Mother's education and offspring asthma risk in 10 European cohort studies
Highly prevalent and typically beginning in childhood, asthma is a burdensome disease, yet the risk factors for this condition are not clarified. To enhance understanding, this study assessed the cohort-specific and pooled risk of maternal education on asthma in children aged 3–8 across 10 European countries. Data on 47,099 children were obtained from prospective birth cohort studies across 10 European countries. We calculated cohort-specific prevalence difference in asthma outcomes using the relative index of inequality (RII) and slope index of inequality (SII). Results from all countries were pooled using random-effects meta-analysis procedures to obtain mean RII and SII scores at the European level. Final models were adjusted for child sex, smoking during pregnancy, parity, mother's age and ethnicity. The higher the score the greater the magnitude of relative (RII, reference 1) and absolute (SII, reference 0) inequity. The pooled RII estimate for asthma risk across all cohorts was 1.46 (95% CI 1.26, 1.71) and the pooled SII estimate was 1.90 (95% CI 0.26, 3.54). Of the countries examined, France, the United Kingdom and the Netherlands had the highest prevalence's of childhood asthma and the largest inequity in asthma risk. Smaller inverse associations were noted for all other countries except Italy, which presented contradictory scores, but with small effect sizes. Tests for heterogeneity yielded significant results for SII scores. Overall, offspring of mothers with a low level of education had an increased relative and absolute risk of asthma compared to offspring of high-educated mothers. ; All phases of this study were supported by a European Union's Seventh Framework Programme grant, 278350, as part of The Determinants to Reduce Health Inequity Via Early Childhood, Realising Fair Employment, and Social Protection (DRIVERS) research programme. The Czech ELSPAC Study (CZ-ELSPAC) was supported by the Ministry of Education of the Czech Republic: CETOCOEN plus project (CZ02101/00/00/15_003/0000469) and RECETOX Research Infrastructure (LM2015051). The Northern Finland Birth Cohort (FI-NFBC8586) received financial support from the Academy of Finland; Biocenter, University of Oulu, Finland; the European Commission EUROBLCS, Framework 5 Award QLG1-CT-2000-01643); EU FP7 EurHEALTHAgeing-277849; the Medical Research Council, UK (PrevMetSyn/SALVE); and the MRC Centenary Early Career Award. The Amsterdam Born Children and their Development Study (NLABCD) received funding from the Netherlands Organization for Health Research and Development (ZonMw) Grant (TOP, 40-00812-98-11010). The All Babies in Southeast Sweden Study (SE-ABIS) has received financial support from the Juvenile Diabetes Research Foundation, Swedish Child Diabetes Foundation (Barndiabetesfonden), The Research Council of South-east Sweden (FORSS), Swedish Research Council K2005-72X-11242-11A, and ALF/County Council of O ̈stergo ̈tland. The INMA study was funded in part by grants from the European Union (FP7-ENV-2011-282957 and HEALTH.2010.2.4.5-1), Spain (Instituto de Salud Carlos III and The Ministry of Health), the Conselleria de Sanitat of the Generalitat Valenciana, department of Health of the Basque Government, the Provincial Government of Gipuzkoa, and the Generalitat de Catalunya-CIRIT. Family and Children of Ukraine (UA-FCOU) study was supported by US NIH Fogarty International Center and National Academy of Medical Sciences of Ukraine. KML is funded by a Medical Research Council UK doctoral training studentship.