medications compared with no filled prescriptions for either medication. We adjusted for confounders using inverse probability of treatment weights.RESULTS: After adjusting for confounders, preterm birth risk was higher among women with opioid analgesic prescriptions only (5.9%; risk ratio [RR] 1.27, 95% confidence interval [CI] 1.22, 1.33), SSRIs only (6.2%; RR 1.34, 95% CI 1.27, 1.42), and both medications (7.8%; RR 1.70, 95% CI 1.47, 1.96) compared with unexposed women (4.6%). The interaction between the medications on preterm birth was small (risk difference [RD] 0.4%, 95% CI -0.8%, 1.6%); relative excess risk due to interaction [RERI] 0.09, 95% CI -0.17, 0.34; RR 1.00, 95% CI 0.85, 1.17). For small for gestational age, risk was approximately 2% across all groups, and there was no interaction between the medications (RD 0.3%, 95% CI -0.4%, 1.1%); RERI 0.15, 95% CI -0.16, 0.47; RR 1.15, 95% CI 0.87, 1.52).CONCLUSIONS: Compared with unexposed pregnancies, those with either medication alone had a small increased risk for preterm birth but no increased risk for small for gestational age. The magnitude of associations with combined exposure to both medications were not greater than the sum of the associations with each medication considered individually.
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