Skip to main content
Download PDF

Inequalities in child mortality in ten major African cities

BMC Medicine volume 12, Article number: 95 (2014) Cite this article

Abstract

Background

The existence of socio-economic inequalities in child mortality is well documented. African cities grow faster than cities in most other regions of the world; and inequalities in African cities are thought to be particularly large. Revealing health-related inequalities is essential in order for governments to be able to act against them. This study aimed to systematically compare inequalities in child mortality across 10 major African cities (Cairo, Lagos, Kinshasa, Luanda, Abidjan, Dar es Salaam, Nairobi, Dakar, Addis Ababa, Accra), and to investigate trends in such inequalities over time.

Methods

Data from two rounds of demographic and health surveys (DHS) were used for this study (if available): one from around the year 2000 and one from between 2007 and 2011. Child mortality rates within cities were calculated by population wealth quintiles. Inequality in child mortality was assessed by computing two measures of relative inequality (the rate ratio and the concentration index) and two measures of absolute inequality (the difference and the Erreyger’s index).

Results

Mean child mortality rates ranged from about 39 deaths per 1,000 live births in Cairo (2008) to about 107 deaths per 1,000 live births in Dar es Salaam (2010). Significant inequalities were found in Kinshasa, Luanda, Abidjan, and Addis Ababa in the most recent survey. The difference between the poorest quintile and the richest quintile was as much as 108 deaths per 1,000 live births (95% confidence interval 55 to 166) in Abidjan in 2011–2012. When comparing inequalities across cities or over time, confidence intervals of all measures almost always overlap. Nevertheless, inequalities appear to have increased in Abidjan, while they appear to have decreased in Cairo, Lagos, Dar es Salaam, Nairobi and Dakar.

Conclusions

Considerable inequalities exist in almost all cities but the level of inequalities and their development over time appear to differ across cities. This implies that inequalities are amenable to policy interventions and that it is worth investigating why inequalities are higher in one city than in another. However, larger samples are needed in order to improve the certainty of our results. Currently available data samples from DHS are too small to reliably quantify the level of inequalities within cities.

Peer Review reports

Background

The existence of health-related inequalities across different areas as well as across different socio-economic groups is well documented [1–5]. Numerous studies have demonstrated that urban areas have lower infant and child mortality rates than rural areas [3, 4, 6–9]; and there is even more extensive literature showing that mortality is much lower among higher socio-economic groups than among the poor [2, 10–14].

African cities are growing faster than cities in most other regions of the world [15], and by 2020 more people are estimated to be living in African cities than in European cities. In 2010, almost 40% of Africans lived in urban areas, with about 33% of urban Africans living in cities of more than 1 million inhabitants [15]. Living conditions in Sub-Saharan African cities remain particularly poor, and more than 60% of city dwellers live in slums [16], meaning that they lack either durable housing, sufficient space, access to safe water or basic sanitation. In addition, economic inequality as measured by the Gini-coefficient is higher in African cities than in most other cities of the world [17]. In Northern African cities, living conditions are better with about 13% of the urban population living in slums [16].

In 2010, child (under-five years old) mortality in Africa was estimated to be at 111 per 1,000 live births [18]. On average 132 children died per 1,000 live births in rural areas compared to 102 in urban areas (based on data from 28 African countries with recent (2005 to 2011) data from demographic and health surveys (DHS)) [19]. However, while child mortality is on average lower in urban areas, a previous study and a World Health Organization (WHO) report have highlighted that child mortality of the poor is often higher in urban than in rural areas [20, 21]; this is explained by the fact that inequalities between rich and poor tend to be larger in cities than in rural areas.

Inequalities in child mortality are generally considered to constitute inequities because they are perceived to be unfair, socially produced and potentially modifiable [22]. A 2010 joint WHO and United Nations Human Settlements Programme (UN-HABITAT) report [21] urged countries to disaggregate data within cities in order to unmask health-related inequities. However, available studies of urban inequalities in child mortality usually look at all urban residents within a country [7, 9, 20, 23]. Only very few studies are available that investigate inequalities within specific African cities [24–26], and systematic information comparing the magnitude of inequalities in child mortality across different cities and the development of inequalities over time is unavailable. Yet, unless inequalities are investigated and revealed, it is impossible for governments to act against them [21].

This study aimed to systematically compare inequalities in child mortality across 10 major African cities and to investigate the development of inequalities over time (the last decade or so, depending on the availability of data). More specifically, the objectives were: (1) to calculate child mortality rates by wealth quintiles within cities; (2) to quantify the degree of inequality within cities using different established measures of inequality [27, 28]; (3) to determine whether child mortality is more unequally distributed in some cities than in others; and (4) to assess whether certain cities have succeeded in reducing inequalities over time.

Methods

Data availability and city sample

Data for this study were drawn from DHS and one malaria indicator survey (MIS) (see Table 1). These surveys are generally carried out by national statistical offices with support provided by Measure DHS, a project that helps developing countries collect data on health and population trends [29]. Surveys and datasets are highly standardized and inconsistencies in responses are reduced during data processing [30]. Among many other things, each included survey contains information on the complete birth histories of interviewed women (15- to 49- years old), that is, information on dates of all births and deaths of their children, and an indicator of household living standards in the form of a wealth index [31].

