VARIATIONS IN THE AGE PATTERN OF INFANT AND CHILD MORTALITY WITH SPECIAL REFERENCE TO A CASE STUDY IN NGAYOKHEME (RURAL SENEGAL)

Abstract

Risks of death below age 5 years vary widely across human populations. This thesis investigates some environmental factors of--and sex differences in--the age pattern of mortality in infancy and childhood and analyzes the impact of this age pattern on Brass multipliers. The first chapter, based on a study of 456 national life tables, reviews variations in the pattern of mortality as it is affected by the level of development, climate and the sex composition of the population. An index of the pattern of infant and child mortality is, defined: RCIM, the ratio of child to infant mortality = (4 + e(,5) - e(,1))/(1 + e(,1) - e(,0)). Life expectancy is shown to be a major predictor of RCIM, with high mortality populations showing higher child mortality relative to infant mortality. Climate also has a strong impact on RCIM, with tropical areas having the highest ratio when controlling for life expectancy. Finally, females have a higher ratio than males as a result of their lower infant mortality. Chapter 2 investigates the relationship between the distribution of death by cause and regional pattern of mortality in 21 high-mortality populations. However this analysis is largely inconclusive because of the inaccuracy of data on causes of death. A second part of the dissertation (Chapters 3 and 4) is an indepth investigation of a rural area of Senegal (Ngayokheme). The pattern of mortality exhibits an outstanding tropical pattern, with extremely high child mortality. The major discrepancy between this and other patterns is the extremely high death rate at 18-35 months. Although this is the weaning period, there is no evidence that mortality is higher just after weaning. Mortality is also very high between 6 and 18 months which is related to a high prevalence from malaria. The study compares two periods (1963-1971 and 1972-1981) during which mortality below age 5 declines dramatically; however pattern of mortality is shown to remain the same. Comparison with other tropical areas is done. Sex differences in this area show specific features when compared to national life tables. Females have the same probability of dying below age 5 as males, but with a different structure: females have higher neonatal mortality, which is hypothesized to be related to low sex ratios at birth. They also have higher mortality from measles but lower mortality from respiratory diseases. . . . (Author\u27s abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UM