Effects of piped water supply on the incidence of diarrheal diseases in children in southern Thailand.

Simple piped water supply (PWS) is increasingly popular in rural areas of southern Thailand where diarrheal diseases are quite common. The current study was carried out in 1990 in the southern part of Thailand to determine whether the use of PWS could significantly reduce the incidence rate of diarrheal diseases among the children under two years of age. A dynamic cohort study started in January 1990 in seven Muslim villages where PWS was installed for some time and there was a mixture of PWS users and non-users in each village. The cohorts comprised 126 and 137 children using and not using PWS, respectively. They were followed up weekly for one year. The crude incidence rates of diarrhea episodes for children using and not using PWS were 2.54 (SE = 0.21) and 3.52 (SE = 0.18) episodes per child-year, respectively (p < 0.01). The number of diarrheal attacks in each week was modeled as a Poisson variate using a generalized estimating equation, adjusting for correlation within the child. The analysis was carried out for each village separately and meta-analysis was used to combine these analyses. The rate ratio of PWS, adjusted for concurrent age and season, food supplement and common cold, was 0.74 (95% CI = 0.59-0.93), indicating a statistically significant reduction of one quarter. However, the proportion of users decreased with time due to management failure. It was concluded that diarrheal disease in the study area was mild but the incidence rate was high. The effect of PWS on the incidence rate of diarrhea varied with locality.(ABSTRACT TRUNCATED AT 250 WORDS)