Table 1 Population size of cities included in the sample and characteristics of surveys available for these cities
Full size table

The 10 largest cities in Africa according to data from the UN World Urbanization Prospects (2011 Revision) [15] were included in the city sample if they fulfilled the following two criteria: (1) they were the largest city in their country (that is, only one city per country was included); and (2) there was at least one DHS conducted after 2005. DHS data were downloaded from the Measure DHS website [32]. In addition, for each city, data from one survey that was closest to the year 2000 and that contained a wealth index variable was also included in the data sample in order to enable trend comparisons.

Table 1 summarizes information about the selected sample of cities and the available data. Cities included in the sample had between 2.5 million (Accra) and 11.0 million (Cairo) inhabitants in 2010, and almost always accounted for a sizeable part of the total population in their respective countries, that is, between 3% (Addis Ababa) and 25% (Luanda). For eight cities, data are available from a survey conducted around the year 2000 (between 1997 and 2003). Four of these surveys contain full birth histories on more than 1,000 births having occurred in the 10 years prior to the interview, while the other four surveys have a much smaller sample size (less than 500 births). The number of deaths of children under-five years of age that occurred in the samples ranges from 18 in Accra to 112 in Abidjan. The more recent surveys were conducted between 2007 (Kinshasa) and 2011–2012 (Abidjan). Most of these later surveys include full birth histories of more than 1,000 children and only two surveys contain fewer than 500 children. The number of included under-five deaths ranges from 16 in Accra to 181 in Luanda.

Calculation of child mortality by wealth quintile

Household living standards are measured in DHS surveys using information on, among others, ownership of selected assets (for example, bicycle, phone), availability of basic services (for example, water supply, electricity) and household flooring material [31]. This information is aggregated into a household wealth index score, which places households on a continuous scale of relative wealth, using principal component analysis. For this study, the wealth index score available in DHS data sets was used to create city-specific wealth quintiles of births, by ordering all included births (those having occurred in the city in the previous 10 years) according to their wealth index score and dividing the distribution at the cut-off points of each 20 percent section. Sample weights were not used in the analyses because households within cities had the same probability of being selected into the DHS samples. (Please see Additional file 1: Box S1 in the supplementary online material for a justification.)

Child (under-five years old) mortality rates were calculated separately for each wealth quintile using a synthetic cohort life table approach as is standard practice for DHS analyses [29]. The synthetic cohort life table method combines mortality probabilities for small age segments, for which real cohort mortality can be calculated, into total child mortality using a life table approach. Following DHS methodology [29], mortality probabilities were calculated for eight age segments (0, 1 to 2, 3 to 5, 6 to 11, 12 to 23, 24 to 35, 36 to 47, 48 to 59 months), and the total child mortality rate was calculated as the cumulative probability of having died at the end of the last age segment. Calculations were performed in SPSS Version 15. Ninety-five percent confidence intervals around child mortality rates were calculated from standard errors of the cumulative probability of dying.

Assessment of inequalities

Inequality across wealth quintiles was visualized by drawing concentration curves [33–35]. The child mortality concentration curve plots the cumulative proportion of deaths (on the y-axis) against the cumulative percentage of children at risk ranked by wealth quintile (on the x-axis), beginning with the poorest and ending with the richest [34]. If all children, irrespective of the wealth status of their household, had exactly the same mortality rates, the concentration curve would be a 45-degree line, running from the bottom left-hand corner to the top right-hand corner. If more children die in the poorer quintiles than in the richer quintiles, the concentration curve lies above this line of equality.

In order to assess the level and development of inequalities across cities, two simple and two more complex measures of inequality were calculated [27]: the difference, the ratio, the concentration index and the Erreygers index [28, 36]. The difference in child mortality rates between the richest and the poorest quintiles was calculated because it is the most straightforward measure of absolute inequality, and the ratio of the child mortality rate in the poorest divided by the rate in the richest quintile because it is the simplest relative measure of inequality [27]. Confidence intervals for the rate difference and the rate ratio were calculated according to methods described by Moser et al. [14].

The concentration index was calculated to quantify the magnitude of relative inequality across all wealth quintiles [27, 35]. The concentration index is defined as twice the area between the concentration curve and the line of equality [33, 34, 37] and has become the standard tool in health economics for evaluating socioeconomic inequalities [36]. In addition, because the value of the concentration index is affected by the average level of child mortality in a city [38], a normalized version of the concentration index, that is, the Erreygers index was calculated [39]. While the concentration index (being a relative measure of inequality) would indicate that the same absolute difference in child mortality between the rich and poor is more severe when child mortality is low, the Erreygers index would show no change in inequality if child mortality of all wealth quintiles was increased (or reduced) by the same absolute amount [36]. Furthemore, the Erreygers index has the advantage that the level of measured inequality would be the same, independent of whether child mortality or child survival was measured [28, 39]. Confidence intervals around concentration indices and Erreygers indices were calculated according to methods described by Kakwani et al. [35, 37].

