Nugroho Harry Susanto1, Don Vicendese2, Agus Salim3, Adrian J Lowe4, Shyamali C Dharmage4, Rachel Tham4, Caroline Lodge4, Frances Garden5, Katie Allen6, Cecilie Svanes7, Joachim Heinrich8, Michael J Abramson9, Bircan Erbas10. 1. School of Public Health, La Trobe University, Bundoora, Vic, Australia; Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Jakarta, Indonesia; Epidemiology and Biostatistics Division, Public Health Department, Faculty of Medicine, Padjadjaran University, Bandung, Indonesia. 2. Cancer Council of Victoria, Melbourne, Vic 3004, Australia. 3. Department of Mathematics and Statistics, La Trobe University, Bundoora, Vic, Australia. 4. Allergy and Lung Health Unit, School of Population and Global Health, The University of Melbourne, Australia. 5. Woolcock Institute of Medical Research, The University of Sydney, Glebe, New South Wales, Australia; South Western Sydney Clinical School, University of New South Wales, Liverpool, New South Wales, Australia; Ingham Institute of Applied Medical Research, University of New South Wales, Liverpool, New South Wales, Australia. 6. Department of Allergy and Clinical Immunology and Department of Gastroenterology and Clinical Nutrition, Royal Children's Hospital, Melbourne 3052, Australia. 7. Centre for International Health, University of Bergen, Norway and Department Occupational Medicine, Haukelan, University Hospital, Bergen, Norway. 8. Institute of Epidemiology I, Helmholtz Zentrum München - German Research Center for Environmental Health, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany; Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Inner City Clinic, University Hospital of Munich (LMU), Munich, Germany. 9. School of Public Health and Preventive Medicine, Monash University, Melbourne. 10. School of Public Health, La Trobe University, Bundoora, Vic, Australia. Electronic address: b.erbas@latrobe.edu.au.
Abstract
BACKGROUND: Elevated cord blood IgE is important on the pathway to allergic disease. The association between season of birth and infant cord blood IgE is not well-established. Study findings differ on which birth season is associated with higher cord blood IgE risk and its magnitude. We conducted a systematic review and meta-analysis of studies on season of birth and cord blood IgE. METHODS: We searched Medline, Web of Science, Scopus and ProQuest Health databases, and reviewed reference lists of articles that met the inclusion criteria. All included studies measured IgE as a binary variable using various cut-off values. We performed multivariate-random-effects meta-analysis to handle an exposure with multiple categories of Season of Birth. RESULTS: Our search identified 275 records and 10 had sufficient data to be included in a meta-analysis. Relative to summer, winter birth had the greatest odds of high IgE (≥ 0.1IU/ml), meta-analysis OR = 1.24 (95%CI: 1.01-1.52). A similar OR, was found for IgE ≥ 0.5 IU/ml, OR = 1.30 (95%CI: 0.99-1.71). CONCLUSIONS: A winter season of birth was associated with statistically significant higher odds of elevated cord blood IgE at cut-off ≥ 0.1IU/ml but borderline at cut-off ≥ 0.5IU/ml. This winter effect is likely to be a marker for a range of other environmental exposures during specific stages of pregnancy, such as aeroallergen exposures, maternal infections and vitamin D levels. Further research is required to support our finding and to identify the exact mechanisms that lead to the winter season of birth effect on circulating IgE levels, as this may have implications for allergic disease prevention.
BACKGROUND: Elevated cord blood IgE is important on the pathway to allergic disease. The association between season of birth and infant cord blood IgE is not well-established. Study findings differ on which birth season is associated with higher cord blood IgE risk and its magnitude. We conducted a systematic review and meta-analysis of studies on season of birth and cord blood IgE. METHODS: We searched Medline, Web of Science, Scopus and ProQuest Health databases, and reviewed reference lists of articles that met the inclusion criteria. All included studies measured IgE as a binary variable using various cut-off values. We performed multivariate-random-effects meta-analysis to handle an exposure with multiple categories of Season of Birth. RESULTS: Our search identified 275 records and 10 had sufficient data to be included in a meta-analysis. Relative to summer, winter birth had the greatest odds of high IgE (≥ 0.1IU/ml), meta-analysis OR = 1.24 (95%CI: 1.01-1.52). A similar OR, was found for IgE ≥ 0.5 IU/ml, OR = 1.30 (95%CI: 0.99-1.71). CONCLUSIONS: A winter season of birth was associated with statistically significant higher odds of elevated cord blood IgE at cut-off ≥ 0.1IU/ml but borderline at cut-off ≥ 0.5IU/ml. This winter effect is likely to be a marker for a range of other environmental exposures during specific stages of pregnancy, such as aeroallergen exposures, maternal infections and vitamin D levels. Further research is required to support our finding and to identify the exact mechanisms that lead to the winter season of birth effect on circulating IgE levels, as this may have implications for allergic disease prevention.
Authors: Amelia K Wesselink; Lauren A Wise; Elizabeth E Hatch; Ellen M Mikkelsen; Henrik T Sørensen; Anders H Riis; Craig J McKinnon; Kenneth J Rothman Journal: Hum Reprod Date: 2020-03-27 Impact factor: 6.918