This study was an evaluation of the long-term health impact of household chlorination in the JSWF program in the Northwest and Artibonite Provinces of Haiti. Program records indicate that over the course of nearly eight years, positive chlorine residuals were detected for 70% of unannounced household visits (Turbes A, unpublished data). In this study, 56% of participants and 10% of controls had confirmed positive free chlorine residuals. It was expected that the proportion of participants with positive residuals would be higher than that of controls because they receive regular household visits and education. The reason for the lower percentage of participants whose water was positive for chlorine residual in the survey than in the program records can be partially explained by inconsistent use of chlorine by some participants or by selection bias in the program records if program technicians chose known frequent users for the unannounced programmatic visits to households.
In the intention-to-treat analysis, program participants had a 26% reduced odds of diarrhea compared with controls, and children < 5 years of age had a 59% reduced odds when we controlled for potential confounders. The effect of the program was likely stronger for children < 5 years of age because they are more susceptible to illness from waterborne organisms. Because participants who were not consistently using chlorine were included in the intention-to-treat analysis, this was a conservative estimate of the long-term health effects of this program. The treatment-on-treated analysis indicated larger diarrheal disease reductions when restricting the analysis to only the subset of participants who met more stringent criteria for use. The magnitude of the reduction in the odds of diarrhea was stronger for children < 5 years of age in participant households with positive chlorine residuals (treatment-on-treated OR = 0.30, 95% CI = 0.14–0.64) than for all children < 5 years of age in participant households (intention-to-treat OR = 0.43, 95% CI = 0.26–0.70).
In summary, in the intention-to-treat and treatment-on-treated analyses, program participation was strongly associated with reduced diarrheal disease, especially in children < 5 years of age. These findings indicate that the JSWF program has achieved long-term behavior change among program participants and resulted in improved health.
In this study, we found 10% of controls with positive free chlorine residuals in household stored drinking water. This finding is consistent with that of Rosa and Clasen,19
but could also be partially attributable to the community education being undertaken by the JSWF program, including posters, radio advertisements, and church announcements, which reach program participants and controls. When considering chlorination practiced by either participants or controls, rather than focusing on the health effects of the JSWF program specifically, we found that the odds of diarrhea among households with positive free chlorine residuals was 61% less (OR = 0.39, 95% CI = 0.26–0.57) than among households without positive chlorine residuals. Program participation did not have a significant effect (P
= 0.332 for all ages and P
= 0.202 for children < 5 years of age) when the analysis was limited to only households with positive free chlorine residuals, indicating that household chlorination resulted in improved health regardless of participation in the JSWF program, although this result could have been affected by selection bias.
The diarrheal prevalence reported in this study was approximately twice as high as in the most recent Demographic and Health Surveys. We hypothesize that the reasons for this are 1) the study area is the most remote, mountainous region of the Department and 2) displacement after the earthquake might have increased the number of family members living together in study households. Although reporting bias might have led to inflated diarrhea prevalence, we found a meaningful and statistically significant reduction in diarrhea among participant households.
The JSWF program has several aspects not found in many other household chlorination programs that potentially help make the program more effective. First, technicians conduct regular household visits and maintain records of purchase and household chlorine residuals, which can be used to establish whether households are consistent users. Second, the staff members running the program are all Haitian. Third, the components of the program, including the safe storage containers and the sodium hypochlorite, are produced locally. Fourth, the chlorine is sold at a slight profit margin so that program staff are fully paid with program income.4
One of the strengths of this evaluation was the incorporation of multiple indicators of program adoption, including self-reported use, program records, verified available chlorine supply in the household, and verified treatment based on free chlorine residual in household stored water. Our research design enabled us to complete a spectrum of analyses ranging from intention-to-treat, which provided a conservative result, to treatment-on-treated, which was less likely to underestimate the impact because it focused on participants who actually practiced chlorination, but potentially had more selection bias. Further research should have more stringent definitions of program participation so that controls who are using Gadyen Dlo are not included, and analyze subgroups of controls using the same categories as the subgroups of program participants in the treatment-on-treated analysis.