Results

Child mortality by wealth quintiles across cities

Figure 1a shows mean child (under-five years old) mortality rates and rates by wealth quintiles across the ten cities included in the more recent round of surveys. Mean child mortality rates range from about 39 deaths per 1,000 live births in Cairo (2008) to about 107 deaths per 1,000 live births in Dar es Salaam (2010). Because of relatively small sample sizes, point estimates of child mortality rates by wealth quintiles are associated with considerable uncertainty as indicated by large 95% confidence intervals. However, except for Dar es Salaam, where the sample size is particularly small, the richest quintiles always have the lowest child mortality rates, while poorer quintiles have considerably higher rates. In addition, it is clear that the size of the difference between rich and poor and the pattern of the distribution of child mortality rates across quintiles vary across cities, even when considering the large degree of uncertainty.Figure 1b shows child mortality rates calculated from the earlier surveys. Mean child mortality rates in most cities were even higher at the time of the earlier surveys. The degree of uncertainty around point estimates in several cities is even larger than in the later surveys. Nevertheless, the difference between rich and poor appears to have been even greater in these surveys.

Figure 1
figure 1

Under-five mortality rates by wealth quintiles for 10 African cities, development over time. a: Mean under-five mortality rates (diamonds) and rates by wealth quintiles (with 95% confidence intervals) in ten African cities, more recent surveys. Notes: Quintile 1 = poorest; quintile 5 = richest; * sample size <1,000 children; ** sample size <500 children. b: Mean under-five mortality rates (diamonds) and rates by wealth quintiles (with 95% confidence intervals) in eight African cities, earlier surveys. Notes: Quintile 1 = poorest; quintile 5 = richest; ** sample size <500 children.

Full size image

Development of inequalities within cities over time

Figure 2 illustrates relative inequalities across the ten included cities by means of concentration curves. For almost all surveys and all cities (with the exception of one survey each in Dar es Salaam and Accra), concentration curves always lie almost entirely above the lines of equality, indicating that mortality is higher in lower wealth quintiles than in higher wealth quintiles. In Dar es Salaam and Accra, concentration curves have an odd shape, which is likely to be related to the very low sample sizes in these cities.

Figure 2
figure 2

Concentration curves for 10 African cities, development over time. Notes: * sample size <1000; ** sample size <500. A concentration curve above the line of equality indicates that child mortality is higher amongst the poor than amongst the rich. The level of inequality is higher if the distance between the concentration curve and the line of equality is greater.

Full size image

For eight out of the ten included cities, two surveys were available to assess trends in the development of inequalities over time. In most cities, that is, Cairo, Lagos, Dar es Salaam, Nairobi and Dakar, inequalities appear to have decreased over time as concentration curves from more recent surveys lie closer to the lines of equality. In Abidjan, inequality appears to have increased as the concentration curve for 2011–2012 is farther away from the line of equality than the concentration curve for 1998–1999. In Addis Ababa and Accra, the concentration curves from earlier and later years cross, making it more difficult to determine whether inequalities increased or decreased over time.

Comparison of inequality across cities and over time

Table 2 compares inequalities in child mortality rates across cities and over time using four measures of inequality: the difference between poor and rich, the ratio, the concentration index and the Erreygers index. In the earlier round of surveys, all four measures exhibit significant inequalities across all cities except Accra as 95% confidence intervals do not include zero (or one in the case of the ratio). However, when comparing inequalities across cities, confidence intervals (CI) of all measures almost always overlap. Notable exceptions include Cairo, where the difference in child mortality rates between rich and poor was 40 deaths (CI 6 to 75) per 1,000 childbirths in 2000, when compared with Dar es Salaam, where the difference was 196 deaths (CI 83 to 310) per 1,000 childbirths in 1999, and Abidjan, where both the concentration index and the Erreygers index are significantly smaller than these measures in Dar es Salaam. In addition, absolute inequality as measured by the Erreygers index is significantly lower in Cairo than in Dar es Salaam and Addis Ababa because the absolute difference between rich and poor in Cairo is relatively small. By contrast, the level of relative inequality as measured by the concentration index is not significantly different in Cairo because in relative terms richer children still die much more frequently than poor children.

Table 2 Comparison of the level of inequalities in child mortality and trends over time across ten African cities
Full size table

In the most recent surveys, significant inequalities exist in Kinshasa, Luanda, Abidjan, and Addis Ababa, where confidence intervals of all four inequality measures do not include zero (or one in the case of the ratio). In Accra, the concentration index and the Erreyger’s index also indicate significant inequalities. By contrast, when compared with the earlier surveys, measured inequality has reduced considerably in Cairo, Lagos, Dar es Salaam, Nairobi, and Dakar. In fact, inequality has become insignificant in these cities as confidence intervals now include zero (or one). For Dar es Salaam, the difference between the earlier and later surveys appears to be significant as confidence intervals of most measures do not overlap. By contrast, inequality seems to have increased in Abidjan and Accra although confidence intervals of earlier and later surveys overlap. In Addis Ababa, absolute inequality appears to have reduced while relative inequality remained more or less unchanged.

Discussion

This is the first study to systematically investigate socio-economic inequalities in child mortality within and across African cities and their development over time. We disaggregated data from two rounds of demographic and health surveys and calculated four measures of socio-economic inequality for ten cities in Africa. The results show that in most cities, child mortality is considerably higher among the poor than among the rich, with the difference between the poorest quintile and the richest quintile reaching as much as 108 deaths per 1,000 live births in Abidjan in 2011–2012. Around the year 2000, Dar es Salaam had the highest level of inequality, while Abidjan and Cairo had rather low absolute (Cairo) and relative (Abidjan) inequality. Since then, inequality appears to have reduced in about half of the included cities (Cairo, Lagos, Dar es Salaam, Nairobi and Dakar), while it appears to have increased in Abidjan. However, given the high degree of uncertainty surrounding the point estimates of child mortality (see Figure 1) and the resulting uncertainty around our measures of inequality (Table 2), results need to be interpreted with caution.

