1 Institute of Public Health, Federal University of Bahia, Salvador, Brazil.
2 London School of Hygiene and Tropical Medicine, London, United Kingdom.
3 Department of Social Anthropology and American and African History, University of Barcelona, Barcelona, Spain.
Received for publication March 1, 2002; accepted for publication December 10, 2002.
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ABSTRACT |
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behavior; child; diarrhea; house calls; hygiene; risk factors; sanitation; water supply
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INTRODUCTION |
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It is now widely accepted that water supplies and sanitation, though necessary for the prevention of diarrheal diseases in young children, are not sufficient (5) unless they are accompanied by changes in domestic hygiene behavior (6). There is also a growing realization that questionnaire surveys are inadequate for studying behavior with regard to such a stigmatized topic as hygiene. Wide divergence has been found between what people say they do and what they are seen to do when structured observation is used (79). People also demonstrate reactivity, changing their behavior to present a more favorable image when they know they are under observation (10, 11). Nevertheless, structured observation seems to be less subject to bias than other quantitative approaches to assessing behavior (12).
We conducted an epidemiologic study of the relation between diarrhea and hygiene behavior, using structured observations collected over a 1-year period at very modest cost. Observations were made opportunistically during brief twice-weekly household visits whose main purpose was to record episodes of diarrhea in young children. To test the usefulness of this approach, we evaluated the role of sanitation facilities and hygiene behavior in diarrheal disease determination.
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MATERIALS AND METHODS |
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Observation schedule
Twenty-three specific behaviors were selected as being likely to be observed during a home visit of a few minutes and also to carry a risk of diarrheal disease transmission. The experience of the fieldwork team, including the interviewers comments during the preliminary phase of the fieldwork and the observations of anthropologists, and the findings of previous studies (1417) were used as a basis for this selection. The list included behavior by the child as well as by the mother or other caretaker in the family. These behaviors are listed in table 1.
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This arrangement of the observation recording schedule with explicit alternatives also helped with data quality assurance; it would be most unlikely that both positive and negative variants of a behavior would be observed during the brief duration of a visit. Marking "no" against an action indicated clearly that it had not been observed, in either a positive or a negative form.
Data regarding a number of environmental variables, including the presence or absence of piped water and sanitation in the household and of any open sewage channels in the vicinity (i.e., visible from the house) were collected by questionnaire and observation at the beginning of the fieldwork. "Adequate excreta disposal" was defined to include toilets discharging to sewers, drains, and septic tanks.
Field-workers and implementation
The 15 field-workers employed for the work had all completed a secondary education. They were selected on the basis of their performance in a role-playing exercise simulating the conditions of the home visits. Their training lasted 10 days, including the pilot-testing of the observation schedule in the field.
The observations were made twice weekly during the home follow-up visits from the 18th week to the 70th week of the epidemiologic study, that is, from March 30, 1998, to April 29, 1999. The data covered 942 of the 1,153 children in the main studya total of approximately 90,000 home visits.
Data analysis
For the analysis, not all of the behaviors listed in table 1 were considered. Giving priority to those referring directly to the protection or exposure of the index child, we dropped some of the behaviors because they referred to mothers/caretakers behaviors that had no effect on child diarrhea (for instance, the mothers drinking tap water or sitting on the ground when eating) or because they would not be expected from a small child (adding chlorine to the water or washing vegetables). Of the remaining behaviors, a few were combined; thus, for the analysis, 33 possibilities were considered. The observations "bathes before breakfast" and "bathes before lunch" were used as proxies for "washes hands before eating," since this latter behavior was rarely recorded directly.
The 33 options were divided into 15 "negative" behaviors likely to favor fecal-oral disease transmission and 18 "positive" practices that were more likely to help prevent it (table 2). If a given behavior by the child or the caretaker was observed one or more times, one point was added to the childs positive score. Similarly, if a given negative behavior was seen at least once, one point was added to the negative score of that child.
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For a specific study of behaviors involving use of water for hygiene, a similar categorization was performed using a selection of 15 positive behaviors and 11 negative behaviors. Of the positive behaviors, all but the last three were used (table 2). Of the negative behaviors, the last four were dropped. The total scores were standardized as before, dividing by 15 and 11, respectively.
Incidence of diarrheathat is, the number of episodes of diarrhea per child-yearand longitudinal prevalencethat is, the fraction of days of follow-up with diarrhea, which has been shown (18) to be more closely associated than incidence with long-term health effects such as weight gain and mortalitywere used as the outcome measures.
Data analysis was performed using Stata software (Stata Corporation, College Station, Texas). Poisson regression analysis was used to estimate the effect of behaviors on the longitudinal prevalence and incidence of diarrhea, and the 2 test was used for significance testing in the contingency tables.
Ethics
Informed consent was obtained from all study households. Ethical approval for the study was given by the Ethics Review Board of the Federal University of Bahia.
