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Environmental Research Jul 2022Pollution of water sources, largely from wide-scale agricultural fertilizer use has resulted in nitrate and nitrite contamination of drinking water. The effects on human... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Pollution of water sources, largely from wide-scale agricultural fertilizer use has resulted in nitrate and nitrite contamination of drinking water. The effects on human health of raised nitrate and nitrite levels in drinking water are currently unclear.
OBJECTIVES
We conducted a systematic review of peer-reviewed literature on the association of nitrate and nitrite in drinking water with human health with a specific focus on cancer.
METHODS
We searched eight databases from 1 January 1990 until 28 February 2021. Meta-analyses were conducted when studies had the same exposure metric and outcome.
RESULTS
Of 9835 studies identified in the literature search, we found 111 studies reporting health outcomes, 60 of which reported cancer outcomes (38 case-control studies; 12 cohort studies; 10 other study designs). Most studies were set in the USA (24), Europe (20) and Taiwan (14), with only 3 studies from low and middle-income countries. Nitrate exposure in water (59 studies) was more commonly investigated than nitrite exposure (4 studies). Colorectal (15 studies) and gastric (13 studies) cancers were the most reported. In meta-analyses (4 studies) we identified a positive association of nitrate exposure with gastric cancer, OR = 1.91 (95%CI = 1.09-3.33) per 10 mg/L increment in nitrate ion. We found no association of nitrate exposure with colorectal cancer (10 studies; OR = 1.02 [95%CI = 0.96-1.08]) or cancers at any other site.
CONCLUSIONS
We identified an association of nitrate in drinking water with gastric cancer but with no other cancer site. There is currently a paucity of robust studies from settings with high levels nitrate pollution in drinking water. Research into this area will be valuable to ascertain the true health burden of nitrate contamination of water and the need for public policies to protect human health.
Topics: Drinking Water; Humans; Nitrates; Nitrites; Nitrogen Oxides; Stomach Neoplasms
PubMed: 35217009
DOI: 10.1016/j.envres.2022.112988 -
Lancet (London, England) Jul 2022Estimates of the effectiveness of water, sanitation, and hygiene (WASH) interventions that provide high levels of service on childhood diarrhoea are scarce. We aimed to... (Meta-Analysis)
Meta-Analysis
Effectiveness of interventions to improve drinking water, sanitation, and handwashing with soap on risk of diarrhoeal disease in children in low-income and middle-income settings: a systematic review and meta-analysis.
BACKGROUND
Estimates of the effectiveness of water, sanitation, and hygiene (WASH) interventions that provide high levels of service on childhood diarrhoea are scarce. We aimed to provide up-to-date estimates on the burden of disease attributable to WASH and on the effects of different types of WASH interventions on childhood diarrhoea in low-income and middle-income countries (LMICs).
METHODS
In this systematic review and meta-analysis, we updated previous reviews following their search strategy by searching MEDLINE, Embase, Scopus, Cochrane Library, and BIOSIS Citation Index for studies of basic WASH interventions and of WASH interventions providing a high level of service, published between Jan 1, 2016, and May 25, 2021. We included randomised and non-randomised controlled trials conducted at household or community level that matched exposure categories of the so-called service ladder approach of the Sustainable Development Goal (SDG) for WASH. Two reviewers independently extracted study-level data and assessed risk of bias using a modified Newcastle-Ottawa Scale and certainty of evidence using a modified Grading of Recommendations, Assessment, Development, and Evaluation approach. We analysed extracted relative risks (RRs) and 95% CIs using random-effects meta-analyses and meta-regression models. This study is registered with PROSPERO, CRD42016043164.
FINDINGS
19 837 records were identified from the search, of which 124 studies were included, providing 83 water (62 616 children), 20 sanitation (40 799 children), and 41 hygiene (98 416 children) comparisons. Compared with untreated water from an unimproved source, risk of diarrhoea was reduced by up to 50% with water treated at point of use (POU): filtration (n=23 studies; RR 0·50 [95% CI 0·41-0·60]), solar treatment (n=13; 0·63 [0·50-0·80]), and chlorination (n=25; 0·66 [0·56-0·77]). Compared with an unimproved source, provision of an improved drinking water supply on premises with higher water quality reduced diarrhoea risk by 52% (n=2; 0·48 [0·26-0·87]). Overall, sanitation interventions reduced diarrhoea risk by 24% (0·76 [0·61-0·94]). Compared with unimproved sanitation, providing sewer connection reduced diarrhoea risk by 47% (n=5; 0·53 [0·30-0·93]). Promotion of handwashing with soap reduced diarrhoea risk by 30% (0·70 [0·64-0·76]).
INTERPRETATION
WASH interventions reduced risk of diarrhoea in children in LMICs. Interventions supplying either water filtered at POU, higher water quality from an improved source on premises, or basic sanitation services with sewer connection were associated with increased reductions. Our results support higher service levels called for under SDG 6. Notably, no studies evaluated interventions that delivered access to safely managed WASH services, the level of service to which universal coverage by 2030 is committed under the SDG.
