Conceived and designed the experiments: KZ BS JK JU. Performed the experiments: KZ BS. Analyzed the data: KZ BS JK JU.
The authors have declared that no competing interests exist.
A systematic review and meta-analysis by Kathrin Ziegelbauer and colleagues finds that sanitation is associated with a reduced risk of transmission of helminthiases to humans.
In countries of high endemicity of the soil-transmitted helminth parasites
We conducted a systematic review and meta-analysis to assess the effect of sanitation (i.e., access and use of facilities for the safe disposal of human urine and feces) on infection with soil-transmitted helminths. PubMed, Embase, ISI Web of Science, and the World Health Organization Library Database were searched without language restrictions and year of publication (search performed until December 31, 2010). Bibliographies of identified articles were hand-searched. All types of studies reporting data on sanitation availability (i.e., having access at own household or living in close proximity to sanitation facility), or usage, and soil-transmitted helminth infections at the individual level were considered. Reported odds ratios (ORs) of the protective effect of sanitation on soil-transmitted helminth infections were extracted from the papers or calculated from reported numbers. The quality of published studies was assessed with a panel of criteria developed by the authors. Random effects meta-analyses were used to account for observed heterogeneity. Thirty-six publications, consisting of 39 datasets, met our inclusion criteria. Availability of sanitation facilities was associated with significant protection against infection with soil-transmitted helminths (OR = 0.46 to 0.58). Regarding the use of sanitation, ORs of 0.54 (95% confidence interval [CI] 0.28–1.02), 0.63 (95% CI 0.37–1.05), and 0.78 (95% CI 0.60–1.00) were determined for
Despite a number of limitations (e.g., most studies used a cross-sectional design and were of low quality, with potential biases and considerable heterogeneity), our results reveal that sanitation is associated with a reduced risk of transmission of helminthiases to humans. Access to improved sanitation should be prioritized alongside preventive chemotherapy and health education to achieve a durable reduction of the burden of helminthiases.
Worldwide, more than a billion people are infected with soil-transmitted helminths, parasitic worms that live in the human intestine (gut). Roundworm, whipworm, and hookworm infections mainly occur in tropical and subtropical regions and are most common in developing countries, where personal hygiene is poor, there is insufficient access to clean water, and sanitation (disposal of human feces and urine) is inadequate or absent. Because infected individuals excrete helminth eggs in their feces, in regions where people regularly defecate in the open, the soil becomes contaminated with eggs. People pick up roundworm or whipworm infections when they ingest these eggs after they have matured in the environment by eating raw, unwashed vegetables or by not washing their hands after handling contaminated soil (a common transmission route for children). In the case of hookworm, the immature, infective stages of the worms, which hatch in the soil, can penetrate human skin, and people usually become infected by walking barefoot on contaminated soil. Mild infections with soil-transmitted helminths rarely have symptoms, but severe infections can cause abdominal pain and diarrhea, weakness, and malnutrition that can impair physical and mental development. Many soil-transmitted helminth infections can be safely and effectively treated with anthelmintic drugs, but there is rapid reinfection after successful treatment.
In 2001, the World Health Organization endorsed preventative chemotherapy as the global strategy to control soil-transmitted helminthiasis. The key component of this strategy is regular administration of anthelmintic drugs to at-risk groups—children, women of childbearing age, and adults in high-risk occupations such as nightsoil reuse and farming. Although this strategy reduces illness caused by soil-transmitted helminths, it does not prevent rapid reinfection. To interrupt transmission and to achieve local elimination of helminthiasis, integrated control approaches that include access to sanitation and other complementary interventions of a primary prevention nature are needed. In this systematic review and meta-analysis, the researchers investigate whether the availability and/or use of sanitation facilities (latrines or toilets) lowers the risk of soil-transmitted helminth infections. A systematic review uses predefined criteria to identify all the research on a given topic; a meta-analysis is a statistical method that combines the results of several studies.
