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Household income and maternal education in early childhood and activity-limiting chronic health conditions in late childhood: findings from birth cohort studies from six countries
  1. Nicholas James Spencer1,
  2. Johnny Ludvigsson2,
  3. Yueyue You3,
  4. Kate Francis4,
  5. Yara Abu Awad5,
  6. Wolfgang Markham6,
  7. Tomas Faresjö7,
  8. Jeremy Goldhaber-Fiebert8,
  9. Pär Andersson White9,10,
  10. Hein Raat11,
  11. Fiona Mensah12,
  12. Lise Gauvin13,14,
  13. Jennifer J McGrath15
  14. EPOCH Collaborative Group
  1. 1Health Sciences, University of Warwick Warwick Medical School, Coventry, UK
  2. 2Department of Clinical and Experimental Medicine, Department of Psychology, Division of Pediatrics, Linköping University, S-581 85 Linköping, Sweden & Department of Behavioural Sciences and Learning, Linkoping, Sweden
  3. 3Public Health, Erasmus MC, Rotterdam, The Netherlands
  4. 4Population Health, Murdoch Children's Research Institute, Parkville, Victoria, Australia
  5. 5PERFORM Centre, Concordia University, Montreal, Québec, Canada
  6. 6Warwick Medical School, Warwick University, Coventry, UK
  7. 7Division of Community Medicine, Primary Care, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
  8. 8Centers for Health Policy and Primary Care and Outcomes Research, Stanford University, Stanford, California, USA
  9. 9Crown Princess Victoria Children's Hospital, Linköping, Sweden
  10. 10Department of Health, Medicine and Caring Science/Inst of Society and Health/Public Health, Linköping University, Linkoping, Sweden
  11. 11Public Health, Erasmus Medical Center, Rotterdam, The Netherlands
  12. 12Intergenerational Health, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
  13. 13Centre de Recherche, Centre Hospitalier de L'Universite de Montreal, Montreal, Québec, Canada
  14. 14Département de médecine sociale et préventive, Université de Montréal, Montréal, Québec, Canada
  15. 15Department of Psychology, Concordia University, Montreal, Québec, Canada
  1. Correspondence to Dr Nicholas James Spencer, Health Sciences, University of Warwick Warwick Medical School, Coventry, UK; n.j.spencer{at}warwick.ac.uk

Abstract

Background We examined absolute and relative relationships between household income and maternal education during early childhood (<5 years) with activity-limiting chronic health conditions (ALCHC) during later childhood in six longitudinal, prospective cohorts from high-income countries (UK, Australia, Canada, Sweden, Netherlands, USA).

Methods Relative inequality (risk ratios, RR) and absolute inequality (Slope Index of Inequality) were estimated for ALCHC during later childhood by maternal education categories and household income quintiles in early childhood. Estimates were adjusted for mother ethnicity, maternal age at birth, child sex and multiple births, and were pooled using meta-regression.

Results Pooled estimates, with over 42 000 children, demonstrated social gradients in ALCHC for high maternal education versus low (RR 1.54, 95% CI 1.28 to 1.85) and middle education (RR 1.24, 95% CI 1.11 to 1.38); as well as for high household income versus lowest (RR 1.90, 95% CI 1.66 to 2.18) and middle quintiles (RR 1.34, 95% CI 1.17 to 1.54). Absolute inequality showed decreasing ALCHC in all cohorts from low to high education (range: −2.85% Sweden, −13.36% Canada) and income (range: −1.8% Sweden, −19.35% Netherlands).

Conclusion We found graded relative risk of ALCHC during later childhood by maternal education and household income during early childhood in all cohorts. Absolute differences in ALCHC were consistently observed between the highest and lowest maternal education and household income levels across cohort populations. Our results support a potential role for generous, universal financial and childcare policies for families during early childhood in reducing the prevalence of activity limiting chronic conditions in later childhood.

  • child health
  • health inequalities
  • life course epidemiology
  • cohort studies

Data availability statement

Data are available on reasonable request. Data may be obtained from a third party and are not publicly available. Data underlying the results presented in this EPOCH study are available from the primary data sources. Data from the UK Millennium Cohort Study is available in a public open-access repository (https://cls.ucl.ac.uk/cls-studies/millennium-cohort-study/). Data from the Longitudinal Study of Australian Children (LSAC) is available in a public, open-access repository (https://growingupinaustralia.gov.au/data-and-documentation). Data from the US NLSY-79 is available in a public open-access repository (https://www.nlsinfo.org/content/cohorts/nlsy79-children). Data from the Rotterdam, Netherlands Generation R are available to request from (https://generationr.nl/researchers/); authors do not have permission to share their data. Data from Alla Barn I Sydöstra Sverige/All Babies in Southeast Sweden (ABIS) are available to request from (http://www.abis- studien.se); authors do not have permission to share their data.