The study has a number of limitations. The most important one is the limited sample size of DHS within cities, which are not intended to be used for within-city analyses. In the earlier round of surveys, only four cities had data available from more than 1,000 children, and also in the later round, the samples of three cities were smaller than 1,000 children (see Table 1). Consequently, reliability of child mortality estimates is questionable and large confidence intervals around point estimates complicate the interpretation of results (see Table 2). Nevertheless, DHS remain the most reliable source of information currently available in most African countries, and they are used regularly by international agencies for estimating child mortality [40]. Civil registration and vital statistics systems (CRVS) – if available at all – usually record only a small fraction of all births and deaths [41], and child mortality data from censuses is often questionable. For example, in Abidjan, it is estimated that only about 70% of births and less than 40% of deaths (and even fewer among children) are registered by the CRVS [42], and child mortality was grossly underreported in the last Ivorian census conducted in 1998 [43]. DHS usually report child mortality figures for children born in the five years preceding the survey [29]. Our study included birth histories and deaths of children born in the ten years preceding the survey in order to increase the sample size. This means that recent changes in inequality are only marginally reflected in our estimates, and they are not directly comparable with the figures reported in DHS. Furthermore, because birth histories cover the previous ten years, some of the included births and deaths may, in fact, have occurred before households moved to cities.

A second limitation of our study related to the use of DHS data is that the DHS wealth index combines information about household ownership of selected assets with the availability of basic community-level services, such as water or electricity [31]. This can be problematic because it can lead to the misclassification of relatively rich households into the group of relatively poor households if they live in relatively poor neighborhoods [44, 45]. The problem is thought to be particularly relevant when comparing urban areas, where more community-level services are available, with rural areas. However, in our study of major cities, where residential patterns tend to be more segregated, the misclassification of households is likely to be less of a problem, although it may still lead to an underestimation of the true extent of inequality.

A third limitation of this study concerns the comparison of inequality across cities and the assessment of trends over time. One problem is that DHS data from different cities were not available for the same years. For example, the most recent survey from Cairo was from 2008, while the most recent survey from Luanda was from 2011. Consequently, inequality is compared across cities at different points in time, and depending on the trend over time differences in inequality across cities might have reduced or increased beyond what can be seen in the data. In addition, the time period between the first and the second survey ranged from five years in Lagos to almost fourteen years in Abidjan and Dakar, and consequently, the change in inequality from the first survey to the later survey, which is shown in Figure 2 and Table 2, might appear relatively smaller in cities with a shorter time period between surveys than in those with longer periods. Another problem is that we selected only four measures of inequality to compare cities and to assess the trend in inequalities over time. A host of further measures are available [27, 28, 33], including odds ratios, the slope index of inequality, the relative index of inequality, the generalized concentration index, and the Wagstaff index. In addition, it has been shown that measured inequality may differ depending on the chosen indicator [12, 14, 36]. However, our selection of two measures of relative inequality (the rate ratio and the concentration index) and two measures of absolute inequality (the difference and the Erreygers index) is similar to other studies [5] and should provide a reasonably nuanced view of the development of inequalities across cities.

Finally, a major weakness of our study is that it did not investigate the underlying reasons for the identified differences in inequalities across cities and for the differences in trends over time. Prior studies have decomposed calculated concentration indices in order to assess the contribution of different factors to inequality in infant [46] or child [47–49] mortality. However, the small size of the samples from the 10 African cities included in our study would draw into question the value of such analyses. Further research is needed to improve data availability from cities and to investigate reasons for differences in inequality and differences in trends over time.

Despite these limitations, our research has important implications for policy-makers and researchers. In 2010, a joint WHO and UN-HABITAT report [21] urged countries to unmask health-related inequities in cities. Our study is the first to do this and to show the high level of inequalities in child mortality that exists within African cities. However, both average child mortality in the included cities and mortality of the poorest quintile are generally considerably below the corresponding national figures (see Additional file 1: Table S1 in the supplementary online material for national child mortality rates by wealth quintile). A previous study [20] found that in nine low income countries, child mortality was significantly higher among the urban poor than among the rural poor. Our sample included no cities from these nine countries but our results seem to suggest that child mortality is lower in major African cities than in the rest of the country (see Additional file 1: Table S1), not only on average but also among the poor. This is in line with findings of another recent study [9], which found that child mortality rates of children living in households in urban slums are higher than the rates of those living in formal settlements – but still lower than child mortality rates in rural areas.

