CI, 1.11–4.12). Furthermore relative risks were significantly increased a) for children who were first births (OR = 1.66; 95% CI, 1.04–2.66) or high birth order after short birth interval (order ≥ 5 and < 24 months) (OR = 1.55; 95% CI, 1.01–2.36) compared with intermediate birth order and interval children; b) for children of mothers with no education (OR = 2.34; 95% CI, 1.31–3.16) or primary education (OR = 2.00; 95% CI, 1.27–3.13) compared with secondary or higher education; c) for children of moth- ers who were not working (OR = 2.56; 95% CI, 1.03–6.34) versus mothers in profes- sional, technical, or management jobs); and d) for children in the poorest versus wealthiest wealth quintile (OR = 1.64; 95% CI, 1.08– 2.57). The community-level variance was unchanged from model 2 and still significant (τ = 0.103, p = 0.043), indicating clustering of mothers of children with similar risk fac- tors within disadvantaged communities, and also implying a contextual effect that persisted after having accounted for relevant differences between disadvantaged neighborhoods in the characteristics of individual residents. The Table 2. Multilevel logistic regression models of urban area disadvantage and under-5 mortality [OR (95% CI)]. Model 0 (empty) Model 1 (UADI) 1 1.32 (1.19–1.54) 1.39 (1.26–1.56) 1.76 (0.52–1.81) 1.51 (0.65–1.72) Model 2 (child level) 1 1.32 (0.19–1.55) 1.38 (0.26–1.56) 1.76 (0.52–2.11) 1.49 (0.14–1.65) 1 1.04 (0.78–1.39) 1.40 (0.91–2.13) 1.05 (0.60–1.84) 1 0.76 (0.40–1.44) 2.17 (1.21–3.88) 1.16 (0.75–1.79) 0.76 (0.39–1.49) Characteristic Fixed effects UADI Class I (least disadvantaged) Class II Class III Class IV Class V (most disadvantaged) Child’s sex Male Female Child’s birth order, birth interval First birth (order 1) Order 2–4, < 24 months Order 2–4, 24–47 months Order 2–4, ≥ 48 months Order ≥ 5, < 24 months Order ≥ 5, 24–47 months Order ≥ 5, ≥ 48 months Mother’s marital status Single Married Divorced Mother’s age (years) 15–18 19–23 24–28 29–33 ≥ 34 Mother’s education No education Primary Secondary or higher Mother’s occupation Not working Clerical/sales/services/skilled manual Professional/technical/management Wealth index Poorest Poorer Middle Richer Richest Community level Variance (p-value) VPC Explained variation (PCV) (%) Mother level Variance (p-value) VPC Explained variation (PCV) (%) DIC 0.273 (0.111) 7.4 Reference 0.118 (0.334) 3.2 Reference 1,398 0.129 (0.063) 3.7 52.7 0.065 (0.107) 1.9 44.9 1,375 0.103 (0.043) 3.0 20.1 0.049 (0.091) 1.4 24.6 1,365 Data from Nigeria Demographic and Health Survey (2003). Environmental Health Perspectives • volume 118 | number 6 | June 2010 Model 3 (mother level) 1 1.72 (0.91–3.29) 1.78 (1.17–2.70) 2.03 (1.04–3.97) 2.14 (1.11–4.12) 1 1.02 (0.76–1.36) 1.66 (1.04–2.66) 1.07 (0.61–1.89) 1 0.65 (0.34–1.27) 1.55 (1.01–2.36) 0.81 (0.49–1.35) 0.51 (0.24–1.07) 0.67 (0.20–2.30) 1 1.57 (0.73–3.37) 0.84 (0.39–1.80) 0.81 (0.50–1.31) 1 1.08 (0.69–1.69) 1.53 (0.94–2.47) 2.34 (1.31–3.16) 2.00 (1.27–3.13) 1 2.56 (1.03–6.34) 1.53 (0.63–3.69) 1 1.64 (1.08–2.57) 1.60 (0.68–3.76) 1.50 (0.85–2.64) 1.01 (0.62–1.62) 1 0.097 (0.051) 2.8 6.8 0.032 (0.020) 0.9 34.7 1,287 Urban area disadvantage and under-5 mortality PCV of the odds of under-5 mortality was 6.8% and 34.7% across communities and mothers, respectively. However, we still found a fairly large amount of “unexplained” varia- tion among communities, which was prob- ably due to other unmeasured individual- and community-level factors. Lower DIC values with successive models indicated that our ana- lytic model was a good fit. Discussion Trend in urban under-5 mortality. We found that under-5 mortality rate increased with increasing urban population growth in Nigeria (urbanization) between the periods 1979–1983 and 1999–2003. On exami- nation of the association between under-5 mortality and UADI, our findings indicated that under-5 mortality rate increased with increasing levels of urban area disadvantage. Thus, the results of our study, in line with the results of other studies (Eloundou-Enyegue et al. 2000), suggest that with the increas- ing urban population and the resulting rapid urbanization within the context of poor eco- nomic circumstances in Nigeria, an increasing proportion of urban dwellers live in disadvan- taged urban neighborhoods with associated increased risks of under-5 deaths. Multilevel logistic regression modeling. This study provides evidence that the char- acteristics of urban areas have a significant association with the risks of under-5 deaths, above and beyond the mother’s SEP. Living in urban neighborhoods that are more socio- economically disadvantaged thus represents an independent mortality risk factor for chil- dren < 5 years of age, which confirms the findings from recent studies (Guidotti and Gitterman 2007; Pongou et al 2006). The increased risk of under-5 deaths among chil- dren living in these disadvantaged areas may be explained either directly as a result of living in a deprived neighborhood, as also reported in other studies (Dibben et al. 2006; Pickett and Pearl 2001), or indirectly as a sum of the socioeconomic characteristics of people liv- ing within these disadvantaged areas. Among such characteristics, we found that first birth was positively associated with under-5 death. Residing in a disadvantaged urban area may in itself be an important predictor of the sur- vival status of the first child. We found that mothers resident in highly disadvantaged areas were more likely to be younger and of low SEP (uneducated and in the poorest house- hold wealth quintile) than were other moth- ers. Lack of maternal experience in child care and lack of knowledge of health information may predispose first-born children of younger disadvantaged mothers to increased risks of morbidity and mortality (El-Zanaty and Way 2009). The survival of first births may also be associated with birth spacing and age of 881