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Data availability statement

Data are available on reasonable request. Data may be obtained from a third party and are not publicly available. Data underlying the results presented in this EPOCH study are available from the primary data sources. Data from the UK Millennium Cohort Study is available in a public open-access repository (https://cls.ucl.ac.uk/cls-studies/millennium-cohort-study/). Data from the Longitudinal Study of Australian Children (LSAC) is available in a public, open-access repository (https://growingupinaustralia.gov.au/data-and-documentation). Data from the US NLSY-79 is available in a public open-access repository (https://www.nlsinfo.org/content/cohorts/nlsy79-children). Data from the Rotterdam, Netherlands Generation R are available to request from (https://generationr.nl/researchers/); authors do not have permission to share their data. Data from Alla Barn I Sydöstra Sverige/All Babies in Southeast Sweden (ABIS) are available to request from (http://www.abis- studien.se); authors do not have permission to share their data.

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Footnotes

  • Contributors JJM, NJS and HR contributed to the concept and design of the EPOCH study. The concept and design of this paper was undertaken by NJS. YAA designed the statistical analysis and NJS and WM (MCS), YY (GenR), TF and PAW (ABIS), KF and FM (LSAC), YAA (NLSCY), JJM and JG-F (USNLSY) undertook data analysis for the respective cohorts. All authors contributed to the interpretation of data. NJS drafted and revised the manuscript assisted by comments and additions by all authors. All authors approved the final version. JJM is the guarantor of the paper.

  • Funding This study is based on a comparison of six international birth cohorts. EPOCH was partly supported by Canadian Institutes of Health Research (JJM: OCO-79897, MOP-89886, MSH- 95353; L. Séguin: ROG-110537). ABIS and this research were supported in part by the County Council of Ostergotland, Swedish Research Council (K2005-72X-11242-11A and K2008-69X-20826-01-4), the Swedish Child Diabetes Foundation (Barndiabetesfonden), Juvenile Diabetes Research Foundation, Wallenberg Foundation (K 98-99D-12813-01A), Medical Research Council of Southeast Sweden(FORSS), the Swedish Council for Working Life and Social Research (FAS2004–1775), and Ostgota Brandstodsbolag. Johnny Ludvigsson founded the ABIS Cohort. Longitudinal Study of Australian Children (LSAC) was initiated and funded by Australian Government Department of Social Services, with additional funding from partner organisations Australian Institute of Family Studies (AIFS) and Australian Bureau of Statistics (ABS). The study was conducted in partnership with the Department of Social Services (DSS), the Australian Institute of Family Studies (AIFS) and the Australian Bureau of Statistics (ABS). This paper uses unit record data from Growing Up in Australia, the Longitudinal Study of Australian Children. Generation R Study (GenR) was made possible by financial support from Erasmus Medical Center, Rotterdam; Erasmus University Rotterdam; Netherlands Organisation for Health Research and Development (ZonMw; additional grant received by V. Jaddoe, ZonMw 907.00303, 916.10159); Netherlands Organisation for Scientific Research (NWO); Ministry of Health, Welfare and Sport; and, Ministry of Youth and Families. Generation R Study (GenR) is conducted by Erasmus Medical Center in close collaboration with the School of Law and Faculty of Social Sciences of the Erasmus University Rotterdam, the Municipal Health Service Rotterdam area, Rotterdam, the Rotterdam Homecare Foundation, Rotterdam and the Stichting Trombosedienst & Artsenlaboratorium Rijnmond (STAR-MDC), Rotterdam. We gratefully acknowledge the contribution of children and parents, general practitioners, hospitals, midwives and pharmacies in Rotterdam. National Longitudinal Study of Children and Youth (NLSCY) was conducted by Statistics Canada and sponsored by Human Resources and Skills Development Canada (HRSDC); both agencies played a role in funding, development of survey content, research, and dissemination of findings. NLSCY and this research was supported by funds to the Canadian Research Data Centre Network (CRDCN) from the Social Sciences and Humanities Research Council (SSHRC), the Canadian Institute for Health Research (CIHR), the Canadian Foundation for Innovation (CFI), and Statistics Canada. Although the research and analysis are based on data from Statistics Canada, the opinions expressed do not represent the views of Statistics Canada. The UK Millennium Cohort Study (MCS) was supported by the Economic and Social Research Council, the Office of National Statistics, and various government departments. The study was led by the Centre for Longitudinal Studies at the Institute of Education of the University of London. We thank the Economic and Social Data Service and the United Kingdom Data Archive for permission to access the study data. The US National Longitudinal Survey of Youth (US-NLSY79) is sponsored and directed by U.S. Bureau of Labor Statistics and conducted by Center for Human Resource Research at The Ohio State University. Interviews are conducted by the National Opinion Research Center (NORC) at the University of Chicago. The Children of the NLSY79 survey is sponsored and directed by the US Bureau of Labor Statistics and the National Institute for Child Health and Human Development.

  • Disclaimer The findings and views reported in this paper are those of the authors and should not be attributed to the DSS, the AIFS or the ABS.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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