The researchers identified 36 publications that included data on sanitation availability and/or use and the number of people in the study population infected with one or more of three types of soil-transmitted helminths. Meta-analysis of the data from these publications indicates that, compared to people with no access to sanitation facilities, people with access to sanitation facilities were half as likely to be infected with soil-transmitted helminths. Specifically, the odds ratios (ORs; chances) of infection with soil-transmitted helminths among people with access to latrines compared to people without access to latrines were 0.46, 0.56, and 0.58 for roundworm, whipworm, and hookworm, respectively; for all three helminths combined, the OR was 0.49. Use of (as opposed to access to) sanitation facilities also protected against soil-transmitted helminth infection (ORs of 0.78, 0.54, and 0.63 for roundworm, whipworm, and hookworm infections, respectively). Finally, combining the data for both access and use, people who either had or used a latrine were half as likely to be infected with a soil-transmitted helminth as people who neither had or used a latrine (OR 0.51).
The studies included in this systematic review and meta-analysis have several shortcomings. For example, most were cross-sectional surveys—studies that examined the effect of the availability/use of sanitation on helminth infections in a population at a single time point. Given this study design, people who had latrines may have shared other characteristics that were actually responsible for the observed reductions in the risk of soil-transmitted helminth infections. Moreover, the data on latrine availability and use was derived from questionnaires and may, therefore, be inaccurate because people are often ashamed to admit that they defecate outside. Finally, the overall quality of the included studies was low. Nevertheless, these findings confirm that providing access to, and promoting use of, sanitation facilities is an effective control measure for soil-transmitted helminthiasis. Thus, there should be more emphasis on expanding access to adequate sanitation in control strategies for soil-transmitted helminths. This change in emphasis would reinforce the effects of preventative chemotherapy and ongoing health education on helminthiasis, in an economic, sustainability, and public health sense. Importantly, it would also improve the control of other neglected tropical diseases such as schistosomiasis and trachoma and would reduce the incidence of diarrhea, and thus child mortality, in developing countries.
Please access these websites via the online version of this summary at
The US National Institute of Allergy and Infectious Disease provides information on
The US Centers for Disease Control and Prevention also provides detailed information on
The World Health Organization provides information on
The
Two international programs promoting water sanitation are the
The
An estimated 4.5 billion people are at risk of infection with one of the three common soil-transmitted helminths, namely, the roundworm (
In 2001, the World Health Organization endorsed preventive chemotherapy as the global strategy to control morbidity due to soil-transmitted helminthiasis and schistosomiasis
We were interested in the evidence regarding sanitation (i.e., access to, and use of, facilities for the safe disposal of human urine and feces) and its effects on infection of humans with soil-transmitted helminths. A systematic review and meta-analysis were carried out to determine whether the availability and/or use of sanitation facilities was associated with a reduced risk of infection with soil-transmitted helminths from single or multiple species.
We performed a systematic review and meta-analysis adhering to the MOOSE guidelines for reporting meta-analyses of observational studies (see
Additionally, two previous general reviews pertaining to water and sanitation and parasitic worm infections were examined for relevant references
However, most intervention studies were excluded, because of specific aspects of the design, setting, and the complexity of interventions (e.g., multiple control measures) where the studies were implemented. Indeed, it is difficult to compare intervention studies carried out over different time frames and to distinguish studies that used single or multiple interventions (sanitation plus water supply, preventive chemotherapy, and health education)
In the first step, studies identified in our computer-aided search that failed to meet at least one inclusion criterion after scrutinizing the title and, if available, the abstract, were excluded. In the second step, two reviewers (K. Z. and B. S.) independently examined the full text of potentially relevant articles using a standard protocol developed by the authors (see
Relevant data, including a brief description of the study (e.g., study design, setting, year, and sample size), the primary research question pursued by the study, details of the study population (e.g., all age groups, school-aged children only, or other special groups) and the selection of study population (e.g., random selection), specificities on sanitation facilities (i.e., availability or use), and the helminth species investigated were extracted from all eligible studies by K. Z. using a standard protocol and independently cross-checked by B. S.
The reported odds ratios (ORs) served as effect measures. For studies that did not report ORs, these were calculated from 2×2 contingency tables of sanitation facility (availability or use) and infection status with soil-transmitted helminths, compared to the infection status of those who do not have access to, or use, sanitation facilities. Whenever possible, reported ORs were used; if both adjusted and unadjusted ORs were reported, we considered unadjusted ORs. Studies reporting effect measures for more than one helminth species were considered, and relevant results were fed into the respective meta-analyses.
