| 1. |
- Butwicka, Agnieszka, et al.
(author)
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Increased Risk for Substance Use-Related Problems in Autism Spectrum Disorders : A Population-Based Cohort Study
- 2017
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In: Journal of autism and developmental disorders. - New York, USA : Springer. - 0162-3257 .- 1573-3432. ; 47:1, s. 80-89
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Journal article (peer-reviewed)abstract
- Despite limited and ambiguous empirical data, substance use-related problems have been assumed to be rare among patients with autism spectrum disorders (ASD). Using Swedish population-based registers we identified 26,986 individuals diagnosed with ASD during 1973-2009, and their 96,557 non-ASD relatives. ASD, without diagnosed comorbidity of attention deficit hyperactivity disorder (ADHD) or intellectual disability, was related to a doubled risk of substance use-related problems. The risk of substance use-related problems was the highest among individuals with ASD and ADHD. Further, risks of substance use-related problems were increased among full siblings of ASD probands, half-siblings and parents. We conclude that ASD is a risk factor for substance use-related problems. The elevated risks among relatives of probands with ASD suggest shared familial (genetic and/or shared environmental) liability.
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| 2. |
- Chen, Qi, et al.
(author)
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Shared familial risk factors between attention-deficit/hyperactivity disorder and overweight/obesity : a population-based familial coaggregation study in Sweden
- 2017
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In: Journal of Child Psychology and Psychiatry. - Stockholm : Wiley-Blackwell Publishing Inc.. - 0021-9630 .- 1469-7610. ; 58:6, s. 711-718
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Journal article (peer-reviewed)abstract
- Background: Despite meta-analytic evidence for the association between attention-deficit/hyperactivity disorder (ADHD) and overweight/obesity, the mechanisms underlying the association are yet to be fully understood.Methods By linking multiple Swedish national and regional registers, we identified 472,735 index males born during 1973-1992, with information on body weight and height directly measured before they were conscripted for military service. We further identified 523,237 full siblings born during 1973-2002 for the index males. All individuals were followed up from their third birthday to December 31, 2009 for ADHD diagnosis. Logistic regression models were used to estimate the association between overweight/obesity in index males and ADHD in their full siblings.Results: Siblings of index males with overweight/obesity had increased risk for ADHD (overweight: OR = 1.14, 95% CI = 1.05-1.24; obesity: OR = 1.42, 95% CI = 1.24-1.63), compared with siblings of index males with normal weight. The results were adjusted for birth year of the index male and sex of the sibling. After further adjustment for ADHD status of the index male, the familial coaggregation remained significant (overweight: OR = 1.13, 95% CI = 1.04-1.22; obesity: OR = 1.38, 95% CI = 1.21-1.57). The results were similar across sex of the siblings.Conclusions: Attention-deficit/hyperactivity disorder and overweight/obesity share familial risk factors, which are not limited to those causing overweight/obesity through the mediation of ADHD. Future research aiming at identifying family-wide environmental risk factors as well as common pleiotropic genetic variants contributing to both traits is warranted.
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| 3. |
- Coelho, Vera, et al.
(author)
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Preschool practices in Sweden, Portugal, and the United States
- 2021
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In: Early Childhood Research Quarterly. - : Elsevier BV. - 0885-2006 .- 1873-7706. ; 55, s. 79-96
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Journal article (peer-reviewed)abstract
- Across countries, there are important differences related to the goals, organization, and educational philosophies of care provided to young children prior to formal schooling. Those differences are likely reflected in the classroom practices and teacher-child interactions within a country's early childhood education and care (ECEC) classrooms. This study aims to evaluate the within-country relevance of two classroom observation measures primarily based on a behavioral count approach focused on teacher and child behaviors; and to examine preschool practices in Sweden, Portugal, and the U.S., as they reflect each country's ECEC goals, organization, and educational philosophies. Participants are 78 preschool settings in Sweden, 42 in Portugal, and 168 in the U.S. Results show that the measures targeted culturally-relevant behaviors and provided inter-rater reliability for the behavior count variables in the three countries. Future collaborations may address additional culturally-specific variables. The behavioral descriptions yielded by combining behavioral counts of the measures are analyzed by researchers from the relevant country for insights to the country's values related to early childhood as well as current debates regarding care for children. Measures that provide comprehensive descriptions of classroom settings and apply minimal external or comparative value judgments on the behaviors observed are of practical utility for collaborative international work.
