Context Washing hands with soap prevents diarrhea, but children at the highest
risk of death from diarrhea are younger than 1 year, too young to wash their
own hands. Previous studies lacked sufficient power to assess the impact of
household handwashing on diarrhea in infants.
Objective To evaluate the effect of promoting household handwashing with soap
among children at the highest risk of death from diarrhea.
Design, Setting, and Participants A cluster randomized controlled trial of 36 low-income neighborhoods
in urban squatter settlements in Karachi, Pakistan. Field workers visited
participating households at least weekly from April 15, 2002, to April 5,
2003. Eligible households located in the study area had at least 2 children
younger than 15 years, at least 1 of whom was younger than 5 years.
Interventions Weekly visits in 25 neighborhoods to promote handwashing with soap after
defecation and before preparing food, eating, and feeding a child. Within
intervention neighborhoods, 300 households (1523 children) received a regular
supply of antibacterial soap and 300 households (1640 children) received plain
soap. Eleven neighborhoods (306 households and 1528 children) comprised the
Main Outcome Measure Incidence density of diarrhea among children, defined as the number
of diarrheal episodes per 100 person-weeks of observation.
Results Children younger than 15 years living in households that received handwashing
promotion and plain soap had a 53% lower incidence of diarrhea (95% confidence
interval [CI], –65% to –41%) compared with children living in
control neighborhoods. Infants living in households that received handwashing
promotion and plain soap had 39% fewer days with diarrhea (95% CI, –61%
to –16%) vs infants living in control neighborhoods. Severely malnourished
children (weight for age z score, <–3.0)
younger than 5 years living in households that received handwashing promotion
and plain soap had 42% fewer days with diarrhea (95% CI, –69% to –16%)
vs severely malnourished children in the control group. Similar reductions
in diarrhea were observed among children living in households receiving antibacterial
Conclusion In a setting in which diarrhea is a leading cause of child death, improvement
in handwashing in the household reduced the incidence of diarrhea among children
at high risk of death from diarrhea.