Being the younger child in a large African Family: A study of birth order as a risk factor for poor health using the demographic and health surveys for 18 countries

Background: One hundred eighty six nations have adopted 17 Sustainable Development Goals (SDGs), one of which, SDG 3.2, aims to reduce under-5 mortality to 25 deaths per thousand in all countries by 2030. Achieving this goal is daunting for many African countries, where child mortality remains high. Research around the world and over time has shown an association between birth order and mortality, with later born children (of higher "birth order") generally having higher mortality, in addition to having less education and fewer health services. We aim to investigate how child mortality and nutritional status vary by birth order in Africa. Methods: We obtained data from the Demographic and Health Surveys (DHS) from 18 African countries, one survey in each of the following decades: 1986-1995, 1996-2005, and 2006-2015. We examined mortality for two groups: ages 1-4 and 5-14, using a Cox proportional hazards model. We then examined 4 separate nutritional outcomes for young children using logistic regression. Nutritional outcomes are stunting, low weight, consuming fewer than 4 food groups in the past 24 h, and consuming any fruits or vegetables in that period. Analyses control for country and characteristics of the household, mother, and child. Results: Birth order is significantly related to mortality for both age groups. On average, there is a 13 % increase in mortality risk for each increase in birth order for children ages 1-4, and a 10 % increase in children ages 5-14. Similarly, we find that a higher birth order child is significantly more likely to be stunted (OR 1.08) or of low weight (OR 1.06). Higher birth order children are significantly more likely to consume fewer food groups (OR 1.11) and less often eat fruits and vegetables (OR 1.09). Conclusion: Birth order is significantly related to mortality and nutritional status in large African families, with later born children having poorer outcomes. These data suggest that increased attention to family planning initiatives and targeted nutritional interventions provide clear strategies for meeting the child mortality and nutritional status Sustainable Development Goals in African countries. © 2016 The Author(s).