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| 4. |
- D'Onofrio, Brian M., et al.
(author)
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Translational Epidemiologic Approaches to Understanding the Consequences of Early-Life Exposures
- 2016
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In: Behavior Genetics. - New York, USA : Springer. - 0001-8244 .- 1573-3297. ; 46:3, s. 315-328
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Research review (peer-reviewed)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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| 5. |
- Gong, Tong, et al.
(author)
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Parental socioeconomic status, childhood asthma and medication use : a population-based study
- 2014
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In: PLoS One. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1932-6203.
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Journal article (peer-reviewed)abstract
- BACKGROUND: Little is known about how parental socioeconomic status affects offspring asthma risk in the general population, or its relation to healthcare and medication use among diagnosed children. METHODS: This register-based cohort study included 211,520 children born between April 2006 and December 2008 followed until December 2010. Asthma diagnoses were retrieved from the National Patient Register, and dispensed asthma medications from the Prescribed Drug Register. Parental socioeconomic status (income and education) were retrieved from Statistics Sweden. The associations between parental socioeconomic status and outcomes were estimated by Cox proportional hazard regression. RESULTS: Compared to the highest parental income level, children exposed to all other levels had increased risk of asthma during their first year of life (e.g. hazard ratio, HR 1.19, 95% confidence interval, CI 1.09-1.31 for diagnosis and HR 1.17, 95% CI 1.08-1.26 for medications for the lowest quintile) and the risk was decreased after the first year, especially among children from the lowest parental income quintile (HR 0.84, 95% CI 0.77-0.92 for diagnosis, and HR 0.80, 95% CI 0.74-0.86 for medications). Further, compared to children with college-educated parents, those whose parents had lower education had increased risk of childhood asthma regardless of age. Children with the lowest parental education had increased risk of an inpatient (HR 2.07, 95% CI 1.61-2.65) and outpatient (HR 1.32, 95% CI 1.18-1.47) asthma diagnosis. Among diagnosed children, those from families with lower education used fewer controller medications than those whose parents were college graduates. CONCLUSIONS: Our findings indicate an age-varying association between parental income and childhood asthma and consistent inverse association regardless of age between parental education and asthma incidence, dispensed controller medications and inpatient care which should be further investigated and remedied.
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| 6. |
- Pettersson, Erik, et al.
(author)
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Birth weight as an independent predictor of ADHD symptoms : a within-twin pair analysis
- 2015
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In: Journal of Child Psychology and Psychiatry. - Hoboken, USA : Wiley-Blackwell. - 0021-9630 .- 1469-7610. ; 56:4, s. 453-459
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Journal article (peer-reviewed)abstract
- Background Studies have found an association between low birth weight and ADHD, but the nature of this relation is unclear. First, it is uncertain whether birth weight is associated with both of the ADHD dimensions, inattentiveness and hyperactivity-impulsivity. Second, it remains uncertain whether the association between birth weight and ADHD symptom severity is confounded by familial factors.Method: Parents of all Swedish 9- and 12-year-old twins born between 1992 and 2000 were interviewed for DSM-IV inattentive and hyperactive-impulsive ADHD symptoms by the Autism - Tics, AD/HD and other Comorbidities (A-TAC) inventory (N = 21,775 twins). Birth weight was collected prospectively through the Medical Birth Registry. We used a within-twin pair design to control for genetic and shared environmental factors.Results: Reduced birth weight was significantly associated with a mean increase in total ADHD (β = -.42; 95% CI: -.53, -.30), inattentive (β = -.26; 95% CI: -.33, -.19), and hyperactive-impulsive (β = -.16; 95% CI: -.22, -.10) symptom severity. These results imply that a change of one kilogram of birth weight corresponded to parents rating their child nearly one unit higher (going from "no" to "yes, to some extent" on a given symptom) on the total ADHD scale. These associations remained within pairs of MZ and DZ twins, and were also present when restricting the analyses to full term births.Conclusions: There is an independent association between low birth weight and all forms of ADHD symptoms, even after controlling for all environmental and genetic confounds shared within twin pairs. These results indicate that fetal growth restriction (as reflected in birth weight differences within twin pairs) and/or the environmental factors which influence it is in the casual pathway leading to ADHD.
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| 7. |
- Song, Huan, et al.
