| 1. |
- Gong, Tong, et al.
(författare)
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Perinatal exposure to traffic-related air pollution and autism spectrum disorders
- 2016
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Ingår i: Environmental Health Perspectives. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0091-6765. ; 125:1, s. 119-126
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies from the United States indicate that exposure to air pollution in early life is associated with autism spectrum disorders (ASD) in children, but the evidence is not consistent with European data. Objective: We aimed to investigate the association between exposure to air pollution from road traffic and the risk of ASD in children, with careful adjustment for socioeconomic and other confounders. Method: Children born and residing in Stockholm, Sweden, during 1993–2007 with an ASD diagnosis were identified through multiple health registers and classified as cases (n = 5,136). A randomly selected sample of 18,237 children from the same study base constituted controls. Levels of nitrogen oxides (NOx) and particulate matter with diameter ≤ 10 μm (PM10) from road traffic were estimated at residential addresses during mother’s pregnancy and the child’s first year of life by dispersion models. Odds ratios (OR) and 95% confidence intervals (CI) for ASD with or without intellectual disability (ID) were estimated using logistic regression models after conditioning on municipality and calendar year of birth as well as adjustment for potential confounders. Result: Air pollution exposure during the prenatal period was not associated with ASD overall (OR = 1.00; 95% CI: 0.86, 1.15 per 10-μg/m3 increase in PM10 and OR = 1.02; 95% CI: 0.94, 1.10 per 20-μg/m3 increase in NOx during mother’s pregnancy). Similar results were seen for exposure during the first year of life, and for ASD in combination with ID. An inverse association between air pollution exposure and ASD risk was observed among children of mothers who moved to a new residence during pregnancy. Conclusion: Early-life exposure to low levels of NOx and PM10 from road traffic does not appear to increase the risk of ASD.
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| 2. |
- Ahlén, Katia M, et al.
(författare)
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Antibiotic treatment and length of hospital stay in relation to delivery mode and prematurity
- 2016
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Ingår i: PLOS One. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1932-6203.
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To investigate how 1) maternal delivery mode and 2) prematurity in infants are associated to antibiotic treatment and length of hospital stay. METHODS: Women having given birth and infants 0-12 months discharged from hospital between July 2005 and November 2011 were identified from the Swedish National Patient Register. Medical records were reviewed for 203 women and 527 infants. The risk ratio (RR) between antibiotic treatment and 1) delivery mode in women; 2) prematurity in infants was calculated. Length of stay and days of antibiotic therapy were compared by Wilcoxon rank-sum test. RESULTS: Women: There was an association between emergency caesarean section (CS) and antibiotic treatment (RR 5.0 95% confidence interval (CI) 2.2-11.5), but not for elective CS. Length of stay was longer for CS (emergency and elective) compared to vaginal delivery (p<0.01). Infants: RR for antibiotic treatment in preterm compared to term infants was 1.4 (95% CI 1.0-1.9). Length of stay (p<0.01), but not days of therapy (p = 0.17), was higher in preterm compared to term infants. CONCLUSION: We found that emergency CS increased the probability of maternal antibiotic treatment during hospitalisation, but no difference was found between term and preterm infants. The results are well aligned with current guidelines and may be considered in future studies on the effects of antibiotics.
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| 3. |
- Almqvist, Catarina, et al.
(författare)
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Association between parental age and asthma in a population-based register study
- 2015
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Ingår i: Journal of Allergy and Clinical Immunology. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0091-6749 .- 1097-6825.
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Tidskriftsartikel (refereegranskat)abstract
- In a nationwide population-based study with family design, we found an association between decreasing parental age and asthma in early childhood. The effect was independent of familial and potentially confounding factors.
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| 4. |
- Almqvist, Catarina, et al.
(författare)
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Cohort profile : Swedish Twin Study on Prediction and Prevention of Asthma (STOPPA)
- 2015
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Ingår i: Twin Research and Human Genetics. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1832-4274 .- 1839-2628.
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Tidskriftsartikel (refereegranskat)abstract
- Asthma is a common childhood disease and several risk factors have been identified, however the impact of genes and environment is not fully understood. The aim of the Swedish Twin study On Prediction and Prevention of Asthma (STOPPA) is to identify environmental (birth characteristics and early life) and genetic (including epigenetic) factors as determinants for asthmatic disease. Based on the Child and Adolescent Twin Study in Sweden (parental interview at 9 or 12 years, N~23,900) and an asthma and/or wheezing algorithm, we identified a sample of monozygotic (MZ) and dizygotic (DZ) same-sexed twin pairs. The twin pairs were identified as asthma concordant (ACC), asthma discordant (ADC) and healthy concordant (HCC). A sample of 9- to 14-year-old twins and their parents were invited to participate in a clinical examination. Background characteristics were collected in questionnaires and obtained from the National Health Registers. A clinical examination was performed to test lung function and capacity (spirometry with reversibility test and exhaled nitric oxide) and collect blood (serology and DNA), urine (metabolites), feces (microbiota) and saliva (cortisol). In total, 376 twin pairs (752 individual twins) completed the study, response rate 52%. All participating twins answered the questionnaire and >90% participated in lung function testing, blood and saliva sampling. This article describes the design, recruitment, data collection, measures, background characteristics as well as ongoing and planned analyses in STOPPA. Potential gains of the study include the identification of biomarkers, the emergence of candidates for drug development and new leads for prevention of asthma and allergic disease.
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| 5. |
- Almqvist, Catarina, et al.
(författare)
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Individual maternal and child exposure to antibiotics in hospital : a national population-based validation study
- 2015
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Ingår i: Acta Paediatrica: Nurturing the Child. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0803-5253 .- 1651-2227.
