Environmental Engineering Reference
In-Depth Information
more watery bowel movements or at least one mucoid/bloody stool within 24 hr [19,
20]. We defined a new episode of diarrhea as the occurrence of diarrhea after a period
of 3 d symptom-free [20-22]. An episode of diarrhea was labeled “dysentery” if signs
of blood or mucus in the stool were recorded at any time. We also calculated the lon-
gitudinal prevalence (number of days a child suffered diarrhea divided by the number
of days of observation) because of its closer relation to severity, growth faltering, and
mortality than diarrhea incidence [19, 23]. Severe diarrhea (SD) was defined as the
occurrence of diarrhea on more than 10% of the observed days [24].
Data Collection and Field Staff
The primary outcome was measured by community-based field workers who were
recruited nearby and who lived one per community during data collection periods.
The field workers were extensively trained in interviewing and epidemiological ob-
servation techniques, data checking, recording, and in general approaches to com-
munity motivation. Community-based field workers were randomly rotated between
communities every 3 month. Child morbidity was reported by the closest caregiver
using the vernacular term “K'echalera,” which had been established previously to cor-
respond to the WHO definition of diarrhea [25]. Mothers or closest caretakers kept a
7-d morbidity diary recording daily any occurrence of diarrhea, fever, cough, and eye
irritations in study participants [25]. Community-based field workers visited house-
holds weekly to collect the health diaries, and supervisors revisited an average 7%
of homes. Discrepancies between supervisors and community-based field workers'
records were clarified during a joint home revisit. Child exposure risks were also as-
sessed by community-based staff interviewing mothers once during baseline and twice
during the 1-year follow-up.
Compliance with the SODIS method was measured using four different subjective
and objective indicators. Three of the indicators were assessed by fi eld staff inde-
pendent from the implementing NGO: (i) the number of SODIS-bottles exposed to
sunlight and, (ii) the number of bottles ready-to-drink in the living space, and (iii) the
personal judgment about families' user-status was provided by community-based fi eld
workers living among the families in the intervention arm. Judgment criteria for this
main compliance indicator study included observing regular SODIS practice and bot-
tles exposed to sun or ready to drink in the kitchen and being offered SODIS-treated
water upon request. The fourth SODIS-use indicator was based on self-reporting and
caregivers' knowledge of and attitudes toward the intervention that was assessed at the
beginning (i.e., 3 month after start of the intervention) and at the end of the 12-month
follow-up period.
Statistical Analysis
An intention-to-treat analysis was applied comparing the IR of diarrhea between chil-
dren <5 year in intervention and control communities. Diarrhea prevalence (PR) and
SD were additionally analyzed. Generalized linear mixed models (GLMMs) were fit-
ted to allow for the hierarchical structure of the study design (pair-matched clusters).
In contrast to our original trial protocol we selected the GLMM approach rather than
generalized estimating equations (GEEs) because recent publications indicated that
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