Combining drinking water treatment and hand washing fordiarrhoea prevention, a cluster randomised controlled trialStephen P. Luby1, Mubina Agboatwalla2, John Painter1, Arshad Altaf3, Ward Billhimer4, Bruce Keswick4and Robert M. Hoekstra11 Division of Bacterial and Mycotic Diseases, National Centers for Infectious Diseases, Centers for Disease Control & Prevention,Atlanta, Georgia, USA2 Health Oriented Preventive Education, Karachi, Pakistan3 Community Health Sciences, Aga Khan University, Karachi, Pakistan4 The Procter and Gamble Company, Cincinnati, Ohio, USASummary objectives To evaluate the effectiveness of point of use water treatment with flocculent-disinfectant onreducing diarrhoea and the additional benefit of promoting hand washing with soap.methods The study was conducted in squatter settlements of Karachi, Pakistan, where diarrhoea is aleading cause of childhood death. Interventions were randomly assigned to 47 neighbourhoods.Households in 10 neighbourhoods received diluted bleach and a water vessel; nine neighbourhoodsreceived soap and were encouraged to wash hands; nine neighbourhoods received flocculent-disinfectantwater treatment and a water vessel; 10 neighbourhoods received disinfectant-disinfectant water treat-ment and soap and were encouraged to wash hands; and nine neighbourhoods were followed as con-trols. Field workers visited households at least once a week from April to December 2003 to promote useof the interventions and to collect data on diarrhoea.results Study participants in control neighbourhoods had diarrhoea on 5.2% of days. Comparedto controls, participants living in intervention neighbourhoods had a lower prevalence of diarrhoea:55% (95% CI 17%, 80%) lower in bleach and water vessel neighbourhoods, 51% (95% CI 12%, 76%)lower in hand washing promotion with soap neighbourhoods, 64% lower (95% CI 29%, 90%)in disinfectant-disinfectant neighbourhoods, and 55% (95% CI 18%, 80%) lower in disinfectant-disinfectant plus hand washing with soap neighbourhoods.conclusions With an intense community-based intervention and supplies provided free of cost, eachof the home-based interventions significantly reduced diarrhoea. There was no benefit by combininghand washing promotion with water treatment.keywords diarrhoea, water, soaps, disinfection, sodium hypochlorite, randomised controlled trialIntroductionDiarrhoea is a leading cause of childhood death globally(WHO 1999). When introduced separately, both point-of-use drinking water treatment and hand washing with soapdecrease the frequency of childhood diarrhoea (Mintz et al.2001; Curtis & Cairncross 2003). Recent meta-analysesestimate a mean 47% reduction in diarrhoea with handwashing with soap and a mean 35% reduction with pointof use water treatment (Curtis & Cairncross 2003; Fewtrellet al. 2005). If either of these interventions was activelypromoted by a public health organisation, the marginalcost of promoting the second one would be reduced.However, we are unaware of any studies evaluating thecombined effectiveness of hand washing promotion withpoint-of-use water treatment.In Pakistan, diarrhoea is a leading cause of death,especially in the squatter settlements of its large cities(Marsh et al. 1995; Khan et al. 1993). Previous interven-tion studies in squatter settlements in Pakistan havedemonstrated that both point-of-use drinking water treat-ment with sodium hypochlorite and hand washing withsoap reduced diarrhoea (Luby et al. 2004a, b). Weintroduced a new flocculent-disinfectant for home watertreatment as part of a neighbourhood-based intervention.We evaluated its effect in reducing diarrhoea and theadded effect of including hand washing promotion withsoap.Tropical Medicine and International Health doi:10.1111/j.1365-3156.2006.01592.xvolume 11 no 4 pp 479–489 april 2006ª 2006 Blackwell Publishing Ltd 479MethodsSettingThis study was conducted in adjoining multi-ethnicsquatter settlements in central Karachi—Bhittaiabad, BilalColony, Mujahid Colony, Manzoor Colony and ZiaColony. The field work was done by Health OrientedPreventive Education (HOPE), a local non-governmentalorganisation that operates health clinics and undertakescommunity-based health and development initiatives in thearea.DesignThe study was a cluster randomised controlled trial.Randomisation and intervention assignment was made atthe neighbourhood level, because important components ofthe efforts to encourage adoption and regular use of theintervention occurred at this level. These included formalmeetings and presentations by study personnel to com-munity leaders and community members, lane meetingswith community residents, as well as the normal discus-sions that neighbours had with each other about theinterventions when no study personnel were present.Study groupsField workers identified communities that typicallyreceived at least one hour of running water twice weekly,and had not received soap or water treatment in a previousstudy with HOPE. Within these communities the studyteam identified barriers, for example a commercial street orindustrial zone that separated groups of households into 49identifiable clusters of between 54 and 245 households.Within the clusters field workers approached each house-hold. If the female or male head of household confirmedthat they had at least one child under the age of 5 yearsliving in the household and if they provided informedconsent, the field workers administered a baseline ques-tionnaire. Ultimately, they identified 49 clusters withbetween 16 and 37 eligible, consented households percluster.The 49 clusters were listed in the order that they hadbeen identified. Using a spreadsheet, the five study groups(bleach water treatment, hand washing promotion withsoap, flocculent-disinfectant water treatment, flocculent-disinfectant plus hand washing promotion with soap andcontrol) were assigned a computer generated randomnumber. The five study groups were ordered according totheir random number, and this order was consecutively andrepetitively applied to the list of the 49 clusters. Each studygroup continued to have clusters assigned until just over260 households were assigned to the group. Any additionalclusters that would have been assigned to that group byconsecutive assignment, but would have been more thannecessary to encompass 260 households, were left unas-signed. Ultimately 47 clusters and 1340 households wereassigned to the five study groups (Figure 1).Field workersField workers, recruited from
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