FUNDING
WHO, Foreign, Commonwealth & Development Office, and National Institute of Environmental Health Sciences.
Topics: Child; Diarrhea; Drinking Water; Hand Disinfection; Humans; Sanitation; Soaps
PubMed: 35780792
DOI: 10.1016/S0140-6736(22)00937-0 -
Maternal & Child Nutrition Oct 2018Child stunting reduction is the first of 6 goals in the Global Nutrition Targets for 2025 and a key indicator in the second Sustainable Development Goal of Zero Hunger....
Child stunting reduction is the first of 6 goals in the Global Nutrition Targets for 2025 and a key indicator in the second Sustainable Development Goal of Zero Hunger. The prevalence of child stunting in Indonesia has remained high over the past decade, and at the national level is approximately 37%. It is unclear whether current approaches to reduce child stunting align with the scientific evidence in Indonesia. We use the World Health Organization conceptual framework on child stunting to review the available literature and identify what has been studied and can be concluded about the determinants of child stunting in Indonesia and where data gaps remain. Consistent evidence suggests nonexclusive breastfeeding for the first 6 months, low household socio-economic status, premature birth, short birth length, and low maternal height and education are particularly important child stunting determinants in Indonesia. Children from households with both unimproved latrines and untreated drinking water are also at increased risk. Community and societal factors-particularly, poor access to health care and living in rural areas-have been repeatedly associated with child stunting. Published studies are lacking on how education; society and culture; agriculture and food systems; and water, sanitation, and the environment contribute to child stunting. This comprehensive synthesis of the available evidence on child stunting determinants in Indonesia outlines who are the most vulnerable to stunting, which interventions have been most successful, and what new research is needed to fill knowledge gaps.
Topics: Adolescent; Adult; Body Height; Child; Child, Preschool; Feeding Behavior; Growth Charts; Growth Disorders; Humans; Indonesia; Infant; Infant, Newborn; Mothers; Young Adult
PubMed: 29770565
DOI: 10.1111/mcn.12617 -
Reviews on Environmental Health Jun 2023Arsenic as a chemical is found in rock, soil, air and used in various industries and their products, such as colors, hairs, and fertilizers. Humans may be exposed to... (Review)
Review
OBJECT
Arsenic as a chemical is found in rock, soil, air and used in various industries and their products, such as colors, hairs, and fertilizers. Humans may be exposed to arsenic mainly through food and drinking water. Due to its adverse health effects, its presence in drinking water has become a public health concern.
METHODS
In this systematic review, we investigated the relationship between arsenic concentration in drinking water and the risk of kidney cancer in humans. For this reason, various electronic databases were searched from 1992 February to November 2021. In this review, three ecological studies, two case-control studies, and four cohort studies were investigated.
RESULTS
High levels of arsenic (100 μg/L) have been reported in many countries such as southwest Taiwan, Niigata, Argentine, and northern Chile. A significant relationship was observed between kidney cancer incidence and its mortality rate with high arsenic levels in drinking water.
CONCLUSIONS
Despite the limitations in some previous studies, reviewing and comparing the data of different regions indicates a scientific relationship between kidney cancer incidence and high concentrations of arsenic in drinking water.
Topics: Humans; Arsenic; Drinking Water; Water Pollutants, Chemical; Kidney Neoplasms; Incidence; Environmental Exposure
PubMed: 35286785
DOI: 10.1515/reveh-2021-0168 -
Archives of Environmental &... 2022Nitrate is an inorganic compound that occurs naturally in all surface and groundwater, although higher concentrations tend to occur only where fertilizers are used on... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Nitrate is an inorganic compound that occurs naturally in all surface and groundwater, although higher concentrations tend to occur only where fertilizers are used on the land. The regulatory limit for nitrate in public drinking water supplies was set to protect against infant methemoglobinemia, but other health effects were not considered. Risk of specific cancers and congenital disabilities may be increased when the nitrate is ingested, and nitrate is reduced to nitrite, which can react with amines and amides by nitrosation to form N-nitroso compounds which are known animal carcinogens. This study aims to evaluate the association between nitrate ingested through drinking water and the risk of developing cancers in humans.
METHODS
We performed a systematic review following PRISMA and MOOSE guidelines. A literature search was performed using PubMed, EMBASE, the Cochrane Library databases, Web of Science and Google Scholars in the time-frame from their inception to January 2020, for potentially eligible publications. STATA version 12.0 was used to conduct meta-regression and a two-stage meta-analysis.
RESULTS
A total of 48 articles with 13 different cancer sites were used for analysis. The meta-regression analysis showed stomach cancer had an association with the median dosage of nitrate from drinking water (t = 3.98, p = 0.0001, and adjusted R-squared = 50.61%), other types of cancers didn't show any association. The first stage of meta-analysis showed there was an association only between the risk of brain cancer & glioma (OR = 1.15, 95% CI: 1.06, 1.24) and colon cancer (OR = 1.11, 95% CI: 1.04, 1.17) and nitrate consumption in the analysis comparing the highest ORs versus the lowest. The 2 stage showed there was an association only between the risk colon cancer (OR = 1.14, 95% CI: 1.04, 1.23) and nitrate consumption in the analysis comparing all combined higher ORs versus the lowest.
