Browsing by Author "Joner, G."

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    Birthweight and the risk of childhood-onset type 1 diabetes : A meta-analysis of observational studies using individual patient data
    (2010-04) Cardwell, C. R.; Stene, L. C.; Joner, G.; Davis, E. A.; Cinek, O.; Rosenbauer, J.; Ludvigsson, J.; Castell, C.; Svensson, J.; Goldacre, M. J.; Waldhoer, T.; Polanska, J.; Gimeno, S. G.A.; Chuang, L. M.; Parslow, R. C.; Wadsworth, E. J.K.; Chetwynd, A.; Pozzilli, P.; Brigis, G.; Urbonaite, B.; Šipetić, S.; Schober, E.; Ionescu-Tirgoviste, C.; De Beaufort, C. E.; Stoyanov, D.; Buschard, K.; Patterson, C. C.; Department of Public Health and Epidemiology
    Aims/hypothesis: We investigated whether children who are heavier at birth have an increased risk of type 1 diabetes. Methods: Relevant studies published before February 2009 were identified from literature searches using MEDLINE, Web of Science and EMBASE. Authors of all studies containing relevant data were contacted and asked to provide individual patient data or conduct pre-specified analyses. Risk estimates of type 1 diabetes by category of birthweight were calculated for each study, before and after adjustment for potential confounders. Meta-analysis techniques were then used to derive combined ORs and investigate heterogeneity between studies. Results: Data were available for 29 predominantly European studies (five cohort, 24 case-control studies), including 12,807 cases of type 1 diabetes. Overall, studies consistently demonstrated that children with birthweight from 3.5 to 4 kg had an increased risk of diabetes of 6% (OR 1.06 [95% CI 1.01-1.11]; p=0.02) and children with birthweight over 4 kg had an increased risk of 10% (OR 1.10 [95% CI 1.04-1.19]; p=0.003), compared with children weighing 3.0 to 3.5 kg at birth. This corresponded to a linear increase in diabetes risk of 3% per 500 g increase in birthweight (OR 1.03 [95% CI 1.00-1.06]; p=0.03). Adjustments for potential confounders such as gestational age, maternal age, birth order, Caesarean section, breastfeeding and maternal diabetes had little effect on these findings. Conclusions/interpretation: Children who are heavier at birth have a significant and consistent, but relatively small increase in risk of type 1 diabetes.
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    Caesarean section is associated with an increased risk of childhood-onset type 1 diabetes mellitus : A meta-analysis of observational studies
    (2008-05) Cardwell, C. R.; Stene, L. C.; Joner, G.; Cinek, O.; Svensson, J.; Goldacre, M. J.; Parslow, R. C.; Pozzilli, P.; Brigis, G.; Stoyanov, D.; Urbonaitė, B.; Šipetić, S.; Schober, E.; Ionescu-Tirgoviste, C.; Devoti, G.; De Beaufort, C. E.; Buschard, K.; Patterson, C. C.; Department of Public Health and Epidemiology
    Aims/hypothesis: The aim of this study was to investigate the evidence of an increased risk of childhood-onset type 1 diabetes in children born by Caesarean section by systematically reviewing the published literature and performing a meta-analysis with adjustment for recognised confounders. Methods: After MEDLINE, Web of Science and EMBASE searches, crude ORs and 95% CIs for type 1 diabetes in children born by Caesarean section were calculated from the data reported in each study. Authors were contacted to facilitate adjustments for potential confounders, either by supplying raw data or calculating adjusted estimates. Meta-analysis techniques were then used to derive combined ORs and to investigate heterogeneity between studies. Results: Twenty studies were identified. Overall, there was a significant increase in the risk of type 1 diabetes in children born by Caesarean section (OR 1.23, 95% CI 1.15-1.32, p<0.001). There was little evidence of heterogeneity between studies (p=0.54). Seventeen authors provided raw data or adjusted estimates to facilitate adjustments for potential confounders. In these studies, there was evidence of an increase in diabetes risk with greater birthweight, shorter gestation and greater maternal age. The increased risk of type 1 diabetes after Caesarean section was little altered after adjustment for gestational age, birth weight, maternal age, birth order, breast-feeding and maternal diabetes (adjusted OR 1.19, 95% CI 1.04-1.36, p=0.01). Conclusions/interpretation: This analysis demonstrates a 20% increase in the risk of childhood-onset type 1 diabetes after Caesarean section delivery that cannot be explained by known confounders.