child health inequalities in nigeria: magnitude and...

Journal of Global Health Perspectives | jglobalhealth.org

Journal of Global Health Perspectives | jglobalhealth.org | December 21, 2013 Copyright © 2013 First Aid WorldWide. All rights reserved.

Child Health Inequalities in Nigeria: Magnitude and Determinants of Mortality in Children Under Five

Adeniyi A. Adeboye MBBS, MS, MPH1†, Olusimbo K. Ige MBBS, MSc2,

Rafeek A. Yusuf MBBS1, 3

1University of Texas Health Science Center at Houston School of Public Health, Houston, TX, USA 2Department of Community Medicine, University College Hospital, Ibadan, Nigeria

3University of Texas Health Science Center at Houston School of Biomedical Informatics, Houston, TX, USA †Corresponding author: [email protected]

Abstract

This study aimed to assess the magnitude of inequalities in mortality in children under the age of five (U5M) across socio-cultural groups and to evaluate the social determinants of U5M in Nigeria. A cross-sectional study using the dataset of women in reproductive age group obtained from the 2008 Nigeria Demographic Health Survey was examined. Mortality among children under five born to women between the years 2003-2008 was explored. The relative gap between U5M was estimated and determinants of U5M were explored with logistic regression analysis. Wide inequalities were observed across population groups. Rural areas had 41% higher U5M than urban areas and families in the poorest wealth quintile had double the U5M of the richest. U5M inequality was greater in urban than rural groups. There were also variations by ethnicity and the gradient of U5M favored the southern zones of the country. The predictors of U5M were: increasing paternal age, Hausa ethnicity, living in the northern regions of the country, lack of formal education of mothers and being in the lowest wealth quintile. These inequalities in U5M will continue to impede the attainment of the Millennium Development Goal targets for Nigeria unless decisive actions are taken.

ORIGINAL RESEARCH

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Background The differentials in population health including children have given rise to the concept of health inequalities, which is now one of the most explored questions in public health [1]. Child mortality is often used as a measure of population health since it reflects the social, economic and environmental conditions in which children (and others in society) live, including their health care [2-3]. Under-five mortality (U5M) rate is also an indicator of the Millennium Development Goals (MDGs) [2]. Child mortality in Africa has remained the highest in the world particularly in its sub-Saharan, region [4]. In Nigeria, child survival indicators have remained low with the country ranking among the top 20 countries with the worst child survival indicators in the world [5]. Although substantial inequalities in child health have been documented in most countries of the world these inequalities tend to be far larger in low and middle-income countries. The recognition that childhood health and mortality are heavily influenced by patterns of inequality has made the reduction in disparities in childhood mortality within developing countries a main target of national governments and international organizations [6]. However, a prerequisite for achieving this goal is to establish how large these differences are and to identify the groups at risk of high mortality rates. There are few studies that have described the existing inequalities in mortality in children under the age of five (U5M) in less-developed countries and even fewer that have sought to explain them. This study therefore aimed to assess the magnitude of inequalities in under-five mortality rates across socio-cultural groups in Nigeria and to evaluate the social determinants of U5M in Nigeria. Methods Nigeria is made up of 36 states and a Federal Capital Territory. The country is grouped into six geopolitical regions: North Central, North East, North West, South East, South-South and South West. At present there are about 374 identifiable ethnic groups, but the Igbo, Hausa, and Yoruba are the major groups. Nigeria is home to over 140 million people. This makes Nigeria the most populous nation in Africa and the tenth most populous in the world. About 41.5% of the population is less than 15 years; about half of these are less than five years of age. There is rapid urbanization with 47% of Nigerians now living in urban areas. With an annual per capita income of barely $300, Nigeria is one of the 20 poorest countries in the world [7]. Data on under-five mortality were obtained from the 2008 Nigeria Demographic Health Survey (DHS) datasets. The DHS survey is a cross-sectional study that was implemented by the National Population Commission from June to October 2008 on a nationally representative sample of more than 36,000 households [7]. The 2008 DHS is the fourth national demographic and health survey conducted in the country. Data was obtained from the dataset of the 18,028 women in the reproductive age group (15-49 years) who had a live birth within the five years preceding the study (2003-2008). Further analysis was conducted with Statistical Package for Social Sciences (SPSS) version 16. Permission to use NDHS datasets was obtained from MEASURE Demographic Health Survey group. Under-five mortality rate (U5MR), the dependent variable, was measured as the number of deaths of children from birth to age five per 1000 live births. Independent variables were: wealth quintiles (the lowest quintile being the poorest and the fifth quintile the richest), location of residence, geo-political zone, educational level and age of parents, ethnicity, access to safe water and sanitary toilet facilities. Source of drinking water was classified as safe if it was pipe borne, from a bore hole, a protected well or bottled water and unsafe if it