(author)
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The familial co-aggregation of stress-related disorders and autoimmune diseases
- 2019
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In: Behavior Genetics. - : Springer. - 0001-8244 .- 1573-3297. ; 49:6, s. 539-540
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Journal article (other academic/artistic)abstract
- Background: Evidence has emerged indicating a role of stress-related disorders in the development of autoimmune diseases. However, it remains unknown whether genetic components contribute to the observed association. We therefore investigated the co-aggregation of stress-related disorders and autoimmune diseases in individuals and their family members in the Swedish population.Methods: We identified 4,123,631 individuals born in Sweden between 1953 and 1993. Based on information from the Multi-Generation Register, we conducted cohorts of relatives of varying relatedness. Logistic regression was used to estimate the association between clinical ascertained stress-related disorders (i.e., acute stress reaction, posttraumatic stress disorder [PTSD], adjustment disorder, and other severe stress reactions) and autoimmune diseases (36 different types) in individuals and in families, presenting relative risks as odds ratios (ORs).Results: Individuals with stress-related disorder were at high er risk of having autoimmune diseases compared with individuals who did nothave stress-related disorder (OR = 1.66, 95% confidence intervals (CI) 1.63–1.69). Within families, the association seemed strongest between monozygotic twins (OR = 1.47, 95% CI 1.07–2.03), and then decreased with descending dyads of familial/genetic relatedness ̄OR was 1.28 (95% CI 0.97–1.67), 1.16 (95% CI 1.14–1.18), 1.05 (95% CI 1.02–1.09), 1.06 (95% CI 1.03–1.10), 1.05 (95% CI 1.04–1.06), and 1.00 (95% CI 0.98–1.04) for dizygotic twins, full siblings, maternal half siblings, paternal half siblings, full cousins, and half cousins, respectively. Further analyses on PTSD and autoimmune diseases obtained similar estimates.Conclusion: The pattern of the association across twin zygosity and varying familial relatedness supports the hypothesis of a genetic overlap between stress-related disorders and autoimmune diseases which warrants further exploration.
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| 8. |
- Sujan, Ayesha C., et al.
(author)
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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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In: Behavior Genetics. - New York, USA : Springer. - 0001-8244 .- 1573-3297. ; 46:3, s. 431-456
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Journal article (peer-reviewed)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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| 9. |
- Yao, Shuyang, et al.
(author)
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Risk of being convicted of theft and other crimes in anorexia nervosa and bulimia nervosa : A prospective cohort study in a Swedish female population
- 2017
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In: International Journal of Eating Disorders. - : John Wiley & Sons. - 0276-3478 .- 1098-108X. ; 50:9, s. 1095-1103
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Journal article (peer-reviewed)abstract
- Objective: We examined epidemiological associations between anorexia nervosa (AN) and bulimia nervosa (BN) and risks of committing theft and other crimes in a nationwide female population.Method: Females born in Sweden during 1979-1998 (N=957,106) were followed from age 15 for up to 20 years using information on clinically diagnosed AN and BN (exposures), convictions of theft and other crimes (outcomes), psychiatric comorbidities, and familial relatedness from Swedish national registers. We estimated hazard ratios (HRs) of criminality in exposed versus unexposed females using Cox proportional hazards regressions and explored how comorbidities and unmeasured familial factors explained the associations.Results: The cumulative incidence of convictions of theft (primarily petty theft) and other crimes was higher in exposed females (AN: 11.60% theft, 7.39% other convictions; BN: 17.97% theft, 13.17% other convictions) than in unexposed females (approximate to 5% theft, approximate to 6% other convictions). The significantly increased risk of being convicted of theft in exposed females (AN: HR=2.51, 95% confidence interval=[2.29, 2.74], BN: 4.31 [3.68, 5.05]) was partially explained by comorbidities; unmeasured familial factors partially explained the association with convictions of theft in BN but not in AN. Females with BN had a doubled risk of convictions of other crimes, which was partially explained by comorbidities.Discussion: Individuals with eating disorders had increased risk for convictions of theft and potentially other crimes. Results underscore the importance of regular forensic screening and encourage research on mechanisms underlying the relation between crime and eating disorder psychopathology and efforts to determine how best to address such relation in treatment.
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| 10. |
- Silventoinen, Karri, et al.
(author)
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Education in twins and their parents across birth cohorts over 100 years : an individual-level pooled analysis of 42 twin cohorts
- 2017
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In: Twin Research and Human Genetics. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1832-4274 .- 1839-2628.
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Journal article (peer-reviewed)abstract
- Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990-1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.
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