Socioeconomic disadvantage and health in early childhood: a population-based birth cohort study from Portugal

Background Measuring early socioeconomic inequalities in health provides evidence to understand the patterns of disease. Thus, our aim was to determine which children’s health outcomes are patterned by socioeconomics and to what extent the magnitude/direction of the differences vary by socioeconomic measure and outcome. Methods Data on early childhood (4 years) health was obtained from Generation XXI birth cohort (n = 8647). A total of 27 health outcomes and 13 socioeconomic indicators at the individual level and neighbourhood level were used to calculate the relative index of inequality (RII). Results Socioeconomic inequalities were evident across 21 of the 27 health outcomes. Education, occupation and income more often captured inequalities, compared with neighbourhood deprivation or employment status. Using highest maternal education as reference category, we observed that seizures (RII = 8.64), obesity (2.94), abdominal obesity (2.66), urinary tract infection (2.26), language/speech problems (2.24), hypertension (2.08) and insulin resistance (1.33) were heavily socially patterned, much more common in disadvantaged children. Contrastingly, eczema (0.26) and rhinitis (0.26) were more common among more advantaged children. Conclusions Socioeconomic inequalities were evident for almost every health outcome assessed, although with varying magnitude/direction according to the socioeconomic indicator and outcome. Our results reinforce that the social gradient in health manifests early in childhood.This study was funded by FEDER through the Operational Programme Competitiveness and Internationalization and national funding from the Foundation for Science and Technology – FCT (Portuguese Ministry of Science, Technology and Higher Education) under the Unidade de Investigação em Epidemiologia – Instituto de Saúde Pública da Universidade do Porto (EPIUnit) (POCI-01-0145-FEDER-006862; Ref. UID/DTP/04750/2019) and the project PTDC/GES-AMB/30193/2017 (POCI-01-0145-FEDER-030193, 02/SAICT/2017 - 30193) and ‘HIneC: When do health inequalities start? Understanding the impact of childhood social adversity on health trajectories from birth to early adolescence’ (POCI-01-0145-FEDER-029567; Reference: PTDC/SAU-PUB/29567/2017). G21 was funded by Programa Operacional de Saúde – Saúde XXI, Quadro Comunitário de Apoio III and Administração Regional de Saúde Norte (Regional Department of Ministry of Health). It also has support from the Portuguese Foundation for Science and Technology from the Calouste Gulbenkian Foundation. The research leading to these results has received funding from the European Community’s Horizon 2020 programme under grant agreement no. 633666 – the Lifepath project. S.F. was supported by the FCT Investigator contract CEECIND/01516/2017/CP1406/CT0001