In addition, our study reveals that the level of inequality in child mortality differs across cities and over time. Inequality in Abidjan was relatively low in 1998–1999, when compared with other African cities, but it was rather high in 2011–2012. Inequality in Cairo, Lagos, Dar es Salaam, Nairobi and Dakar seems to have reduced over (more or less) the same period of time. One explanation for these opposing trends might be that Abidjan suffered considerably during the time of political instability and civil war in Côte d’Ivoire, which lasted from 1999 to 2011 [50]. Armed conflict has been shown to contribute significantly to increased child mortality not only during but also after the period of active warfare [51–53]. Conflict is likely to disproportionately affect the poor [54], and consequently inequities seem to be particularly severe in countries with a history of recent conflict [55]. Another possible explanation might be that inequality of wealth decreased in some cities, and that this drove a decrease in inequality of child mortality. A decrease in inequality of mean wealth scores by income quintiles in Dar es Salaam, Lagos and Nairobi – cities where inequality seems to have decreased over time – might support this hypothesis, although there is no clear correlation, when looking at all included cities (see Additional file 1: Table S2). Child mortality is, of course, affected also by more proximate factors, including lack of shelter, sufficient nutrition or access to clean water and sanitation, as well as inadequate public health expenditures, low female education and short birth intervals [56–58], and inequality in child mortality is largely related to unequal distribution of these factors [46, 48, 49]. Also, Kinshasa, Luanda, Addis Ababa and Accra were found to have significant levels of inequality in the more recent round of surveys, and these cities may benefit from looking at cities that achieved reductions in inequality over time.

Finally, our study shows that larger sample sizes are needed in order to more reliably assess inequalities in child mortality within and across cities and in their development over time. Luanda was the only city included in this study with a DHS that contained full birth histories for more than 2,000 children (Table 1). WHO and UNHABITAT have asked countries to disaggregate available data in order to reveal health-related inequalities within cities [21]. However, the small sample sizes of DHS mean that there is considerable uncertainty when this data is disaggregated in order to assess inequalities within cities. The need to improve data availability in developing countries has been recognized by the most important players in global health [59]. Ultimately, civil registration and vital statistics systems will need to be strengthened. However, in the short-term coverage of health and demographic surveillance systems, which collect demographic and health data for a population living in a well-defined geographic area, could be improved in cities, whereas they are currently mostly focused on rural areas [60, 61].

Conclusions

The need to investigate health-related inequalities within cities is increasingly being recognized by international agencies [16, 21] as this is a prerequisite for national governments to act against them. Our study shows that considerable inequalities in child mortality exist in almost all cities but that the level of inequalities and their development over time differ across cities. This implies that inequalities are amenable to policy interventions and that it is worth investigating why inequalities are higher in one city than in another. However, the size of the data samples available from our cities is relatively small, leading to considerable uncertainty concerning the rate of child mortality in different population groups (poor versus rich) and this complicates interpretation of our results. Larger sample sizes are needed in order to improve the certainty of our results, to reliably quantify the level of inequalities within cities and to identify factors that can help to reduce inequalities over time.

References

  1. Gwatkin DR: Health inequalities and the health of the poor: what do we know? What can we do?. Bull World Health Organ. 2000, 78: 3-18.

    CAS  PubMed  PubMed Central  Google Scholar 

  2. Victora CG, Wagstaff A, Schellenberg JA, Gwatkin D, Claeson M, Habicht J: Applying an equity lens to child health and mortality: more of the same is not enough. Lancet. 2003, 362: 233-241. 10.1016/S0140-6736(03)13917-7.

    Article  PubMed  Google Scholar 

  3. Wang L: Determinants of child mortality in LDCs. Health Policy. 2003, 65: 277-299. 10.1016/S0168-8510(03)00039-3.

    Article  PubMed  Google Scholar 

  4. Sahn DE, Stifel DC: Urban–rural inequality in living standards in Africa. J Afr Econ. 2003, 12: 564-597. 10.1093/jae/12.4.564.

    Article  Google Scholar 

  5. Barros AJ, Ronsmans C, Axelson H, Loaiza E, Bertoldi AD, França GV, Bryce J, Boerma JT, Victora CG: Equity in maternal, newborn, and child health interventions in Countdown to 2015: a retrospective review of survey data from 54 countries. Lancet. 2012, 379: 1225-1233. 10.1016/S0140-6736(12)60113-5.

    Article  PubMed  Google Scholar 

  6. Le R, Booysen F: Urban–rural inequalities in health care delivery in South Africa. Dev Southern Afr. 2003, 20: 659-673. 10.1080/0376835032000149298.

    Article  Google Scholar 

  7. van de Poel E, O’Donnell O, van Doorslaer E: What explains the rural–urban gap in infant mortality: household or community characteristics?. Demography. 2009, 46: 827-850. 10.1353/dem.0.0074.

    Article  PubMed  PubMed Central  Google Scholar 

  8. Anyamele OD: Urban and rural differences across countries in child mortality in sub-Saharan Africa. J Health Care Poor Underserved. 2009, 20: 90-98. 10.1353/hpu.0.0199.

    Article  PubMed  Google Scholar 

  9. Günther I, Harttgen K: Deadly cities? spatial inequalities in mortality in sub-Saharan Africa. Popul Dev Rev. 2012, 38: 469-486. 10.1111/j.1728-4457.2012.00512.x.

    Article  Google Scholar 

  10. Adler NE, Ostrove JM: Socioeconomic status and health: what we know and what we don’t. Ann N Y Acad Sci. 1999, 896: 3-15. 10.1111/j.1749-6632.1999.tb08101.x.

    Article  CAS  PubMed  Google Scholar 

  11. Minujin A, Delamonica E: Mind the gap! Widening child mortality disparities. J Hum Dev. 2003, 4: 397-418. 10.1080/1464988032000125764.

    Article  Google Scholar 

  12. Houweling TA, Kunst AE, Huisman M, Mackenbach JP: Using relative and absolute measures for monitoring health inequalities: experiences from cross-national analyses on maternal and child health. Int J Equity Health. 2007, 6: 15-10.1186/1475-9276-6-15.

