Child mortality is an appropriate indicator for measuring the impact of interventions on health and for monitoring the health status of populations (1, 2, 3). Although widely used as a primary objective for health and development programmes In developing countries, estimations of mortality patterns are often impossible to obtain, and therefore rarely included in project evaluations. Moreover, few studies have assessed the impact of environmental changes on the health status of populations.
Bangladesh is mostly a low-lying deltaic flood plain at the confluence of three of the world's major rivers. Between July and September, these rivers frequently overflow their banks and inundate about a third of the land surface, depositing silt on the flood plains and thus maintaining soil fertility (4). Besides the "normal" seasonal floods, the country regularly experiences severe floods and cyclones that cause widespread damage to crops and property (5, 6). Flood control projects have been undertaken in many areas exposed to the floods. These projects protect low-lying land through the construction of earthen embankments, usually in combination with irrigation and drainage components. The aims are to increase agricultural production by year-round cultivation of high-yielding varieties of rice using modern methods of cultivation and to protect the beneficiaries against extensive floods (7). However, such projects are criticized for many adverse effects (8), for example:
-- restricting the seasonal deposit of sediment reduces soil fertility and leads to an intensive use of fertilizers and to further environmental degradation;
-- the absence of "flushing action" by receding flood water results in contamination of surface water by fertilizers and agrochemicals;
-- small fisheries are destroyed and new farming technologies are introduced which benefit wealthy farmers at the expense of poorer ones; and
-- many farmers lose their land by the transfer of cultivated land to embankment infrastructure development.
This study analysed child mortality (for children 0-4-years of age) in the Matlab study area to assess the impact of a flood control project on the health status of the beneficiaries. A secondary objective was to monitor the achievements of the maternal and child health programme by controlling the effect of the embankment.
Materials and methods
Matlab is a field study area of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), 55 km south-east of Dhaka. The area is a low-lying deltaic plain, intersected by numerous tidal rivers and canals. During the monsoon, almost all the land is flooded, with only clusters of homes built on earthen mounds remaining above the water level. As part of the national flood control and irrigation programme, a US$ 33 million project was carried out in the district near the confluence of two major rivers -- the Meghna and the Dhonagoda (7). The 60-km long earth embankment was expected to provide flood protection to a gross area of 17000 hectares, including part of the Matlab study area and about 31% of its population (Fig. 1). The embankment was completed in July 1987, but was breached in August the same year and again in August 1988. The total population in the Matlab study area is about 200 000, with a density of 1134 inhabitants per [km.sup.2], one of the highest in the rural world. About a third of this population lives inside the embankment. Muslims represent 85% of the population, with the rest being Hindus.
[Figure 1 ILLUSTRATION OMITTED]
Since 1963, six cholera vaccine trials have been conducted in Matlab, and a demographic surveillance system has been in operation since 1966, consisting of periodic censuses along with a continuous household registration of all vital events such as birth, death, migration and marriage. Female community workers visit each household twice a month and report all deaths to a trained health assistant. …