Inspired by the GRADE methodology
All studies were pooled in the meta-analyses and stratified by soil-transmitted helminth species (overall OR). Furthermore, we carried out separate meta-analyses for
ORs were calculated for specific soil-transmitted helminths by comparing prevalence rates among those individuals having access to, or using, sanitation and those without, or not using, facilities employing the “metan” code of Stata version 10 (StataCorp). StatsDirect version 2.4.5 (StatsDirect) was used for meta-analyses, performed for
Our computer-aided search yielded 2,537 publications (
Overall, 36 publications were identified, containing 39 datasets (A). Number of hits (B) and ultimate identification of relevant publications (C) are also shown, for three different electronic databases. STH, soil-transmitted helminths. aMultiple exclusion criteria possible.
Twenty-five publications investigated the effect of sanitation availability on infection with soil-transmitted helminths, whereas the remaining 11 articles focused on the use of sanitation and infection with soil-transmitted helminths. From the 36 publications, 16 focused on Asia
Of note, multiple studies dating back to the early decades of the last century from the southern part of the United States, Panama, and elsewhere also reported an impact of sanitation (often in combination with chemotherapy and other control measures) on soil-transmitted helminth infections
Most of the publications identified were descriptive cross-sectional surveys, assessing single or multiple risk factors for infection with soil-transmitted helminths (
Reference | Study Design and Setting | Year | Study Population (Selection) | Availability (A) or Use (U) of Sanitation | Soil-Transmitted Helminth Species | Data Obtained | Diagnostic Approach (D) | Sanitation (S) | Other Strengths and Limitations (O) | Points | |||
Method | Quality Control | Toilet Status Assessment Method | Spot Checks | D/S/O | Total | ||||||||
Al-Mekhlafi et al. |
Descriptive study in one school in Malaysia | 2006 | Sc (random) | A | A.l. | OR (MVA) | K-K (Hw: H-M) | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Asaolu et al. |
Descriptive study in two communities in Nigeria | 1998 | PSc (all) | A | A.l. | 2×2 table | Mod. K-K | n.s. | Questionnaire | No | — | +1/0/0 | +1 |
Basualdo et al. |
Descriptive study in one town of Argentina | 2002 | All age groups (n.s.) | A | A.l.; T.t. | 2×2 table |
Mod. T-L (five samples) | n.s. | n.s. | n.s. | — | +2/0/0 | +2 |
Belo et al. |
Descriptive study in three schools in Sao Tomé | 2000 | Sc (random) | U | A.l.; T.t. | OR (UVA) | K-K; T-L | n.s. | Questionnaire | n.s. | — | +2/0/0 | +2 |
Chongsuvivatwong et al. |
Descriptive study in four villages in Thailand | n.s. | All >6 y (random HH) | U | Hw | 2×2 table | K-K | n.s. | Questionnaire | Yes | Spent 11 mo prior to study to establish good relationship | +1/+1/+1 | +3 |
Corrales et al. |
Case-control study in eight communities in El Salvador | n.s. | All age groups (random HH; all solar latrine owners) | A | A.l.; T.t.; Hw | OR (MVA) | Mod. RFEC | n.s. | n.s. | n.s. | — | +1/0/0 | +1 |
de Souza et al. |
Descriptive study in two villages in Brazil | 2004 | All age groups (all) | A | STH; A.l.; T.t.; Hw | 2×2 table |
SS | No | Questionnaire | No | — | +1/0/0 | +1 |
Ensink et al. |
Descriptive study in four communities in Pakistan | 2002 | Adult men and children (only textile laborers, wastewater farmers, farmers) | A | STH; A.l.; T.t.; Hw | 2×2 table |
FES | n.s. | n.s. | n.s. | Only high-risk groups | +1/0/−1 | 0 |
Erlanger et al. |
Descriptive study in 17 villages in Lao People's Democratic Republic | 2001/2002 | All age groups (random) | A | STH; A.l.; T.t.; Hw | 2×2 table |
FES | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Gloor et al. |
Descriptive study in eight schools in the US | 1968 | Sc (all) | A | STH; Hw | 2×2 table | ZSF | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Gunawardena et al. |
Descriptive study in one village in Sri Lanka | 2000 | All >2 y (random HH, participants) | A | A.l.; T.t. |