    Article  PubMed  PubMed Central  Google Scholar 

  13. Houweling TAJ, Kunst AE: Socio-economic inequalities in childhood mortality in low- and middle-income countries: a review of the international evidence. Br Med Bull. 2010, 93: 7-26. 10.1093/bmb/ldp048.

    Article  PubMed  Google Scholar 

  14. Moser K, Frost C, Leon DA: Comparing health inequalities across time and place - rate ratios and rate differences lead to different conclusions: analysis of cross-sectional data from 22 countries 1991 2001. Int J Epidemiol. 2007, 36: 1285-1291. 10.1093/ije/dym176.

    Article  PubMed  Google Scholar 

  15. United Nations: World Urbanization Prospects: The 2011 Revision. 2012, New York: United Nations, Department of Economic and Social Affairs, Population Division

    Google Scholar 

  16. UN-HABITAT: State of the World’s Cities 2010/2011: Bridging the Urban Divide. 2010, London, Washington, DC: Earthscan

    Google Scholar 

  17. UN-HABITAT: State of the World’s Cities, 2012/2013: Prosperity of Cities. 2013, New York: Routledge for and on behalf of UN-Habitat

    Google Scholar 

  18. UNICEF: The State of the World’s Children 2012: Children in an Urban World. 2012, New York

    Google Scholar 

  19. World Health Organization: Global Health Observatory Data Repoistory: Health Equity Monitor. 2014, Geneva

    Google Scholar 

  20. van de Poel E, O’Donnell O, van Doorslaer E: Are urban children really healthier? Evidence from 47 developing countries. Soc Sci Med. 2007, 65: 1986-2003. 10.1016/j.socscimed.2007.06.032.

    Article  PubMed  Google Scholar 

  21. World Health Organization, UN Habitat: Hidden Cities: Unmasking and Overcoming Health Inequities in Urban Settings. 2010, New York: United Nations Development Programme

    Google Scholar 

  22. Stephens C: Urban inequities; urban rights: a conceptual analysis and review of impacts on children, and policies to address them. J Urban Health. 2012, 89: 464-485. 10.1007/s11524-011-9655-5.

    Article  PubMed  PubMed Central  Google Scholar 

  23. Fotso J: Child health inequities in developing countries: differences across urban and rural areas. Int J Equity Health. 2006, 5: 9-10.1186/1475-9276-5-9.

    Article  PubMed  PubMed Central  Google Scholar 

  24. African Population and Health Research Center: Urban Health in Kenya: Key Findings: The 2000 Nairobi Cross-Sectional Slum Survey. 2012, Nairobi

    Google Scholar 

  25. Magadi M: Maternal and child health among the urban poor in Nairobi, Kenya. Afr Popul Stud. 2004, 19: 171-190.

    Google Scholar 

  26. Fobil JN, Levers C, Lakes T, Loag W, Kraemer A, May J: Mapping urban malaria and diarrhea mortality in Accra, Ghana: evidence of vulnerabilities and implications for urban health policy. J Urban Health. 2012, 89: 977-991. 10.1007/s11524-012-9702-x.

    Article  PubMed  PubMed Central  Google Scholar 

  27. World Health Organization: Handbook on Health Inequality Monitoring: With a Special Focus on Low- and Middle-Income Countries. 2013, Geneva

    Google Scholar 

  28. Erreygers G, van Ourti T: Measuring socioeconomic inequality in health, health care and health financing by means of rank-dependent indices: a recipe for good practice. J Health Econ. 2011, 30: 685-694. 10.1016/j.jhealeco.2011.04.004.

    Article  PubMed  PubMed Central  Google Scholar 

  29. Rutstein SO, Rojas G: Guide to DHS Statistics: Demographic and Health Surveys Methodology. 2006, Calverton, MD: Macro International

    Google Scholar 

  30. Measure DHS: Demographic and Health Survey Sampling and Household Listing Manual. 2012, Calverton, MD: Macro International

    Google Scholar 

  31. Rutstein SO, Johnson K: The DHS Wealth Index. DHS Comparative Reports No. 6. 2004, Calverton, Maryland: ORC Macro

    Google Scholar 

  32. Demographic and Health Survey (DHS) database. http://dhsprogram.com/Data/.

  33. Wagstaff A, Paci P, van Doorslaer E: On the measurement of inequalities in health. Soc Sci Med. 1991, 33: 545-557. 10.1016/0277-9536(91)90212-U.

    Article  CAS  PubMed  Google Scholar 

  34. Wagstaff A: Socioeconomic inequalities in child mortality: comparisons across nine developing countries. Bull World Health Organ. 2000, 78: 19-29.

    CAS  PubMed  PubMed Central  Google Scholar 

  35. O’Donnell O, van Doorslaer E, Wagstaff A, Lindelow M: Analyzing Health Equity Using Household Survey Data. 2007, World Bank Publications

    Book  Google Scholar 

  36. Kjellsson G, Gerdtham U: On correcting the concentration index for binary variables. J Health Econ. 2013, 32: 659-670. 10.1016/j.jhealeco.2012.10.012.

    Article  PubMed  Google Scholar 

  37. Kakwani N, Wagstaff A, van Doorslaer E: Socioeconomic inequalities in health: measurement, computation, and statistical inference. J Econ. 1997, 77: 87-103. 10.1016/S0304-4076(96)01807-6.

