Trends and patterns of childhood mortality clustering in Nigeria

Joshua O. Akinyemi, University of Ibadan
Olusola Ayeni, University of Ibadan
Afolabi Bamgboye, University of Ibadan

Though some progresses have been made in improving child survival, however, the childhood mortality rates are still high in Nigeria and many developing countries. Child deaths can be concentrated / clustered at the level of the mother/family, households, community and region. Such correlated observations violate the assumption of independence during statistical analyses and they will result in biased and inconsistent estimates. Majority of studies that have explored the phenomenon in the past used frailty models which account for both death clustering and unexplained heterogeneity (unmeasured covariates) in childhood mortality. The concept of unexplained heterogeneity is quite different from death clustering, so using a single model to suggest both is conceptually questionable. In this paper, a nationally representative data is used to exclusively explore childhood death clustering in Nigeria. This study is based on data from the Nigeria Demographic Health Survey (NDHS) rounds of 1990, 2003 and 2008. Three measures of childhood mortality clustering were derived. These measures were computed for each of the NDHS and bivariate and multivariate analyses was done to elucidate the pattern of mortality clustering according to selected background characteristics. Preliminary results showed that the overall level of childhood mortality clustering is high and seems not to have changed much between 1990 and 2008 NDHS. The proportion of women losing two or more children merely moved from 24% in 1990 to 22.7% in 2008. Child losses among these women accounted for 77% and 75% of all child deaths in 1990 and 2008 respectively. Though, the 2008 NDHS report indicated that childhood mortality is on a decline, mortality clustering levels has not changed in a commensurate manner. This is suggestive of inequitable distribution of health-related resources or existence of problems specific to some families/communities.