2×2 table |
K-K | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Gunawardena et al. |
Descriptive study in two plantations in Sri Lanka | 2000 | All age groups (n.s.) | A | Hw | 2×2 table |
K-K | n.s. | Questionnaire | No | — | +1/0/0 | +1 |
Hagel et al. |
Descriptive study in an urban slum in Venezuela | 1993 | Children (representing overall socio-economic structure) | A | A.l.; T.t. | 2×2 table | Stoll | n.s. | Prior door-to-door interviews | n.s. | — | +1/0/0 | +1 |
Holland et al. |
Descriptive study in one health center in Panama | 1983 | PSc (random) | A | A.l.; T.t.; Hw | 2×2 table | n.s. | n.s. | Questionnaire (with mother or caregiver of child) | n.s. | — | +1/0/0 | +1 |
Ilechukwu et al. |
Descriptive study in three nurseries and three schools in Nigeria | 2003 | PSc, Sc (random) | U | STH; A.l.; T.t.; Hw | 2×2 table | K-K | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Jombo et al. |
Descriptive study in three communities in Nigeria | 2004 | All age groups (random) | A | STH; A.l.; T.t.; Hw | 2×2 table |
Mod. DS | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Kightlinger et al. |
Descriptive study in southeast Madagascar | n.s. | Children (n.s.) | U | A.l. | 2×2 table | FES | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Knopp et al. |
Descriptive study in two communities in Zanzibar | 2008 | All age groups (all adults; first 100 children) | A | STH; A.l.; T.t.; Hw | 2×2 table |
K-K, BM, KAP | 10% of stool samples | Questionnaire | n.s. | — | +3/0/0 | +3 |
Matthys et al. |
Descriptive study in six communities in Côte d'Ivoire | 2004 | All age groups (all farmers; non-farmers: random) | U | Hw | 2×2 table |
FEC, K-K (two slides) | 10% of stool samples | Questionnaire | n.s. | — | +3/0/0 | +3 |
Morales-Espinoza et al. |
Descriptive study in 32 communities in Mexico | 1998 | Children (systematic) | A | A.l. | OR (UVA) | Faust (three samples) | n.s. | Questionnaire | n.s. | — | +2/0/0 | +2 |
Nguyen et al. |
Descriptive study among women of reproductive age in Viet Nam | 1995 | Women (random cluster sampling) | U | A.l.; T.t.; Hw | 2×2 table | K-K | n.s. | Questionnaire | n.s. | Only data from closed latrine vs. “bush,” since open latrine not clearly defined | +1/0/0 | +1 |
Nishiura et al. |
Descriptive study in five schools in Pakistan | 2000 | Sc (random) | U | A.l. | 2×2 table | K-K (one stool) | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Olsen et al. |
Descriptive study in three villages in Kenya | 1994 | All age groups (all >4 y) | A | A.l.; Hw | 2×2 table | K-K (two stools, two slides) | n.s. | Questionnaire | n.s. | — | +2/0/0 | +2 |
Raja'a et al. |
Descriptive study in one town in Yemen | n.s. | Sc (random) | U | STH | 2×2 table | Mod. K-K | n.s. | Questionnaire | No | — | +1/0/0 | +1 |
Steinmann et al. |
Descriptive study in 51 schools in Kyrgyzstan | 2009 | Sc (random) | U | A.l. | Cal. | K-K (two slides) | n.s. | Questionnaire | n.s. | Toilet use during the night | +1/0/−1 | 0 |
Stephenson et al. |
Intervention study in two villages in Kenya | 1975–1980 | Sc, PSc (all) | A | A.l. | Cal. | Mod. T-L | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Stothard et al. |
Descriptive study in ten villages in Zanzibar | 2006 | Mothers and children (n.s.) | A | STH; A.l.; T.t.; Hw | 2×2 table |
K-K (one slide) | 10% of stool samples | Questionnaire | n.s. | — | +2/0/0 | +2 |
Sun et al. |
Descriptive study in three counties in China | 2003 | All age groups (random) | A | STH | 2×2 table | Mod. K-K | n.s. | n.s. | n.s. | — | +1/0/0 | +1 |
Toma et al. |
Descriptive study in four villages in Indonesia | 1994 | All age groups (random HH) | A | A.l.; T.t.; Hw | 2×2 table | Mod. K-K (Hw: mod. H-M) | n.s. | Questionnaire | No | — | +1/0/0 | +1 |
Torres et al. |
Descriptive study in six schools in Chile | 1993 | Sc (all) | A | A.l.; T.t. | 2×2 table | PAFS | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Trang et al. |
Descriptive study in two communities in Viet Nam | 2003 | Adults (random HH; exclusion of farmers) | A | STH; A.l.; T.t.; Hw | 2×2 table |