    Article  Google Scholar 

  38. Wagstaff A: The bounds of the concentration index when the variable of interest is binary, with an application to immunization inequality. Health Econ. 2005, 14: 429-432. 10.1002/hec.953.

    Article  PubMed  Google Scholar 

  39. Erreygers G: Correcting the concentration index. J Health Econ. 2009, 28: 504-515. 10.1016/j.jhealeco.2008.02.003.

    Article  PubMed  Google Scholar 

  40. Hill K, You D, Inoue M, Oestergaard MZ, Byass P: Child mortality estimation: accelerated progress in reducing global child mortality, 1990–2010. PLoS Med. 2012, 9: e1001303-10.1371/journal.pmed.1001303.

    Article  PubMed  PubMed Central  Google Scholar 

  41. World Health Organization-Regional 0ffice for Africa: Atlas of African Health Statistics 2012. 2012, Brazzaville

    Google Scholar 

  42. Bakayoko M: Rapport de collecte et d’analyse des statistiques de l’état civil de la ville d’Abidjan. 2007, Abidjan: Institut National de la Statistique

    Google Scholar 

  43. Onéné D: Recensement général de la population et de l’habitation de 1998: Rapport d’analyse thème 4: La mortalité. 2001, Abidjan: Institut National de la Statistique

    Google Scholar 

  44. Gordon D, Nandy S: Measuring Child Poverty and Deprivation. Global Child Poverty and Well-Being. Measurement, Concepts, Policy and Action. Edited by: Minujin A, Nandy S. 2012, Bristol: Policy Press, 57-101.

    Chapter  Google Scholar 

  45. Howe LD, Galobardes B, Matijasevich A, Gordon D, Johnston D, Onwujekwe O, Patel R, Webb EA, Lawlor DA, Hargreaves JR: Measuring socio-economic position for epidemiological studies in low- and middle-income countries: a methods of measurement in epidemiology paper. Int J Epidemiol. 2012, 41: 871-886. 10.1093/ije/dys037.

    Article  PubMed  PubMed Central  Google Scholar 

  46. Hosseinpoor AR, van Doorslaer E, Speybroeck N, Naghavi M, Mohammad K, Majdzadeh R, Delavar B, Jamshidi H, Vega J: Decomposing socioeconomic inequality in infant mortality in Iran. Int J Epidemiol. 2006, 35: 1211-1219. 10.1093/ije/dyl164.

    Article  PubMed  Google Scholar 

  47. Pradhan J, Arokiasamy P: Socio-economic inequalities in child survival in India: a decomposition analysis. Health Policy. 2010, 98: 114-120. 10.1016/j.healthpol.2010.05.010.

    Article  PubMed  Google Scholar 

  48. van Malderen C, van Oyen H, Speybroeck N, Ogali I, Sparks C: Contributing determinants of overall and wealth-related inequality in under-5 mortality in 13 African countries. J Epidemiol Community Health. 2013, 67: 667-676. 10.1136/jech-2012-202195.

    Article  PubMed  Google Scholar 

  49. Chalasani S: Understanding wealth-based inequalities in child health in India: a decomposition approach. Soc Sci Med. 2012, 75: 2160-2169. 10.1016/j.socscimed.2012.08.012.

    Article  PubMed  Google Scholar 

  50. Gaber S, Patel P: Tracing health system challenges in post-conflict Côte d’Ivoire from 1893 to 2013. Global Public Health. 2013, 8: 698-712. 10.1080/17441692.2013.791334.

    Article  PubMed  Google Scholar 

  51. O’Hare BA, Southall DP: First do no harm: the impact of recent armed conflict on maternal and child health in Sub-Saharan Africa. J R Soc Med. 2007, 100: 564-570. 10.1258/jrsm.100.12.564.

    Article  PubMed  PubMed Central  Google Scholar 

  52. Ghobarah HA, Huth P, Russett B: The post-war public health effects of civil conflict. Soc Sci Med. 2004, 59: 869-884. 10.1016/j.socscimed.2003.11.043.

    Article  PubMed  Google Scholar 

  53. Southall D: Armed conflict women and girls who are pregnant, infants and children; a neglected public health challenge. What can health professionals do?. Early Hum Dev. 2011, 87: 735-742. 10.1016/j.earlhumdev.2011.08.020.

    Article  PubMed  Google Scholar 

  54. Bornemisza O, Ranson MK, Poletti TM, Sondorp E: Promoting health equity in conflict-affected fragile states. Soc Sci Med. 2010, 70: 80-88. 10.1016/j.socscimed.2009.09.032.

    Article  PubMed  Google Scholar 

  55. Victora CG, Fenn B, Bryce J, Kirkwood BR: Co-coverage of preventive interventions and implications for child-survival strategies: evidence from national surveys. Lancet. 2005, 366: 1460-1466. 10.1016/S0140-6736(05)67599-X.

    Article  PubMed  Google Scholar 

  56. Caulfield LE, de Onis M, Blössner M, Black RE: Undernutrition as an underlying cause of child deaths associated with diarrhea, pneumonia, malaria, and measles. Am J Clin Nutr. 2004, 80: 193-198.

    CAS  PubMed  Google Scholar 

  57. Hanf M, Nacher M, Guihenneuc C, Tubert-Bitter P, Chavance M: Global determinants of mortality in under 5s: 10 year worldwide longitudinal study. BMJ. 2013, 347: f6427-10.1136/bmj.f6427.