CHILD HEALTH INEQUALITIES IN NIGERIA

Journal of Global Health Perspectives | jglobalhealth.org | December 21, 2013

Copyright © 2013 First Aid WorldWide. All rights reserved.

was from an unprotected well or surface water [8]. A toilet facility was classified as sanitary if it was a flush toilet, ventilated, improved pit latrine or pit latrine with a cover. Unsanitary toilets include uncovered pit latrines, composting toilets, bucket toilets or no facility [8]. Inequalities in the U5MR were interpreted in comparative terms, by contrasting the under five mortality rates across population groups (difference in rates as a percentage of the best comparison group) [9]. This measure, which is called the "relative gap", is chosen because it is easy to interpret [10]. The statistical significance of the relative gaps was tested with the Chi square test. The social determinants of under-five mortality (proportions of women who had experienced at least one under-five mortality between 2003 and 2008 were explored with binary logistic regression analysis at a level of significance of 5%. The sample characteristics of respondents are shown in Table 1. Rural dwellers constituted the majority (73.2%) of respondents. The proportion of respondents who lived in the North-West region of the country was the largest (27.1%) followed by the North-East region (22.0%). Those in the poorest wealth quintile were more than a quarter (26.4%) while those living in households with unsafe water sources and unsanitary toilet facilities constituted more than 50% of the study sample (See Table 1 below). Table 1: Distribution of respondents

Number = 18,028 Percentage (%)

Location:

Rural 13,203 73.2

Urban 4,825 26.8

Region:

North Central 3,350 18.6

North East 3,972 22.0

North West 4,888 27.1

South East 1,454 8.1

South West 2,101 11.7

South South 2,263 12.6 Results The mean age of respondents (mothers) was 29.8±7.4 years while the mean age for the fathers was 40±10.4 years. A large proportion of both mothers and fathers had no formal education: 41% of the mothers and 49.2% of the fathers. Only 11.2% of fathers and 5.2% of mothers had up to a tertiary level of education (See Figure 1 below).

ORIGINAL RESEARCH


Figure 1: Parents’ educational levels

The overall U5MR for the country was 191/1,000 live births. There are inequalities in U5MR per social and geographic characteristics of respondents. The rural areas had an approximately 40.9% increase in mortality compared to the urban areas. The rural: urban ratio was 186:132. With regards to ethnicity, the U5MR for the Hausa was more than double that of the Yoruba (See Figure 2 below).




Figure 2: U-5MR per 1,000 live births across the major ethnic groups

The worst hit north-western zone had 121% excess U5MR compared to the south-south region of the country (See Figure 3 below).

ORIGINAL RESEARCH


Figure 3: Regional differences in U5M per 1,000 live births

93

153

182

142

206 204

0

50

100

150

200

250

South-‐South South-‐West South-‐East North-‐Central North-‐West North-‐East

U-‐5MR per 1000 live births

When U5MR was compared across parents' age groups, older mothers reported excess mortality ranging from 23-29% compared to mothers less than 20 years. However, among fathers, those at the extremes of age (< 20 and ≥50 years) fared worse than those 20-29 years. Mothers who had no formal education had more than 200% excess U5MR in comparison with mothers with post-secondary education. The households in the poorest wealth quintile had double the U5MR of those in the richest wealth quintile (relative gap of 101%). A consistent increase was seen in mortality from the richest to the poorest. The relative gaps were all statistically significant (p<0.05) for all groups (See Figure 4 below).




Figure 4: U-5MR per 1,000 live births across wealth quintiles for 2003-2008

The differences in the U5MR in the rural and urban areas were compared in each zone. In each of the zones, excess mortality was observed in the rural areas compared with the urban areas. This difference was largest in the South-South zone where a relative gap of 46.3% was observed. The range of the relative gap was wider in urban regions compared with the rural (38.8%-130%) versus (42.9%-100.9%) (See Figure 5 below).

ORIGINAL RESEARCH


Figure 5: Rural-urban comparison of U5MR per 1,000 live births across geo-political regions

The poorest urban households had higher mortality than the poorest rural households. It was also observed that the inequality in U5MR in urban groups was wider than the rural groups. The poorest had 2.4 times the mortality rates of the richest (140% relative gap) in the urban while in the rural the difference between the poorest was less than twice (1.7 times) that of the richest households (71% relative gap) (See Figure 6 below).




Figure 6: Comparison of U-5MR per 1,000 live births across wealth quintiles in urban and rural areas for 2003-2008, Nigeria

Table 2 shows the determinants of U5M, when other variables were adjusted. The significant determinants of U5M were fathers' age (fathers aged 20 -29 years had the lowest odds of U5M), being of Hausa ethnicity increased the odds of U5M by 1.5 times when compared to Yoruba. Living in the north-east, north-west and south-east regions of the country also increased the odds of U5M. Mothers who had no formal education had about twice the risk of U5M as mothers who had tertiary education. Compared to households in the richest wealth quintile those in the poorer and poorest households had higher odds of U5M.