DS | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Trang et al. |
Descriptive study in a peri-urban area in Viet Nam | 2002 | All age groups (random HH) | A | STH; A.l.; T.t.; Hw | 2×2 table |
DS (one stool) | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Traub et al. |
Descriptive study in three communities in India | 2000 | All age groups (random HH) | U | A.l.; T.t.; Hw | Cal. | SS (one stool) | n.s. | Questionnaire | n.s. | Always the same interviewer | +1/0/+1 | +2 |
Ugbomoiko et al. |
Descriptive study in one village in Nigeria | 2005 | Children (random HH) | A | A.l. | 2×2 table | K-K (one sample) | n.s. | Questionnaire | n.s. | — | +1/0/0 | +1 |
Wördemann et al. |
Descriptive study in two municipalities (19 schools) in Cuba | 2003 | Sc (all) | U | A.l.; T.t.; Hw | OR (UVA) | DS, K-K (two slides) | n.s. | Questionnaire | n.s. | — | +2/0/0 | +2 |
Yajima et al. |
Descriptive study in one community in Viet Nam | 2007 | All age groups (random participant) | A | A.l.; T.t.; Hw | 2×2 table | K-K (two slides) | n.s. | Questionnaire | n.s. | Small sample size (only three with no latrine) | +1/0/−1 | 0 |
Data provided by author.
A.l.,
The diagnostic technique utilized for assessing soil-transmitted helminth infection status was mentioned in all the studies meeting our inclusion criteria. The Kato-Katz technique
Data are presented separately for availability and use of sanitation. Rectangles indicate ORs, and sizes of the rectangles represent the weight given to each study in the meta-analysis; open diamonds and vertical dashed lines indicate combined ORs; and horizontal lines indicate 95% CIs. Data are presented separately for aonly pit latrine, bonly solar urine-diverting desiccating latrine, conly adults, donly children. N.A., not assessed.
Data are presented separately for availability and use of sanitation. Rectangles indicate ORs, and sizes of the rectangles represent the weight given to each study in the meta-analysis; open diamonds and vertical dashed lines indicate combined ORs; and horizontal lines indicate 95% CIs. Data are presented separately for aonly pit latrine, bonly solar urine-diverting desiccating latrine, conly adults, donly children. N.A., not assessed.
Data are presented separately for availability and use of sanitation. Rectangles indicate ORs, and sizes of the rectangles represent the weight given to each study in the meta-analysis; open diamonds and vertical dashed lines indicate combined ORs; and horizontal lines indicate 95% CIs. Data are presented separately for aonly pit latrine, bonly solar urine-diverting desiccating latrine, conly adults, donly children. N.A., not assessed.
Data are presented separately for availability and use of sanitation. Rectangles indicate ORs, and sizes of the rectangles represent the weight given to each study in the meta-analysis; open diamonds and vertical dashed lines indicate combined ORs; and horizontal lines indicate 95% CIs. Data are presented separately for aonly adults and bonly children.
Characteristics |
|
|
Hookworm | Soil-Transmitted Helminths Combined | ||||||||
|
Random Effects Pooled OR (95% CI) |
|
Random Effects Pooled OR (95% CI) |
|
Random Effects Pooled OR (95% CI) |
|
Random Effects Pooled OR (95% CI) | |||||
Overall | 32 | 0.54 (0.43, 0.69) | 80.7 | 24 | 0.58 (0.45, 0.75) | 69.4 | 24 | 0.60 (0.48, 0.75) | 71.0 | 15 | 0.51 (0.44, 0.61) | 35.5 |
Only availability | 24 | 0.46 (0.33, 0.64) | 81.2 | 19 | 0.56 (0.46, 0.70) | 20.5 | 19 | 0.58 (0.45, 0.76) | 65.8 | 13 | 0.49 (0.40, 0.60) | 33.3 |
Only use | 8 | 0.78 (0.60, 1.00) | 56.1 | 5 | 0.54 (0.28, 1.02) | 90.5 | 5 | 0.63 (0.37, 1.05) | 79.1 | 2 | 0.56 (0.34, 0.92) | N.A. |
All age groups | 16 | 0.61 (0.43, 0.80) | 68.2 | 16 | 0.69 (0.49, 0.98) | 71.5 | 18 | 0.70 (0.54, 0.90) | 71.8 | 9 | 0.60 (0.51, 0.70) | 0.0 |
Only children | 16 | 0.46 (0.30, 0.71) | 86.0 | 8 | 0.47 (0.37, 0.60) | 14.3 | 6 | 0.35 (0.21, 0.57) | 51.5 | 6 | 0.39 (0.26, 0.59) | 66.7 |
Africa | 12 | 0.41 (0.22, 0.77) | 89.0 | 7 | 0.44 (0.32, 0.59) | 0 | 8 | 0.77 (0.51, 1.17) | 60.0 | 6 | 0.46 (0.35, 0.60) | 14.7 |