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Exposure to antibiotics in early life may affect future health. Most antibiotics are prescribed in outpatient care, but inpatient exposure is also important. We estimated how specific diagnoses in hospitals corresponded to individual antibiotic exposure. Methods: All pregnant women and children from birth to five-years-of-age with infectious diseases and common inpatient diagnoses between July 2005 and November 2011were identified from the Swedish National Patient Register. Random samples of individuals from pre-defined groups were drawn and medical records received from the clinics were manually reviewed for antibiotics. Results: Medical records for 4,319 hospital visits were requested and 3,797 (88%) were received. A quarter (25%) of children diagnosed as premature had received antibiotics and in children from one to five-years-of-age, diagnoses associated with bacterial infections were more commonly treated with antibiotics (62.4-90.6%) than those associated with viruses (6.3-22.2%). Pregnant women who had undergone a Caesarean section were more likely to be treated with antibiotics than those who had had a vaginal delivery (40.1% versus 11.1%). Conclusions: This study defines the proportion of new mothers and young children who received individual antibiotic treatment for specific inpatient diagnoses in Sweden and provides a useful basis for future studies focusing on antibiotic use.
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| 6. |
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| 7. |
- Almqvist, Catarina, et al.
(författare)
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Season of birth, childhood asthma and allergy in a nationwide cohort : Mediation through lower respiratory infections
- 2020
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Ingår i: Clinical and Experimental Allergy. - Stockholm : Wiley. - 0954-7894 .- 1365-2222. ; 50:2, s. 222-230
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundPrevious studies have suggested an association between season of birth and risk of childhood asthma and allergic disease. The association may be modified by birth year and region, or mediated by respiratory tract infections.ObjectiveWe aimed to estimate the association between season of birth and risk of childhood asthma/wheeze or allergic rhinoconjunctivitis in a population‐based setting, and the mediating effect of lower respiratory infections.MethodsTwo population‐based cohorts were identified from the nationwide Swedish Medical Birth, Patient and Prescribed Drug Registers. The association between birth month/season and asthma/wheeze incidence was analysed using Cox proportional regression in the younger cohort born 2005‐2010 (n = 582 494) and asthma/allergic rhinoconjunctivitis prevalence during the 7th year of life using log‐binomial models in the older cohort born 2001‐2004 (n = 367 583). Interactions were formally tested. Mediation analyses to address the effect of lower respiratory infections were performed in the older cohort using the R package “medflex.”ResultsChildren born during fall and winter had an increased risk of asthma/wheeze after 2 years of age in the younger cohort: hazard ratio 1.24 (95% confidence interval, CI 1.17, 1.33) for winter and risk of prevalent asthma during their 7th year of life in the older cohort; prevalence ratio (PR) 1.12 (95% CI 1.08, 1.16) for winter. These estimates were partly mediated by lower respiratory infections; the indirect effect for winter compared with summer was PR 1.03 (95% CI 1.03, 1.04). The association was similar for allergic rhinoconjunctivitis in the 7th year of life, but not mediated by respiratory infections.ConclusionWe found that the association between season of birth and risk of childhood asthma/wheeze, but not allergic rhinoconjunctivitis, is partly mediated through lower respiratory infections.Clinical relevanceThis has important implications for patient care, such as asthma management programmes to notify timing of seasonality for viral respiratory tract infections.
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| 8. |
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| 9. |
- Almqvist, Catarina, et al.
(författare)
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The impact of birth mode of delivery on childhood asthma and allergic diseases : a sibling study
- 2012
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Ingår i: Clinical and experimental allergy. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1365-2222 .- 0954-7894.
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Tidskriftsartikel (refereegranskat)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.
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| 10. |
- Altman, Daniel, et al.
(författare)
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The genetic and environmental contribution to the occurrence of bladder pain syndrome: an empirical approach in a nationwide population sample.
- 2011
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Ingår i: European urology. - : Elsevier BV. - 1873-7560 .- 0302-2838. ; 59:2, s. 280-5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The aetiology of bladder pain syndrome (BPS) remains poorly understood, and a number of pathogenic mechanisms have been proposed. The importance of genetic factors for BPS is receiving growing attention, but data so far are of a preliminary nature. OBJECTIVE: To empirically assess the genetic and environmental contribution to BPS in a population-based sample of twins. DESIGN, SETTING, AND PARTICIPANTS: The study included >25 000 twins born between 1959 and 1985. Individuals with BPS were identified using latent class cluster analysis (LCCA) based on self-reported symptoms from a nationwide screening for complex diseases in the Swedish Twin Registry. By comparing monozygotic and dizygotic twins, we estimated twin similarity and the relative proportions of phenotypic variance resulting from genetic and environmental factors. MEASUREMENTS: Twin similarity was measured. RESULTS AND LIMITATIONS: The LCCA yielded an overall BPS prevalence of 1.1% and 2.4% for males and females, respectively. In males, the contribution of genetic effects to BPS could not be assessed because of the small number of concordant twin pairs. In women, twin similarity estimates indicated a genetic component for the aetiology of BPS, but genetic factors contributed less than one-third of the total variation in susceptibility to BPS. Nonshared environmental factors accounted for more than two-thirds of the variance, whereas early nongenetic factors shared within the family were of little or no consequence to the risk of developing BPS later in life. Use of self-reported symptoms to define the disease phenotype is a limitation of the study. CONCLUSIONS: The influence of environmental factors in the development of BPS in women is substantial, whereas genetic influences are of only modest importance for the possibility of developing the disease.
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