| 1. |
|
|
| 2. |
|
|
| 3. |
- Almqvist, Catarina, et al.
(author)
-
LifeGene - A large prospective population-based study of global relevance
- 2011
-
In: European Journal of Epidemiology. - Stockholm : Springer Science and Business Media LLC. - 0393-2990 .- 1573-7284. ; 26:1, s. 67-77
-
Journal article (peer-reviewed)abstract
- Studying gene-environment interactions requires that the amount and quality of the lifestyle data is comparable to what is available for the corresponding genomic data. Sweden has several crucial prerequisites for comprehensive longitudinal biomedical research, such as the personal identity number, the universally available national health care system, continuously updated population and health registries and a scientifically motivated population. LifeGene builds on these strengths to bridge the gap between basic research and clinical applications with particular attention to populations, through a unique design in a research-friendly setting. LifeGene is designed both as a prospective cohort study and an infrastructure with repeated contacts of study participants approximately every 5 years. Index persons aged 18-45 years old will be recruited and invited to include their household members (partner and any children). A comprehensive questionnaire addressing cutting-edge research questions will be administered through the web with short follow-ups annually. Biosamples and physical measurements will also be collected at baseline, and re-administered every 5 years thereafter. Event-based sampling will be a key feature of LifeGene. The household-based design will give the opportunity to involve young couples prior to and during pregnancy, allowing for the first study of children born into cohort with complete pre-and perinatal data from both the mother and father. Questions and sampling schemes will be tailored to the participants' age and life events. The target of LifeGene is to enrol 500,000 Swedes and follow them longitudinally for at least 20 years.
|
|
| 4. |
- Almqvist, Catarina, et al.
(author)
-
The impact of birth mode of delivery on childhood asthma and allergic diseases : a sibling study
- 2012
-
In: Clinical and experimental allergy. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1365-2222 .- 0954-7894.
-
Journal article (peer-reviewed)abstract
- Background: Caesarean section (CS) has been reported to increase the risk of asthma in offspring. This may be due to that infants delivered by CS are unexposed to vaginal flora, according to the ‘hygiene hypothesis’. Objective: Our aim was to investigate if CS increases risk of childhood asthma, and if the risk increase remains after adjustment for familial confounding using sibling design. Methods: A register-based cohort study with 87 500 Swedish sibling pairs was undertaken. Asthma outcome variables were collected from national health registers as diagnosis or asthma medication (ICD-10 J45-J46; ATC code R03) during the 10th or 13th year of life (year of follow-up). Mode of delivery and confounders were retrieved from the Medical Birth Register. The data were analysed both as a cohort and with sibling control analysis which adjusts for unmeasured familial confounding. Results: In the cohort analyses, there was an increased risk of asthma medication and asthma diagnosis during year of follow-up in children born with CS (adjusted ORs, 95% CI 1.13, 1.04–1.24 and 1.10, 1.03–1.18 respectively). When separating between emergency and elective CS the effect on asthma medication remained for emergency CS, but not for elective CS, while both groups had significant effects on asthma diagnosis compared with vaginal delivery. In sibling control analyses, the effect of elective CS on asthma disappeared, while similar but non-significant ORs of medication were obtained for emergency CS. Conclusions and Clinical Relevance: An increased risk of asthma medication in the group born by emergency CS, but not elective, suggests that there is no causal effect due to vaginal microflora. A more probable explanation should be sought in the indications for emergency CS.
|
|
| 5. |
- Ballardini, Natalia, et al.
(author)
-
Development and comorbidity of eczema, asthma and rhinitis to age 12 : data from the BAMSE birth cohort
- 2012
-
In: Allergy. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0105-4538 .- 1398-9995.
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Allergy-related diseases are a public health issue, but knowledge on development and comorbidity among children is scarce. The aim was to study the development of eczema, asthma and rhinitis in relation to sex and parental allergy, in a population-based cohort, during childhood. METHODS: At 1, 2, 4, 8 and 12 years, parental questionnaires were used to obtain data on allergy-related diseases. Complete data for all five follow-up occasions were available from 2916 children. Odds ratios for the risk of any allergy-related disease in relation to heredity and sex were calculated using generalized estimating equations. RESULTS: At 12 years, 58% of the children had had eczema, asthma and/or rhinitis at some time. Disease turnover was high for all three diseases throughout the study. Comorbidity increased with age, and at 12 years, 7.5% of all the children were affected by at least two allergy-related diseases. Parental allergy was associated with increased comorbidity and more persistent disease and increased the risk of having any allergy-related disease (adjusted OR 1.76; 95% CI 1.57-1.97) up to 12 years. Male sex was associated with an increased risk throughout childhood. Boys and girls did not differ in disease persistence, and for comorbidity, the differences were minor. CONCLUSIONS: Allergy-related diseases may affect a majority of children. Eczema, asthma and rhinitis develop dynamically throughout childhood, and allergic comorbidity is common. These findings indicate that allergy-related diseases should be neither seen nor studied as isolated entities.
|
|
| 6. |
- Brew, Bronwyn K, et al.