ORIGINAL RESEARCH


Table 2: Predictors of U5M in Nigeria between 2003 and 2008

Variables Odds Ratio 95% CI P value Fathers age: ≥50 years 1.000 20-29 0.783 0.783- 0.652 0.008 30-39 0.848 0.740-0.972 0.018 40-49 0.869 0.768- 0.982 0.025 Ethnicity: Yoruba 1.000 Hausa 1.456 1.134-1.869 0.003 Region: South- south 1.000 North east 1.423 1.104- 1.833 0.006 North west 1.365 1.051 -1.774 0.020 South east 1.652 1.139- 2.396 0.008 South west 1.301 1.001- 1.692 0.049 Mothers’ level of education: Tertiary 1.000 None 2.004 1.449 -2.771 0.000 Primary 1.941 1.420 -2.654 0.000 Secondary 1.637 1.213 -2.210 0.001 Wealth Index: Richest 1.000 Poorest 1.278 1.013- 1.612 0.038 Poorer 1.332 1.072 -1.654 0.010 Variable not retained in the model: safe-water, mothers’ age, marital status, gender of household head, religion, partner’s education, access to sanitary toilet facilities Discussion This study explored inequalities and social determinants of under-five mortality in Nigeria. Wide inequalities in U5M across socio-cultural groups were demonstrated. The range of inequalities in U5M in Nigeria confirms that not much has changed since Nigeria's ranking as one of the top nations in the World Health Organization's inequality ranking [11]. These findings also reiterate those of other authors on the wide gaps in child mortality in many low and lower middle-income countries [12]. These continued inequalities in spite of the reduction in national averages in U5M are not uncommon in African countries [13]. This has important policy implications on the need for more equitable allocation of resources to bridge the identified gaps. Differentials in U5M by ethnicity were identified and this is similar to reports from other African countries (14-15). Ethnicity is especially relevant in Africa, since it often dictates entitlements to material and other resources important for child survival [16]. The relative gaps in mortality found in households in the lower wealth quintiles, although not unusual, seem to exceed those of other countries [3, 9, 13, 15]. This calls for more attention to pro-poor health interventions in Nigeria. Spatial variations in U5M were also observed with U5M




hot spots in the northern regions of the country replicating findings in Kenya [17], Ghana [18] and India [19]. Geographic variation in child mortality has been attributed to differences in climatic conditions in some countries since northern regions seem to have more arid climatic conditions unfavorable to child health compared to the south (Fotso 2006). However, in Nigeria, geographic variations in child survival show some congruence with other socioeconomic inequalities. Higher U5M mortality was consistently observed in rural areas compared with urban locations, an often reported finding [20-21], However, wider intra-urban relative gaps were observed which is a more recent phenomenon being reported in some large African cities [22-23]. The deleterious effects of being disadvantaged appear much larger in urban areas than in the rural. This foretells a further worsening in child health inequality in the country if the present trend in urbanization persists. The observed variation in under-five mortality in Nigeria was explained by fathers' age, ethnicity, region of residence, mothers' educational attainment and household wealth index. These findings are similar to those of other authors [24-28] except for the influence of the fathers' age. Fathers' age is a new finding which needs further exploration by other studies. Although living in an urban or rural area has long been one of the key variables for differentiating child mortality [29], its impact seems to disappear as other variables have superseded it as social determinants of under-five mortality in this study population. However, maternal education has remained one of the most important determinants of child survival in Nigeria. There can be no compromise on universal female education if child health indicators are to improve in Nigeria. A limitation of this study is that the possible effect of unobserved community factors which can also affect child health, such as food availability and air pollution, could not be explored due to the lack of data on these variables. Conclusion This paper contributes to the growing empirical literature on inequalities in under-five mortality in developing countries. It also demonstrates the changing rural-urban differentials in child mortality in a country with rapid urbanization amidst a declining economy. New insight has been provided into paternal characteristic – such as father’s age – as a potential predictor of U5M which requires further research. In addition, this study reinforces the emerging trend that residing in rural areas and being poor potentially offers higher chance of surviving till the fifth year of life when compared with being poor and residing in urban areas. Furthermore, the study reiterates the persistence of inequalities in U5M in Nigeria. The concentration of U5M among groups which are already the most disadvantaged begs for immediate intervention. Otherwise, these inequalities in child survival would continue to impede the attainment of the MDGs in Nigeria. Policies to improve the health status of the poor and address female education should therefore be an important focus of development policy in Nigeria. Studies monitoring trends in under-five mortality should also monitor within-country inequalities to assess the success of these policies. Acknowledgements We are grateful to the MEASURE DHS for the permission to use this DHS data set.

ORIGINAL RESEARCH


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child health inequalities in nigeria: magnitude and...

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