The decline of mortality in Ceylon and the demographic effects of malaria control

Abstract

This paper is a reappraisal of the decline of mortality in Ceylon with special reference to the effects of malaria control after 1945. Prior to the Second World War there was an association between the level of mortality and the prevalence of malaria by district in Ceylon. It is shown by the use of a regression model and by geographical analysis that this inter-district differential in mortality can be largely, if not exclusively, ascribed to the inter-district variation in malaria prevalence. Also, the distribution of health services and variations in the levels of nutrition cannot explain the mortality differentials in pre-war Ceylon. There was a rapid decline in mortality during the post-war period which was associated with an island-wide malaria control campaign, an extension of the health services, an improvement in nutrition and some economic development. During this period the previous inter-district differentials of mortality were eliminated and death rates became homogeneous throughout Ceylon. From a regression model correlating the proportional decline in district mortality with the prevalence of malaria, it is estimated that the malaria control programme contributed approximately 23 per cent or 2·3 per thousand to the decline in the national crude death rate, and malaria control was the major factor responsible for the elimination of the pre-war variation in district mortality levels. Similar effects of malaria control on mortality have been observed in a number of countries. By applying a multiple regression model it is shown that changes in the distribution of health services cannot account for the excessive fall of mortality observed in the more malarious districts, and that improvements in the health services, nutrition, and economic development contributed individually indeterminate amounts to the overall mortality decline. The conclusions drawn from the present analysis are critically compared with the results of previous studies on the mortality decline in Ceylon.