Statistical analysis of early marriage among women in Ethiopia by using multilevel logistic regression

Early marriage is still widely practiced in many parts of the world mainly in Latin America, the Caribbean, Southern Asia and countries of Africa. Ethiopia has one of the highest rates of early marriage in Sub-Saharan Africa. The main objective of this study was to identify determinants of early marriage among women in Ethiopians and to examine variations in early marriage between and within regions of Ethiopia. The study is made based on the Ethiopian Demographic and Health Survey 2011 data that has two stages sampling hierarchical structure, collected for 9262 married women nested within eleven regions with age 15-49 years. Descriptive statistics and multilevel logistic regression model analysis were used to examine the prevalence and identify determinants of early marriage. The results of descriptive statistics shows that Out of the 9,262 married women, 3320(35.8%) of marriages occur 18 years and above while 5942 (64.2%) of these women married early (under 18 years) at the time of the survey. The multilevel logistic regression analysis showed that there is a signifi cant difference in early marriage across regions. Accordingly, for empty model, the variance is estimated as 2 0  =0.3077789, p-value=0.0108 revealing that there was a signifi cant difference in early marriage across 11 regions. The variance of random intercept is estimated at 0.160928, p-value=0.012. This is due to the inclusion of fi xed predictor variables indicating that the additional predictors did not increase the percentage of variance explained by the model. Furthermore, either empty model or random intercept model revealed that there was a signifi cance variation in early marriage across regions. Similarly, results of random coeffi cient for the selected few predictor variables, showed that women’s education level found to be signifi cant in explaining variations in early marriage across the regions. As a result special attention needs to be paid, in particular, to the regions’ access to education for young women and information on reproductive health to reduce early marriage. Research Article Statistical analysis of early marriage among women in Ethiopia by using multilevel logistic regression Tezera Abebe Gashaw* Department of Statistics, College of Natural and Computational Science, Wolkite University, Ethiopia Received: 18 March, 2019 Accepted: 13 April, 2019 Published: 16 April, 2019 *Corresponding author: Tezera Abebe Gashaw, Department of Statistics, College of Natural and Computational Science, Wolkite University, Ethiopia, Email:


