International Journal of Statistics and Applications 2013, 3(3): 50-58 DOI: 10.5923/j.statistics.20130303.03 Poverty Levels and Maternal Nutritional Status as Determinants of Weight at Birth: An Ordinal Logistic Regression Approach Oladipupo B. Ipadeola 1,* , Samson B. Adebayo 2 , Je nnife r Anyanti 3 , Emmanuel T. Jolayemi 4 1 Malaria Action Program for States, Abuja, Nigeria 2 National Agency for Food, Drug Administration and Control, Abuja, Nigeria 3 Society for Family Health, Research and Evaluation Division, Abuja, Nigeria 4 Department of Statistics, University of Ilorin, Ilorin, Nigeria Abstract This paper explores the possible influence of household poverty levels and maternal nutritional status on child’s weight at birth. The 2003 Nigeria Demographic Health Survey (NDHS) measures weight at birth on an ordinal scale. Therefore, modelling techniques that take cognizance of ordinal responses are suitable for this situation. Ordinal logistic regression technique was employed for all analyses. Quintiles of wealth index were used as a measure of assets owned by households while body mass index was used to assess maternal nutritional status. Other demographic characteristics such as mother’s age at birth of the child, educational attainment, locality (urban/rural) and geo-political zones were controlled for in the models. The sample size for survey was 5138. Wealth index and maternal nutritional status were positively associated with child’s weight at birth, while mother’s educational attainment was not statistically significant. Significant and positive association of wealth index was evident with middle and richest when compared with those in the poorest category of wealth index. Mothers that were underweight are less likely to give birth to heavier children while those that were overweight or obese are more likely to give birth to children with heavier weights compared with mothers with normal BMI. Keywords Proportional Odds Ratio, Nigeria Demographic and Health Survey, Wealth Index, Cut-off Points, Cumulative Logistic Regression 1. Introduction Child’s weight at birth has been shown to be associated with child’s and maternal health; which in turn could be a determining factor of maternal and child mortality before, during and after birth. This may also be related to many factors, both physical and physiological. Among such factors that have been investigated in the past were maternal and paternal weights and heights, ethnicity, gestational age, birth order, maternal education, mother’s age at the birth of child and race[1][2][3][4]. Other possible determinants of child’s weight at birth that have been considered in literature were: paternal education, socio-economic status, prenatal care, method of delivery (either normal or through caesarean), child’s sex, maternal smoking status, consumption of alcohol, and use of psychoactive drugs duringpregnancy[5][6][7][8] [9]. It was observed that maternal weight had a greater influence on birth weight, while maternal and paternal height contributions were similar in nature[2]. Furthermore, weight * Corresponding author: ladiipadeola@yahoo.com (Oladipupo B. Ipadeola) Published online at http://journal.sapub.org/statistics Copyright © 2013 Scientific & Academic Publishing. All Rights Reserved and height of father and mother contributed equally to infant’s weight gain. Low birth weight (LBW) i.e. birth weight less than 2.5 Kilograms (KG), as a result of preterm birth or intrauterine growth retardation, is the strongest single factor associated with peri-natal, neo-natal, post-natal and infant mortality. Birth weight is related to health outcomes in childhood, such as neurological deficits and lower cognitive skills[10][11] as well as in adulthood; such as high blood pressure, diabetes, coronary heart disease and stroke[12][13][14][15]. LBW remains a substantial public health concern even in industrialized countries. It is more common among blacks than whites[16]. In addition, socio-economic factors have been suggested in literature[5][17]. Worldwide, it is estimated that 15.5% of all live birth per year are LBW, and more than 95% of LBW infants are born in developing countries[18] Birth weight is also an important determinant of weight gain after birth. While low birth weight is associated with increased risk of morbidity and mortality in newborns and during infancy, excessive weight is associated with decreased maternal amino acids[19] Decreased foetal growth may result from a limitation in the nutrient supply to the foetus. Research has also linked small size at birth to