    Article  PubMed  PubMed Central  Google Scholar 

  58. Wagstaff A: Child health on a dollar a day: some tentative cross-country comparisons. Soc Sci Med. 2003, 57: 1529-1538. 10.1016/S0277-9536(02)00555-5.

    Article  PubMed  Google Scholar 

  59. Chan M, Kazatchkine M, Lob-Levyt J, Obaid T, Schweizer J, Sidibe M, Veneman A, Yamada T: Meeting the demand for results and accountability: a call for action on health data from eight global health agencies. PLoS Med. 2010, 7: e1000223-10.1371/journal.pmed.1000223.

    Article  PubMed  PubMed Central  Google Scholar 

  60. Ye Y, Wamukoya M, Ezeh A, Emina JBO, Sankoh O: Health and demographic surveillance systems: a step towards full civil registration and vital statistics system in sub-Sahara Africa?. BMC Public Health. 2012, 12: 741-10.1186/1471-2458-12-741.

    Article  PubMed  PubMed Central  Google Scholar 

  61. Ngom P, Binka FN, Phillips JF, Pence B, Macleod B: Demographic surveillance and health equity in sub-Saharan Africa. Health Policy Plan. 2001, 16: 337-344. 10.1093/heapol/16.4.337.

    Article  CAS  PubMed  Google Scholar 

Pre-publication history

Download references

Acknowledgements

This work was supported by a fellowship within the Postdoc-Programme of the German Academic Exchange Service (DAAD). We thank Jo Vearey and Liz Thomas (University of the Witwatersrand), Kouassi Lucien, Massoma Bakayoko, Abdoul Karim Traoré, and Samassi Daouda (Institut National de la Statistique, Côte d’Ivoire), Adama Sanogo Pongathié (Direction de l’Information de la Planification et de l’Evaluation), and Bédia François Aka (Université de Bouaké) for their help in obtaining access to relevant data. In addition, we would like to thank Martin Siegel from Technische Universität Berlin for advice on the measurement of inequalities.

Author information

Authors and Affiliations

  1. Department of Health Care Management and Berlin Centre for Health Economics Research (BerlinHECOR), Technische Universität (TU) Berlin, Straße des 17. Juni 135, Berlin, 10623, Germany

    Wilm Quentin

  2. Primary Health Care & Nutrition Unit, College of Medicine of the University of Lagos, PMB, Lagos, 12003, Nigeria

    Olayinka Abosede

  3. Institut National de Santé Publique, Abidjan BPV 47, Côte d’Ivoire

    Joseph Aka, Kouassi Dinard & Marguerite Te Bonle

  4. School of Public Health, University of Ghana, P.O. Box LG 13, Legon, Ghana

    Patricia Akweongo

  5. African Population and Health Research Centre, P.O. Box 10787–00100, Nairobi, Kenya

    Alex Ezeh

  6. Social Research Centre, American University in Cairo, El Tajomee El Khames, New Cairo, Egypt

    Ramadan Hamed

  7. Ecole de Santé Publique, Université de Kinshasa, BP 11850, Kinshasa 1, Congo

    Patrick Kalambayi Kayembe

  8. School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia

    Getnet Mitike

  9. Ifakara Health Institute, Plot 463, Kiko Avenue, Mikocheni, Off Mwai Kibaki Road, P.O. Box 78373, Dar es Salaam, Tanzania

    Gemini Mtei

  10. Department of Health Services Management, Munich School of Management, Ludwig-Maximilians-Universität, Schackstraße 4, Munich, 80539, Germany

    Leonie Sundmacher

Authors
  1. Wilm Quentin
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Olayinka Abosede
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Joseph Aka
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Patricia Akweongo
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Kouassi Dinard
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Alex Ezeh
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Ramadan Hamed
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Patrick Kalambayi Kayembe
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Getnet Mitike
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Gemini Mtei
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Marguerite Te Bonle
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Leonie Sundmacher
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Wilm Quentin.

Additional information

Competing interests

The authors declare that they have no competing interests.

Authors’ contributions

WQ and LS conceptualized the study, which was then designed in collaboration by all authors. WQ, JA, KD and MTB assured data collection in Côte d’Ivoire. All authors helped to interpret the data from their respective cities. WQ drafted the manuscript. All authors critically revised and approved the final manuscript.

Electronic supplementary material

12916_2014_979_MOESM1_ESM.docx

Additional file 1: Box S1. On the DHS sampling procedure and the use of sample weights. Table S1. National child mortality rates in countries and DHS surveys included in this study. Table S2. Mean wealth index scores by income quintile across 10 African cities. (DOCX 18 KB)

Authors’ original submitted files for images

Below are the links to the authors’ original submitted files for images.

Authors’ original file for figure 1

Authors’ original file for figure 2

Rights and permissions

This article is published under license to BioMed Central Ltd. licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Quentin, W., Abosede, O., Aka, J. et al. Inequalities in child mortality in ten major African cities. BMC Med 12, 95 (2014). https://doi.org/10.1186/1741-7015-12-95

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/1741-7015-12-95

Keywords

  • Socioeconomic factors
  • Urban health
  • Child mortality
  • Africa
  • Social justice

BMC Medicine

ISSN: 1741-7015

Contact us