Introduction
Marriage is an important institution for the individual and the society at large. For the individual, it is a signifi cant and memorable event in one's life cycle as well as the most important foundation in the family formation process. Age at marriage is of particular interest because it marks the transition to adulthood in many societies; the point at which certain options in education, employment, and participation in society are foreclosed; and the beginning of regular exposure to the risks of pregnancy and childbearing. For the society as a whole, it unites several individuals from different families and represents the creation of a production and consumption unit as well as one for the exchange of goods and services [1].
The term "early marriage" is used to refer to both formal marriages and informal unions in which a girl lives with a partner as if married before age of 18 [2]. Early marriage, also known as Child marriage, is defi ned as "any marriage carried out below the age of 18 years, before the girl is physically, physiologically, and psychologically ready to shoulder the responsibilities of marriage and childbearing." Child marriage, on the other hand, involves either one or both spouses being children and may take place with or without formal registration, and under civil, religious or customary laws [3]. Early marriage affects millions of children through the world. It is widely practiced in the countries of South Asia where every year millions of girls-preteens and teens become the wives of older men. Early marriage compromises their development and often results in early pregnancy and social isolation, with little education and poor vocational training reinforcing the gendered nature of poverty. Required to perform heavy amounts of domestic work, under pressure to demonstrate fertility, married girls and child mothers face constrained decision-making and reduced life choices. Both boys and girls are affected by child marriage but the issue impacts girls in far larger numbers, with more intensity and is wide ranging [2]. Early marriage is still widely practiced in many parts of the world but remains prevalent in countries of Africa, Latin America and the Caribbean as well as Southern Asia and predominantly affects girls. It is estimated DOI: http://dx.doi.org/10.17352/gjfr.000011 that, if nothing changes, a 100 million young girls aged 15 years or less will be married within the present decade [4].
Regional estimates of its occurrence for girls include 48% in Southern Asia, 42% in Africa and 29% in Latin America and the Caribbean with wide differentials across the countries. In the West African sub-region, the proportions of girls affected vary from 28% -43% (Ghana, Togo, Cote d'Ivoire, Senegal, Benin, Nigeria) to 60-80% (Burkina Faso, Guinea, Mali, Chad and Niger) [2].
Current estimates show that approximately 82 million girls between 10-17 years will be married before they reach 18 years.
Of the 331 million girls aged 10-19 in developing countries (excluding China), 163 million will be married before they are 20 .Although early marriage is predominantly a female problem, a minority of boys may also be forced to marry early [5].
Ethiopia has one of the highest rates of early marriage in Sub-Saharan Africa. A study by the National Committee on Harmful Traditional Practices of Ethiopia (NCTPE) estimated the proportion married before the age of 15 at 57 percent. The same study shows that the practice occurs in its more extreme forms in northern Ethiopia, where girls are married as young as eight or nine years of age. In some instances, they are even pledged at birth [6]. Although early marriage is widely practiced in many parts of the country, rates in Amhara and Tigray region are much higher than the national average (82 percent in Amhara, 79 percent in Tigray, 64 percent in Benshangul, 64 percent in Gambella and 46 percent in Afar [6].
Women who marry early will have, on average, a longer period of exposure to the risk of pregnancy, often leading to higher fertility. Historically, societies with later age at fi rst marriage have experienced decreased fertility rates while in traditional populations in Asia and Africa where age at fi rst marriage is younger, high levels of fertility has been observed [7][8][9]. Many demographers and scholars recommend the need to conduct in-depth studies on the risk factors of early marriage among women for both developing and developed countries. Child marriage is a health issue as well as a human right violation. Because it takes place almost exclusively within the context of poverty and gender inequality, it also has social, cultural and economic dimensions. Most countries, including Ethiopia, have declared 18 as a minimum legal age of marriage.
In Ethiopia marriage is universal and occurs early). In 2005, for instance, among women aged 25 -49, 66% married by before age 18 while the proportion married by age 20 is 79% with median age at fi rst marriage of 16.1 years [10].
The people of Ethiopia are multi-ethnic and multi-cultural.
Due to the multi-ethnic and multi-cultural nature of the society, the ways of controlling early marriage varies within societies (women) and across regions. Moreover, socio-economic and demographic factors on early marriage may cause variation at individual and regional levels. Yet, there is no study conducted about early marriage among women in Ethiopia particularly about the effects of socio-economic, and demographic factors aiming at identifi cations of individual and regional variations. Therefore, this study is an attempt to fi ll the research gap by identifying the socio-economic and demographic factors of early marriage, the extent of variations and the factors that vary across regions of Ethiopia. This intern helps to increase age at fi rst marriage (decrease early marriage).

Study variables
Dependent variable: During the survey all women were asked a series of questions regarding their marital status and whether they had ever lived with a man. All those who reported that they were ever married or ever-lived with a man, were asked to indicate how old they were at the time when they started, for the fi rst time ever, living with a man as a wife, irrespective of the legality or otherwise of their union. The response to this question constitutes the woman's age at fi rst marriage. All the women who indicated that they had never been in a union or lived with a man were considered single and as a result they were not asked the question about the age at fi rst marriage. This is the standard way in which age at fi rst marriage is being measured in the worldwide DHS program [1].

Multilevel logistic regression model
In this analysis, a multilevel statistical approach was used to model the relation between age at fi rst marriage and the explanatory variables. Two levels of data hierarchy were stated

Types of multilevel logistic regression models
It must be decided on two aspects, fi rst including which predictors are to be included in the analysis, if any. Secondly, it must be decided whether parameter values (i.e., the elements that will be estimated) will be fi xed or random. Fixed parameters are composed of a constant over all the groups, whereas a random parameter has a different value for each of the groups. Additionally, it must be decided whether to employ a maximum likelihood estimation or a restricted maximum likelihood estimation type [11].
Solving for we have:

Random Slope Model:
Notice that now the slope is also allowed to vary across regions. The slopes equation specifi es that the slope coeffi cient is a linear combination of the average slope () and the regional effect (U). Consider explanatory variables which are potential explanations for the observed outcomes. Denote these variables by. 1 2 k are indicated in the usual way by hij X . Since some or all of these variables could be levelone variables, the success probability is not necessarily the same for all individuals in a given group. Therefore, the success probability depends on the individual as well as the group, and is denoted by ij P . Now consider a model with group-specifi c regressions of logitof the success probability,   ij logit P , on a single level one explanatory variable X, There are two random group effects, the random intercept 0 j U and the random slope 1j U . It is assumed that the level two residuals oj U and 1j U have both zero mean given the value of the explanatory variable X. Thus, 1  is the average regression The fi rst part of equation (5)