(author)
-
Breastfeeding, asthma, and allergy : a tale of two cities
- 2012
-
In: Pediatric Allergy and Immunology. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0905-6157. ; 23:1, s. 75-82
-
Journal article (peer-reviewed)abstract
- BACKGROUND: The effect of breastfeeding duration on subsequent asthma and allergy remains the subject of much controversy. OBJECTIVE: To investigate whether differences in study design or disease-related exposure modification were the cause of the differences in study findings. METHOD: The data from two cohorts, the Childhood Asthma Prevention Study (CAPS) from Australia and the Barn Allergi Miljo Stockholm cohort from Sweden, which had reported different findings on the association between breastfeeding and asthma, were combined. For this analysis, the definitions for breastfeeding, asthma, and allergy were harmonized. Subjects were included if they had at least one parent with wheeze or asthma and had a gestational age of more than 36 wks (combined n = 882). The risk of disease-related exposure modification was assessed using survival analysis. RESULTS: Breastfeeding reduced the risk of asthma at 4/5 and 8 yrs of age in children with a family history of asthma. The effect was stronger in the Swedish cohort. Breastfeeding had no effect on the prevalence of sensitization to inhaled allergens in this cohort with a family history of asthma but was a risk factor for sensitization to cow's milk, peanuts, and eggs in the CAPS cohort at 4/5 yrs and in the combined cohort at 8 yrs. There was no evidence to support the existence of disease-related exposure modification in either cohort. CONCLUSION: These findings point to the importance of harmonization of features of study design, including subject selection criteria and variable definitions, in resolving epidemiological controversies such as those surrounding the impact of breastfeeding on asthma and allergic sensitization.
|
|
| 7. |
- Chang, Zheng, et al.
(author)
-
Maternal age at childbirth and risk for ADHD in offspring : a population-based cohort study
- 2014
-
In: International Journal of Epidemiology. - Oxford, United Kingdom : Oxford University Press. - 0300-5771 .- 1464-3685. ; 43:6, s. 1815-1824
-
Journal article (peer-reviewed)abstract
- Background: Women who give birth at younger ages (e.g. teenage mothers) are more likely to have children who exhibit behaviour problems, such as attention-deficit/hyperactivity disorder (ADHD). However, it is not clear whether young maternal age is causally associated with poor offspring outcomes or confounded by familial factors.Methods: The association between early maternal age at childbirth and offspring ADHD was studied using data from Swedish national registers. The sample included all children born in Sweden between 1988 and 2003 (N = 1 495 543), including 30 674 children with ADHD. We used sibling- and cousin-comparisons to control for unmeasured genetic and environmental confounding. Further, we used a children-of-siblings model to quantify the genetic and environmental contribution to the association between maternal age and offspring ADHD.Results: Maternal age at first birth (MAFB) was associated with offspring ADHD. Teenage childbirth (<20 years) was associated with 78% increased risk of ADHD. The association attenuated in cousin-comparison, suggesting unmeasured familial confounding. The children-of-siblings model indicated that the association between MAFB and ADHD was mainly explained by genetic confounding.Conclusions: All children born to mothers who bore their first child early in their reproductive lives were at increased risk of ADHD. The association was mainly explained by genetic factors transmitted from mothers to their offspring that contribute to both age at childbirth and ADHD in offspring. Our results highlight the importance of using family-based designs to understand how early life circumstances affect child development.
|
|
| 8. |
- D'Onofrio, Brian M., et al.
(author)
-
Paternal age at childbearing and offspring psychiatric and academic morbidity
- 2014
-
In: JAMA psychiatry. - Chicago, United States : American Medical Association. - 2168-6238 .- 2168-622X. ; 71:4, s. 432-438
-
Journal article (peer-reviewed)abstract
- Importance: Advancing paternal age is associated with increased genetic mutations during spermatogenesis, which research suggests may cause psychiatric morbidity in the offspring. The effects of advancing paternal age at childbearing on offspring morbidity remain unclear, however, because of inconsistent epidemiologic findings and the inability of previous studies to rigorously rule out confounding factors.Objective: To examine the associations between advancing paternal age at childbearing and numerous indexes of offspring morbidity.Design, setting and participants: We performed a population-based cohort study of all individuals born in Sweden in 1973-2001 (N = 2,615,081), with subsets of the data used to predict childhood or adolescent morbidity. We estimated the risk of psychiatric and academic morbidity associated with advancing paternal age using several quasi-experimental designs, including the comparison of differentially exposed siblings, cousins, and first-born cousins.Exposure: Paternal age at childbearing.Main outcomes and measures: Psychiatric (autism, attention-deficit/hyperactivity disorder, psychosis, bipolar disorder, suicide attempt, and substance use problem) and academic (failing grades and low educational attainment) morbidity.Results: In the study population, advancing paternal age was associated with increased risk of some psychiatric disorders (eg, autism, psychosis, and bipolar disorders) but decreased risk of the other indexes of morbidity. In contrast, the sibling-comparison analyses indicated that advancing paternal age had a dose-response relationship with every index of morbidity, with the magnitude of the associations being as large or larger than the estimates in the entire population. Compared with offspring born to fathers 20 to 24 years old, offspring of fathers 45 years and older were at heightened risk of autism (hazard ratio [HR] = 3.45; 95% CI, 1.62-7.33), attention-deficit/hyperactivity disorder (HR = 13.13; 95% CI, 6.85-25.16), psychosis (HR = 2.07; 95% CI, 1.35-3.20), bipolar disorder (HR = 24.70; 95% CI, 12.12-50.31), suicide attempts (HR = 2.72; 95% CI, 2.08-3.56), substance use problems (HR = 2.44; 95% CI, 1.98-2.99), failing a grade (odds ratio [OR] = 1.59; 95% CI, 1.37-1.85), and low educational attainment (OR = 1.70; 95% CI, 1.50-1.93) in within-sibling comparisons. Additional analyses using several quasi-experimental designs obtained commensurate results, further strengthening the internal and external validity of the findings.Conclusions and relevance: Advancing paternal age is associated with increased risk of psychiatric and academic morbidity, with the magnitude of the risks being as large or larger than previous estimates. These findings are consistent with the hypothesis that new genetic mutations that occur during spermatogenesis are causally related to offspring morbidity.