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RESULTS |
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Table 3 shows the association between hygiene behavior and the prevalence and incidence of diarrheal disease in the study children. Among children for whom mainly positive hygiene behavior was recorded, the prevalence of diarrhea was 6.4 days per child-year, while it was 14.2 days per child-year in children with mainly negative scores. Children with no observations experienced an intermediate prevalence. The difference between the positive and negative groups was highly significant, corresponding to a relative risk of 2.22 (95 percent confidence interval: 1.75, 2.81). After data were controlled for seven potentially confounding factors, including the presence of piped water and a toilet in the house, the relative risk was reduced to 1.95 (95 percent confidence interval: 1.54, 2.47) but was still highly significant. The incidence was 2.4 episodes per child-year among children with mainly positive scores and 4.1 episodes per child-year among children with mainly negative scores. This yielded a highly significant unadjusted relative risk of 1.70 (95 percent confidence interval: 1.44, 2.01), which was reduced to 1.61 (95 percent confidence interval: 1.36, 1.90) but remained significant after we controlled for the same potentially confounding factors as for prevalence.
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DISCUSSION |
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In this study, structured observations were made as a part of biweekly visits to households for collection of data on childrens diarrhea in the previous 3 or 4 days. Each visit took only a few minutes and was used as an opportunity for the visitor to observe and record hygiene behaviors by the child and the mother/caretaker. The results presented here are indicative that there would be advantages in an approach to structured observation by which snapshots taken over many months could be pooled to obtain a score representing a persons characteristic standard of hygiene behavior over the long term. Through systematic recording of behaviors by observers, investigators using this strategy would avoid the well-known limitations of recall methods that rely on questionnaires. This method also has advantages over either spot or in-depth observations, being as unobtrusive and low cost as the former but potentially more reliable than both because of its repetition over an extended period of time. To us, the most attractive feature of such a strategy is that information on behavior, which is generally treated with qualitative tools, can be turned into variables for quantitative epidemiologic analysis, allowing the coupling of behavioral observations and epidemiologic data, which, with few exceptions (15, 17, 19, 21), is rarely encountered in the relevant literature on diarrhea.
The strength of the association between hygienic behavior and lower diarrhea morbidity is suggestive of the validity of the observational data and hence of the feasibility of this strategy of collecting meaningful information about hygiene behavior using a low-cost opportunistic approach. The intermediate diarrhea prevalence in the intermediate behavior group, for most of whom no behavioral observations had been made, supports the assertion that this group was not a biased selection from the population, with particularly positive or negative hygiene behavior.
The data presented here are indicative of the important role of hygiene behavior, in addition to the well-known importance of a water supply and sanitation facilities in the household, in the causation and prevention of diarrheal disease. The significant relative risk of diarrhea, which was associated with mainly negative behavior as compared with positive, was, at 2.2 for longitudinal prevalence, the highest in the univariate analysis of 12 environmental determinants of diarrhea (Strina, unpublished data).
A remarkable finding is the significant association between a positive hygiene score and the presence of adequate excreta disposal facilities in the household (table 4). It does not seem likely that the presence of a toilet was the cause of the difference in behavior, because none of the specific behaviors contributing to the score were concerned with excreta disposal practices. Nevertheless, there could be a degree of such a causal link if piped water led people to practice positive hygiene behaviors using water and if piped water were associated, as it is in most settings, with the presence of a toilet. In order to establish whether this could be so, we carried out a similar analysis with the list of behaviors restricted to those associated with water use. However, no association between a positive hygiene behavior score and a water supply was observed when the limited list of behaviors was used (table 5).
We concluded that the causality runs the other way; that is, it would seem that families predisposed to have adequate sanitation in their homes have a measurably better awareness of hygiene, expressed in their behavior, than those which do not. Moreover, such differences in behavior are reflected in the prevalence of diarrhea among their children.
No such association with behavior was found with the presence of open sewage channels near the household, a characteristic of neighborhoods where community sanitation infrastructure is lacking and a factor that is beyond the control of an individual household. This suggests that the difference is associated with a familys individual predisposition to install and use a toilet, rather than a characteristic of the neighborhood in which they live.
Similar associations between sanitary facilities and hygiene behavior have been found elsewhere. Curtis et al. (22) found that households in Bobo Dioulasso, Burkina Faso, which had piped water were more likely to keep their yards free of visible contamination with excreta. Hoque et al. (23) found in Bangladesh that the hand-washing technique used in households owning a latrine was more thorough than that in households which did not. In both of these cases, the nature of the behavior was such that it could not be attributed to the facilitating effect of the water supply or toilet.
The association of adequate sanitation and hygienic behavior casts doubt on a substantial body of literature in which the health impact of sanitation is assessed by observational studies (in the sense of nonintervention studies) of diarrheal disease (24, 25). The best such studies have used multivariate analysis in an effort to control for confounding by socioeconomic status, but there are limits to the degree to which such methods can control for all possible confounding factors, particularly when the data relate to self-selected exposure groups (26) and the relative risks involved are quite small (27). If families that install toilets behave in more hygienic ways anyway, then the fact that such households have less diarrhea is attributable not to the toilet but to the characteristics of the household which led them to install it.
Fortunately, this does not call into question the conclusion that sanitation offers health benefits in Salvador, because other research carried out in the city has shown that the association of high diarrhea rates with a lack of sanitation is stronger when whole neighborhoods are compared than when the data are analyzed by individual household (28; Strina, unpublished data).
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ACKNOWLEDGMENTS |
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The authors thank the fieldwork team, especially their supervisor, J. C. Goes.
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NOTES |
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REFERENCES |
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