Results of descriptive analysis
Out of a total of 9,262 married women, 3320 (

Results of multilevel logistic regression analysis
The data used in this study have a hierarchical structure.
Units at one level are nested within units at the next higher level.
Here, the lower level (level-1) units are the Individualwomen and the higher level (level-2) units are the regions that constitute the groups into which the women are clustered or nested. The nesting structure is women within regions that resulted in a set of 11 regions with a total of 9262 women.
Before we proceed to multilevel logistic regression analysis, we need to test the heterogeneity age at fi rst marriage among women across eleven regions of Ethiopia.
A chi-square test was applied to assess heterogeneity in the proportion of women who were married early among the 11 regions. The test yield X 2 =573.229, df =10, P<0.001. Thus, there is evidence for heterogeneity with respect to age at fi rst marriage across regions.
First, an empty model with random effect and no covariates was examined for the over all probability of early marriage.
Second, a multilevel model for random effect and a fi xed slope covariate was examined for early marriage. and fi xed slope model in describing early marriage (Table   2). Furthermore, the signifi cant deviance-based chi-square value for random coeffi cient model indicates that the random coeffi cient model is better than the multiple logistic regression models in explaining early marriage (Table 2). Finally; a random coeffi cient multilevel logistic regression model with random effect for early marriage was analyzed.

The Empty Random Intercept Logistic Regression Analysis:
The  Table   4). The estimated coeffi cients and odds ratio have similar interpretation like in ordinary logistic regression [14]. Random part has additional information which is discussed below.
The random part of random intercept and fi xed slope that there is a signifi cant regional random effect variation on early marriage among women (Table 4). This implies that there is still unexplained variation on early marriage across regions.    (Table 5).  have on average higher slopes and the negative sign for the correlation between intercepts and slopes implies that regions with higher intercepts tend to have on average lower slopes on the corresponding predictors.

