Research | Children’s Health Urban Area Disadvantage and Under-5 Mortality in Nigeria: The Effect of Rapid Urbanization Diddy Antai and Tahereh Moradi Division of Epidemiology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden Background : Living in socioeconomically disadvantaged areas is associated with increased childhood mortality risks. As city living becomes the predominant social context in low- and middle-income countries, the resulting rapid urbanization together with the poor economic cir- cumstances of these countries greatly increases the risks of mortality for children < 5 years of age (under-5 mortality). o Bjectiv : In this study we examined the trends in urban population growth and urban under-5 mortality between 1983 and 2003 in Nigeria. We assessed whether urban area socioeconomic dis- advantage has an impact on under-5 mortality. Methods : Urban under-5 mortality rates were directly estimated from the 1990, 1999, and 2003 Nigeria Demographic and Health Surveys. Multilevel logistic regression analysis was performed on data for 2,118 children nested within data for 1,350 mothers, who were in turn nested within data for 165 communities. r tluse : Urban under-5 mortality increased as urban population steadily increased between 1983 and 2003. Urban area disadvantage was significantly associated with under-5 mortality after adjust- ing for individual child- and mother-level demographic and socioeconomic characteristics. c onclusi : Significant relative risks of under-5 deaths at both individual and community levels underscore the need for interventions tailored toward community- and individual-level inter- ventions. We stress the need for further studies on community-level determinants of under-5 mor- tality in disadvantaged urban areas. k ey words : multilevel modeling, Nigeria, rapid urbanization, under-5 mortality, urban area disad- vantage, urban context. Environ Health Perspect 118:877–883 (2010). doi:10.1289/ehp.0901306 [Online 10 February 2010] Although it has long been known that there is a correlation between individual-level socio- economic position (SEP) and childhood mor- tality (Galobardes et al. 2006; Lawlor et al. 2006; Power et al. 2005), researchers have turned their attention to the role of socioeco- nomic characteristics of areas in child survival (Kawachi and Berkman 2003; Macintyre et al. 2002). The evidence suggests that liv- ing in socioeconomically disadvantaged areas is associated with increased mortality risks, even after adjusting for individual demo- graphic and socioeconomic characteristics (Bosma et al. 2001; Marinacci et al. 2004; Martikainen et al. 2003; Pickett and Pearl 2001; Sundquist et al. 1999). The world’s urban population is growing at a fast pace, necessitating greater emphasis on the asso- ciation between area-based measures of SEP within urban areas and the health of popula- tions living in those areas (Eames et al. 1993; Galea and Vlahov 2005). These area-based measures are seen largely as aggregate cor- relates of the individual measures and gen- erally show strong graded associations to most health outcomes. This not only mimics the associations seen at the individual level (Kaplan 1996) but also reflects the health effects of physical and social infrastructure above and beyond individual compositional effects (Kaplan 1996; Macintyre et al. 1993). Half of the world’s population (3 bil- lion people) now live in urban areas, and it is expected that by 2030 about two-thirds of the world’s population (5 billion people) will live in urban areas (United Nations Department of Economics and Social Affairs 2004). Urbanization, the process of becoming urban, reflects aggregate population growth in cities through either natural population increase or migration (Galea and Vlahov 2005) and is inextricably linked with devel- opment. As a result, urban or city living has become the ideal for many people in low- and middle-income countries (Kasarda and Crenshaw 1991). Urban living has impor- tant health benefits, such as better access to health care, education, and social amenities (McMichael 2002; Vlahov and Galea 2002). However, with the present pace of urbaniza- tion in low- and middle-income countries such as Nigeria and within the context of poor economic performance, poor gover- nance, failure of national and urban housing policies, and institutional and legal failure, the capacity of most urban economies in developing countries is overstretched. Hence, only a fraction of the growing social needs of urban areas are met (United Nations Human Settlements Programme 2003), resulting in an increasing proportion of urban dwellers living under disadvantaged conditions that are characterized by overcrowded or deterio- rating housing, inadequate social amenities, and poor environmental and sanitary condi- tions, as well as poor economic opportunities. Environmental Health Perspectives • volume 118 | number 6 | June 2010 This in turn increases the susceptibility of residents in these areas to a variety of health problems and increases childhood mortality risks (Alexander and Ehrlich 2000; Galea and Vlahov 2005; Gracey 2002; Hembree et al. 2005; Krieger and Higgins 2002; McMichael 2002; Northridge and Sclar 2003; Popkin 2001; Satterthwaite 2000; Vorster 2002; Zulu et al. 2002). Under such disadvantaged conditions, the health risks arising from living in disadvantaged urban areas rival or exceed those of rural areas, despite the generally eas- ier access of urban residents to modern health services (African Population and Health Research Center 2002; Timæus and Lush 1995), thereby outweighing the advantages of living in urban areas (Rakodi 1997). Why focus on urban area disadvantage? The importance of access to safe drinking water and housing structure quality, particularly in urban areas, is well documented. Diarrhea and other infectious diseases remain the major causes of death among children < 5 years of age (Bryce et al. 2005; Fotso et al. 2007; Woldemicael 2000). Availability of these resources is highly correlated with household SEP, which in turn is influenced by poverty and overall economic development in the community. Poor and disadvantaged urban populations are characterized by overcrowd- ing, shortage of safe water, lack of adequate waste and sanitary services, and higher levels of air pollution and other hazardous substances, which result in increased risks of infectious diseases and mortality (Mintz et al. 2001; Van de Poel et al. 2007). The SEP of people liv- ing in poor and disadvantaged urban com- munities is generally low and characterized by unemployment and underemployment (Ahmad et al. 2000). In addition, ownership of fewer assets and lack of access to economic resources among people living in poor and disadvantaged urban communities make them less able to cope with ill health (Adepoju 2004; Kandala et al. 2006; Wichmann and Voyi 2006). This is the urban neighborhood Address correspondence to D. Antai, Karolinska Institutet, Institute of Environmental Medicine, Division of Epidemiology, Nobels väg 13, 171 77 Stockholm, Sweden. Telephone: 46-8-52480015. Fax: 46-8-313961. E-mail: Diddy.Antai@ki.se We are grateful to Opinion Research Corporation Macro International, Inc. (ORC Macro Inc., Calverton, MD, USA) for the data used in this study. The authors declare they have no actual or potential competing financial interests. Received 7 August 2009; accepted 10 February 2010. 877