Lastly, the authors would like to place these results within the larger context of water treatment in Haiti after the earthquake and cholera emergencies. This research was planned before the earthquake occurred and the onset of cholera, although it was conducted between the two emergencies. The sole reason this location was selected for this research was because the JSWF program is the longest-running chlorination program with continuous monitoring and records known to the researchers. We did not modify our research protocol after the January 2010 earthquake because the research area was outside the affected area, although as mentioned previously, internally displaced persons did move into the area. However, one of the authors did conduct independent research on water treatment options distributed within the first eight weeks after the earthquake.20
DSI was the largest immediate water treatment responder to the earthquake; as of February 16, 2010, and DSI had reached 2,880 new families with safe storage containers and Aquatabs brand sodium dichloroisocyanurate chlorine tablets through a network of 165 CHW distributors in the Léogâne area, near the epicenter of the earthquake. This program built upon a replicate of the JSWF project in Léogâne, Haiti that existed before the earthquake. The DSI program in Léogâne had the highest effective use (56%) of all the water treatment options distributed in all four acute emergencies, including filters and chlorine options in Haiti. Effective use was measured as the percentage of targeted families using the distributed product to improve the microbiologic quality of their stored household drinking water to meet international guidelines. The lessons learned in the JSWF project, and replicated in the Léogâne project before the earthquake, directly led to successful emergency implementation because unlike other programs, DSI was able to target households with contaminated water and provide them with an effective water treatment option that they were familiar with in a timely manner.
Additionally, between the time of this evaluation and the subsequent cholera outbreak in Haiti in October 2010, the program has undergone a four-fold expansion to approximately 16,000 households. Further research will be needed to assess whether the program is able to maintain the characteristics that have made it so effective in its original form as it expands to a much larger population as part of emergency response efforts.
There were four main limitations in this study. First, the JSWF program members consciously made a decision to enroll in the program, and thus enrollment was not random. Therefore, there may have been unobservable differences between participants and controls not accounted for in the regression analysis that were inherent to why JSWF participants enrolled, and which could have contributed to differences in diarrhea rates between the two groups. Second, 39 controls (10.0%) stated at survey outset they were not program participants, but contradicted themselves later in the survey by self-reporting that they currently used Gadyen Dlo. In the future, evaluations should attempt to more strictly confirm non-participation, although this can be difficult in the field. Third, there was an abnormally high rate of missing data for the free chlorine residual testing (12.5% of participants and 38.4% of controls), which we suspect was caused by enumerator neglect and not participant refusal, because one of the authors has conducted more than 1,000 free chlorine residual tests in household surveys in rural Haiti and showed a refusal rate < 1% rate for free chlorine residual testing. This might have led to selection bias. Fourth, we relied on self-reported diarrhea as our outcome measure. A subset of households might have over-reported water treatment and under-reported or over-reported diarrhea because of social desirability or courtesy bias, which would lead to spurious evidence of program health effects. However, these concerns are mitigated, but not fully alleviated, by the facts that: 1) JSWF program members closely resembled control households on most observable characteristics for which we have data; 2) enumerators were not associated with the JSWF program; 3) the JSWF program was not identified in the survey; and 4) strong correlations were observed between diarrheal disease reductions and more stringent indicators of use, including bottle sales and chlorine residual presence, based on independent program records.
This study is one of the first to examine the long-term health impact of household chlorination programs. The health impact of the JSWF program among households who had participated in the program for an average of more than four years is consistent with other efficacy studies of household chlorination for shorter time periods. A meta-analysis of household chlorination studies, in which only four studies had a duration of at least one year, found that the risk of diarrhea in children < 5 years of age was reduced by 40%.19
Another meta-analysis in which the longest study period considered was 87 weeks (1.7 years) but the median length was 20 weeks, found a 29% reduction in the risk of childhood diarrhea.12
The JSWF program, which had a 59% reduced odds of diarrhea in children < 5 years of age after more than four years of participation demonstrates that the health impact of household chlorination programs does not necessarily decrease over time when consistent chlorine use is maintained.
After nearly eight years of operation, the JSWF program has achieved long-term behavior change and significant diarrheal disease reduction among program participants who live within three hours of the clinic. Using both conservative intention-to-treat analysis that assessed JSWF programmatic impact among all enrolled households and treatment-on-treated analysis restricted to participants with stricter indicators of adoption, we found that household chlorination can be an effective long-term water treatment strategy. In the JSWF program, participants continue to make small investments to improve their water quality in the home and have better health outcomes as a result. The findings may help inform the development of other programs by demonstrating a working household chlorination model in which chlorine sales and use have been consistently recorded and diarrheal disease reduction has been evaluated.