Discussion of the Result
This study was intended to identify socio-economic and demographic determinants of early marriage among women based on Ethiopian Demographic and Health Survey (EDHS, 2011) data. Accordingly, descriptive analysis, and multilevel logistic regression analysis were used. The results which are obtained are discussed as follows. The descriptive analysis of the study revealed that the prevalence of early marriage was 64.2 %. The proportion of early marriage of women varied from one region to the other in Ethiopia. The highest proportion (85.5%) of early marriage women was observed in Amahara followed by Benshangul-Gumez (72.3%) and the least proportion (37.4%) of early marriage was observed in Addis Ababa, followed by Dire Dawa (47.2%). Hence, there appears to be some variation in the proportion of early marriage among women in different regions of Ethiopia (Table 1). This could be due to the desire of the family to keep one's good name and social esteem and (mostly of fathers), to create bonds or relationships with families of their choice. The other possible reason might be Tradition and cultural values of the region. Therefore region has statistically signifi cant effect on early marriage. This result is consistent with [15].
In the multilevel analysis, women are considered as nested within the various regions in Ethiopia. Three multilevel models: empty model, random intercept and random slope or random coeffi cient model were fi tted in order to explain regional differences in early marriage. Before the analysis of data using the multilevel approach, we need to test the heterogeneity age at fi rst marriage among women across eleven regions of Ethiopia. A chi-square test was applied to assess heterogeneity in the proportion of women who were married early among the 11 regions. Thus, there is evidence for heterogeneity with respect to age at fi rst marriage across regions. Such heterogeneity is a requirement in the multilevel analysis. Following this, three multilevel logistic regression models were fi tted for the national sample as a whole The multilevel logistic regression model provided interesting relationships that would not be evident from a simple; singlelevel analysis. We showed that there is a signifi cant variation of early marriage between regions. This may suggest differences in lifestyle, culture, ethnic or environmental determinants between different regions. Because of these potential cultural, socioeconomic and environmental differences, early marriage exhibits a signifi cant variation among regions of Ethiopia. In the empty with random intercept model and random intercept and fi xed slope models, the overall variance of the constant term was found to be statistically signifi cant, which indicates the existence of differences in early marriage among married women across regions.
According to the result of the random intercept with fi xed slope model, the fi xed part showed that, religion (Orthodox and Muslim), women's education level, husband's education level, Place of resident, exposure to any media, respondents work status and wealth index were found to be signifi cant determinants of variation in early marriage in all regions with respect to the corresponding reference categories (Table 4) were as occupation of husband's and number of siblings are not signifi cant Women who had no education, primary and secondary were more likely to be married early (OR=4.95, 4.41 and 2.21) respectively compared to women with higher education level controlling for other variables in the model (Table4). The signifi cance level for all education categories were signifi cant and thus risk of getting early marriage increased as the level of education decreased. These results provide empirical evidence that a woman's educational level is an important determinant of early marriage in Ethiopia. Less or no education leads to increased early marriage and therefore lower levels of education are associated with a higher probability of early marriage. The results obtained clearly showed that education has a statistically signifi cant and strong delaying effect on early marriage. A lower risk of getting married early among educated women may be due to waiting time for schooling. This fi nding is supported by previous studies [16]. Husband's education level is also showed signifi cant effect on early marriage.
The fi ndings of this study also show that women who lived in rural area is more likely to get early marriage than women who lived in urban. This could be rural areas tend to have institutional and normative structures such as the kinship and extended family that promote early marriage and it also might be People in urban areas need to develop skills, gain resources and achieve maturity to manage an independent household and thus they might be delay marriage. This fi nding is consistent with other studies [17,18].
Religion of women was also found one of the determinants of early marriage. Married women who were followers of Coptic Orthodox religion were more likely to exercise early marriage than those who were followers of religions other than Protestant and Muslim. Similarly Muslim married women were more likely toget early marriage compared to those religions other than Coptic Orthodox and Protestant. This is in agreement with the fi ndings in other studies [15,16].
Household economic status (wealth index) is one of the most important determinants of early marriage among married women in Ethiopia. According to our fi ndings, as compared with women residing in richest economic status households (wealth index), the risks of being early marriage in richer and poorer households were highly signifi cant. This could be because of early marriage as a way to improve the economic status of the family, arguing that poverty forces families to marry their daughters at a young age. This is in agreement with the fi ndings in other studies [2,19]. Access to mass media is one of the important effective factors that infl uence early marriage.
The result indicated that women who do not exposure to any mass media via radio, TV or newspapers/magazine have more likely to get early marriage compared to exposure to any mass media. This fi nding is consistent with other studies [19].
The random coeffi cient model showed that the random regions and a model with a random coeffi cient is more appropriate to explain the regional variation than a model with fi xed coeffi cients or empty model with random effects

Conclusions
The descriptive analysis of the study revealed that the prevalence of early marriage was 64.2 %.The study revealed that socio-economic and demographic variables have signifi cant effect on early marriage among women in Ethiopia. According to the result of the random intercept with fi xed slope model, the fi xed part showed that, religion (Orthodox and Muslim), women's education level, husband's education level, Place of resident, exposure to any media, respondents work status and wealth index were found to be signifi cant determinants of variation in early marriage in all regions with respect to the corresponding reference categories.
In the multilevel analysis, the random parts of the intercept and the coeffi cients provided additional information. In the empty with random intercept model and random intercept and fi xed slope models, the overall variance of the constant term was found to be statistically signifi cant, which indicates the existence of differences in early marriage among married women across regions. The random coeffi cient model showed that the random effects of women's education level vary across regions in explaining early marriage. Further this model implies that there exist considerable differences in early marriage across regions and a model with a random coeffi cient is more appropriate to explain the regional variation than a model with fi xed coeffi cients or empty model with random effects.

Recommendations
In light of the research fi ndings, the following recommendations are forwarded. As there is variation in the status of early marriage in regional states of Ethiopia; it is recommended that regions have to take policies and programs that address the problem taking into account the context of the region. It is also crucial to continue improving girls and young women access to education in the country, as this is important avenue for increasing the women's age at fi rst marriage.
Similarly, it is advisable to target young women, particularly those with no or little education, for providing information on reproductive health and basic life skills to enable them avoid early sexual activity and ultimately early marriage. These should include primary school girls.

Limitation of the study
This study includes only ever-married women. This may bias downward age at fi rst marriage because women in the older group who had not married were not included. Limited literature on Ethiopia related to the subject and the problem of missing values and non-response rate and inconsistence answers for some variables were the main root limitations of this study. Finally it is quantitative research.