|
|
| 9. |
- Falhammar, Henrik, et al.
(author)
-
Increased mortality in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency
- 2014
-
In: The Journal of Clinical Endocrinology & Metabolism. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0021-972X .- 1945-7197.
-
Journal article (peer-reviewed)abstract
- Context: Reports on mortality in patients with congenital adrenal hyperplasia (CAH) are lacking. Objective: To study mortality and causes of death in CAH. Design, Setting and Participants: We studied patients with CAH (21-hydroxylase deficiency, n=588; CYP21A2 mutations known, >80%), and compared them with controls (n=58800). Data were derived through linkage of national population-based registers. Main Outcome Measures: Mortality and causes of death. Results: The mean age of death was 41.2±26.9 years in CAH patients and 47.7±27.7 years in controls (P<0.001). Among CAH patients 23 (3.9%) had deceased compared to 942 (1.6%) of controls. The hazard ratio (and 95% confidence interval) of death was 2.3(1.2-4.3) in CAH males and 3.5(2.0-6.0) in CAH females. Including only patients born 1952-2009, gave similar total results but only patients with salt-wasting or with unclear phenotype had an increased mortality. The causes of death in CAH patients were adrenal crisis (42%), cardiovascular (32%), cancer (16%), and suicide (10%). There were seven additional deaths in CAH individuals with incomplete or reused personal identification number that could not be analyzed using linkage of registers. Of the latter all except one were deceased before the introduction of neonatal screening in 1986 and most of them in the first weeks of life, probably in an adrenal crisis. Conclusions: CAH is a potentially lethal condition and was associated with excess mortality due to adrenal crisis. The salt-wasting phenotype seemed to have worse outcome also in children and adults due to adrenal crisis and not only before the introduction of neonatal screening.
|
|
| 10. |
- Fang, Fang, et al.
(author)
-
Maternal bereavement and childhood asthma-analyses in two large samples of Swedish children
- 2011
-
In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:11, s. e27202-
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Prenatal factors such as prenatal psychological stress might influence the development of childhood asthma. METHODOLOGY AND PRINCIPAL FINDINGS: We assessed the association between maternal bereavement shortly before and during pregnancy, as a proxy for prenatal stress, and the risk of childhood asthma in the offspring, based on two samples of children 1-4 (n = 426 334) and 7-12 (n = 493 813) years assembled from the Swedish Medical Birth Register. Exposure was maternal bereavement of a close relative from one year before pregnancy to child birth. Asthma event was defined by a hospital contact for asthma or at least two dispenses of inhaled corticosteroids or montelukast. In the younger sample we calculated hazards ratios (HRs) of a first-ever asthma event using Cox models and in the older sample odds ratio (ORs) of an asthma attack during 12 months using logistic regression. Compared to unexposed boys, exposed boys seemed to have a weakly higher risk of first-ever asthma event at 1-4 years (HR: 1.09; 95% confidence interval [CI]: 0.98, 1.22) as well as an asthma attack during 12 months at 7-12 years (OR: 1.10; 95% CI: 0.96, 1.24). No association was suggested for girls. Boys exposed during the second trimester had a significantly higher risk of asthma event at 1-4 years (HR: 1.55; 95% CI: 1.19, 2.02) and asthma attack at 7-12 years if the bereavement was an older child (OR: 1.58; 95% CI: 1.11, 2.25). The associations tended to be stronger if the bereavement was due to a traumatic death compared to natural death, but the difference was not statistically significant. CONCLUSIONS/SIGNIFICANCE: Our results showed some evidence for a positive association between prenatal stress and childhood asthma among boys but not girls.
|
|