Asia | 11 | 0.57 (0.43, 0.77) | 77.3 | 9 | 0.66 (0.41, 1.05) | 82.7 | 10 | 0.62 (0.45, 0.86) | 74.4 | 6 | 0.64 (0.55, 0.75) | 0 |
Central and South America | 9 | 0.67 (0.48, 0.96) | 34.3 | 8 | 0.58 (0.43, 0.79) | 14.3 | 5 | 0.42 (0.22, 0.78) | 62.3 | 2 | 0.41 (0.24, 0.69) | N.A. |
US | 0 | 0 | 1 | 0.24 (0.10, 0.58) | N.A. | 1 | 0.26 (0.13, 0.50) | N.A. |
N.A., not assessed.
The 36 publications identified included 32 datasets on the effect of sanitation on infection with
Twenty-eight datasets were identified that specifically examined the relationship between availability of sanitation facilities and the prevalence of infection with soil-transmitted helminths. Among these, 24 reported data on
Use of sanitation facilities was reported in 11 publications. Stratified by soil-transmitted helminth species, meta-analyses included eight studies for
Results from different sub-group analyses are summarized in
Since the International Drinking Water Supply and Sanitation Decade (1980–1990), adequate sanitation, safe drinking water, and appropriate hygiene have been forgotten pillars of health, until recently
In our meta-analysis we found that the availability and use of sanitation facilities were associated with a reduction in the prevalence of infection with soil-transmitted helminths. Considering all of the studies that met our inclusion criteria, summary ORs ranging between 0.54 and 0.60 for the three common soil-transmitted helminth species were found. Similar estimates were obtained when studies were stratified by availability (ORs between 0.46 and 0.58)
Our findings revealed a somewhat stronger negative association of lack of sanitation with infection with soil-transmitted helminths than previous general reviews in which the introduction of water supply and/or sanitation interventions was associated with a reduction in the prevalences of
We adhered to the MOOSE guidelines for reporting meta-analysis of observational studies (see
Another aspect worth mentioning is that availability, access, ownership, and use of sanitation facilities are not one and the same. Indeed, availability of sanitation facilities does not automatically mean that people use them
Finally, in most of the included studies the type of sanitation facilities available or used was not mentioned, but such information is important, as the types of sanitation might be differentially associated with the prevalence of infection with different soil-transmitted helminth species
There were no randomized controlled trials evaluating the impact of sanitation facilities on the prevalence of infection with soil-transmitted helminths identified in our systematic review. Although randomized controlled trials provide the most robust evidence
The results of our meta-analysis reveal that sanitation is associated with a reduction in the prevalence of soil-transmitted helminth infections. Our findings, therefore, underscore what the Rockefeller Sanitary Commission stated more than 70 years ago: “Cure alone is almost useless in stamping out hookworm disease, because the patient can go out and immediately pick up more hookworms. The cure should be accompanied by a sanitation campaign for the prevention of soil pollution”
Details of all the publications that were fully screened by the first two authors (n = 162). Reasons why studies have been excluded are given (n = 126). Studies included in our metaanalysis are shaded grey (n = 36).
(DOC)
PRISMA checklist.
(DOC)
Study protocol for systematic review and meta-analysis to determine the effect of sanitation on soil-transmitted helminth infection.
(DOC)
We are grateful to all authors who kindly provided supplementary data for our analyses. We thank Rebekka Hirsbrunner and Thomas Fürst for their help in obtaining relevant articles, and Dr. Jan Hattendorf for statistical support. Maiti Laserna de Himpsl, Olga Gorlanova, and Shan Lv are acknowledged for translating (potentially) relevant articles from Spanish, Russian, and Chinese into English.
confidence interval
odds ratio