Aurélie Nakamura1,2, Laura Pryor1,3, Morgane Ballon2,4, Sandrine Lioret4, Barbara Heude4, Marie-Aline Charles4, Maria Melchior1,5, Fabienne El-Khoury Lesueur1. 1. Sorbonne Université, INSERM, Institut Pierre Louis d'Épidémiologie et de Santé Publique (IPLESP), Paris, France. 2. French School of Public Health (EHESP), Doctoral Network, Rennes, France. 3. Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. 4. INSERM, UMR1153 Epidemiology and Biostatistics Sorbonne Paris Cité Center (CRESS), Early Origin of the Child's Health and Development Team (ORCHAD), Paris Descartes University, Paris, France. 5. Institut Convergences Migrations, Paris, France.
Abstract
BACKGROUND: Small for gestational age (SGA) birth weight, a risk factor for infant mortality and delayed child development, is associated with maternal educational attainment. Maternal tobacco smoking during pregnancy could contribute to this association. We aimed to quantify the contribution of maternal smoking during pregnancy to social inequalities in child birth weight for gestational age (GA). METHODS: Data come from the French nation-wide ELFE cohort study, which included 17 155 singletons. Birth weights for GA were calculated using z-scores. Associations between maternal educational attainment, tobacco smoking during pregnancy and child birth weight for GA were ascertained using mediation analysis. Mediation analyses were also stratified by maternal pre-pregnancy body mass index. RESULTS: Low maternal educational attainment was associated with an increased odd of tobacco smoking during pregnancy [adjusted OR (ORa) = 2.58 (95% CI 2.34-2.84)] as well as a decrease in child birth weight for GA [RRa = 0.94 (95% CI 0.91-0.98)]. Tobacco smoking during pregnancy was associated with a decrease in offspring birth weight for GA [RRa = 0.73 (95% CI 0.70-0.76)]. Mediation analysis suggests that 39% of the effect of low maternal educational attainment on offspring birth weight for GA was mediated by smoking during pregnancy. A more important direct effect of maternal educational attainment on child birth weight for GA was observed among underweight women [RRa = 0.82 (95% CI 0.72-0.93)]. CONCLUSIONS: The relationship between maternal educational attainment and child birth weight for GA is strongly mediated by smoking during pregnancy. Reducing maternal smoking could lessen the occurrence of infant SGA and decrease socioeconomic inequalities in birth weight for GA.
BACKGROUND: Small for gestational age (SGA) birth weight, a risk factor for infant mortality and delayed child development, is associated with maternal educational attainment. Maternal tobacco smoking during pregnancy could contribute to this association. We aimed to quantify the contribution of maternal smoking during pregnancy to social inequalities in child birth weight for gestational age (GA). METHODS: Data come from the French nation-wide ELFE cohort study, which included 17 155 singletons. Birth weights for GA were calculated using z-scores. Associations between maternal educational attainment, tobacco smoking during pregnancy and child birth weight for GA were ascertained using mediation analysis. Mediation analyses were also stratified by maternal pre-pregnancy body mass index. RESULTS: Low maternal educational attainment was associated with an increased odd of tobacco smoking during pregnancy [adjusted OR (ORa) = 2.58 (95% CI 2.34-2.84)] as well as a decrease in child birth weight for GA [RRa = 0.94 (95% CI 0.91-0.98)]. Tobacco smoking during pregnancy was associated with a decrease in offspring birth weight for GA [RRa = 0.73 (95% CI 0.70-0.76)]. Mediation analysis suggests that 39% of the effect of low maternal educational attainment on offspring birth weight for GA was mediated by smoking during pregnancy. A more important direct effect of maternal educational attainment on child birth weight for GA was observed among underweight women [RRa = 0.82 (95% CI 0.72-0.93)]. CONCLUSIONS: The relationship between maternal educational attainment and child birth weight for GA is strongly mediated by smoking during pregnancy. Reducing maternal smoking could lessen the occurrence of infant SGA and decrease socioeconomic inequalities in birth weight for GA.
Authors: Philip McHale; Gillian Maudsley; Andy Pennington; Daniela K Schlüter; Ben Barr; Shantini Paranjothy; David Taylor-Robinson Journal: BMC Public Health Date: 2022-06-07 Impact factor: 4.135