Data collected in the late 1980s from eight countries in Sub-Saharan Africa
(Burundi, Ghana, Togo, and Uganda), Asia/North Africa (Sri Lanka and Morocco),
and the Americas (Bolivia and Guatemala) were combined and analyzed to test
whether incremental health effects regarding diarrhea and nutritional status
result from incremental improvements in water and sanitation conditions.
Rural (n = 11,992) and urban (n = 4,888) samples were analyzed separately.
Optimal (i.e., on the premises) and intermediate (improved public water)
water supplies were compared with unimproved water conditions. Optimal
(flush toilets or water-seal-latrines) and intermediate (latrines) sanitation
levels were compared with unimproved sanitation. Nationally representative
(random) samples of ever-married women age 15-49 years, with or without
children, were interviewed in all countries, and children aged 3-36 months
with available weight and height data were included in the analyses. Multiple
linear regression controlled for household, maternal, and child-level
variables; in addition, dummy variables were included for each country.
Improvements in sanitation resulted in less diarrhea and in taller and heavier
children with each of the three levels of water supply. Incremental benefits
in sanitation were associated with less diarrhea and with additional increases
in the weights and heights of children. The effects of improved sanitation
were greater among urban dwellers than among rural dwellers. Health benefits
from improved water were less pronounced than those for sanitation. Benefits
from improved water occurred only when sanitation was improved and only when
optimal water was present. These findings suggest that public health
intervention should balance epidemiologic data with the cost of services and
the demand for water. There should be efforts to develop compatible technologies
so that incremental improvements in service can be made.