CONCLUSION
This study showed that there is an association between the intake of nitrate from drinking water and a type of cancer in humans. The effective way of controlling nitrate concentrations in drinking water is the prevention of contamination (water pollution). Further research work on this topic is needed.
Topics: Drinking Water; Humans; Neoplasms; Nitrates; Risk; Water Pollutants, Chemical; Water Supply
PubMed: 33138742
DOI: 10.1080/19338244.2020.1842313 -
Fluoride exposure and cognitive neurodevelopment: Systematic review and dose-response meta-analysis.Environmental Research Mar 2023Many uncertainties still surround the possible harmful effect of fluoride exposure on cognitive neurodevelopment in children. The aim of this systematic review and... (Meta-Analysis)
Meta-Analysis Review
Many uncertainties still surround the possible harmful effect of fluoride exposure on cognitive neurodevelopment in children. The aim of this systematic review and meta-analysis was to characterize this relation through a dose-response approach, by comparing the intelligence quotient (IQ) scores in the highest versus the lowest fluoride exposure category with a random-effects model, within a one-stage dose-response meta-analysis based on a cubic spline random-effects model. Out of 1996 potentially relevant literature records, 33 studies were eligible for this review, 30 of which were also suitable for meta-analysis. The summary mean difference of IQ score, comparing highest versus lowest fluoride categories and considering all types of exposure, was -4.68 (95% confidence interval-CI -6.45; -2.92), with a value of -5.60 (95% CI -7.76; -3.44) for drinking water fluoride and -3.84 (95% CI -7.93; 0.24) for urinary fluoride. Dose-response analysis showed a substantially linear IQ decrease for increasing water fluoride above 1 mg/L, with -3.05 (95% CI -4.06; -2.04) IQ points per 1 mg/L up to 2 mg/L, becoming steeper above such level. A weaker and substantially linear decrease of -2.15 (95% CI -4.48; 0.18) IQ points with increasing urinary fluoride emerged above 0.28 mg/L (approximately reflecting a water fluoride content of 0.7 mg/L). The inverse association between fluoride exposure and IQ was particularly strong in the studies at high risk of bias, while no adverse effect emerged in the only study judged at low risk of bias. Overall, most studies suggested an adverse effect of fluoride exposure on children's IQ, starting at low levels of exposure. However, a major role of residual confounding could not be ruled out, thus indicating the need of additional prospective studies at low risk of bias to conclusively assess the relation between fluoride exposure and cognitive neurodevelopment.
Topics: Child; Humans; Fluorides; Intelligence; Prospective Studies; Drinking Water; Cognition
PubMed: 36639015
DOI: 10.1016/j.envres.2023.115239 -
Biological Trace Element Research Jan 2023Iodine is a micronutrient essential for maintaining normal body functioning, and the consumption depends on the distribution in the environment, and insufficient or... (Meta-Analysis)
Meta-Analysis Review
Iodine is a micronutrient essential for maintaining normal body functioning, and the consumption depends on the distribution in the environment, and insufficient or excessive intake results in thyroid dysfunction. The purpose of this review was to evaluate the correlation between iodine concentration in drinking water and the iodine status of the population. The systematic review was conducted following the PRISMA guidelines and was registered at the International Prospective Register of Ongoing Systematic Reviews (CRD42019128308). A literature search was conducted using MEDLINE/PUBMED (National Library of Medicine), LILACS (Latin-American and Caribbean Literature on Health Sciences), and Cochrane Library, June 2021. The quality of the studies was assessed by a checklist for cross-sectional studies developed by Joanna Briggs Institute. The initial search identified 121 articles, out of which ten were included in this systematic review, and five were included in the meta-analysis. Among the articles listed, six adopted cutoff points to classify the iodine content in the drinking water. The study identified median iodine concentration in drinking water from 2.2 to 617.8 μg/L and the correlation between iodine concentration in drinking water and urinary iodine concentration was 0.92, according to meta-analysis. Furthermore, the iodine status was correlated to the iodine content in water. The determination of a cutoff point can contribute to the implementation of iodine consumption control measures.
Topics: Humans; Iodine; Drinking Water; Goiter; Cross-Sectional Studies; Nutritional Status
PubMed: 35075595
DOI: 10.1007/s12011-022-03127-4 -
Reviews on Environmental Health Sep 2021Heavy metals in drinking water can threat human health and may induce several diseases. The association between heavy metals exposure and chronic kidney disease (CKD)...
Heavy metals in drinking water can threat human health and may induce several diseases. The association between heavy metals exposure and chronic kidney disease (CKD) has been indicated by few epidemiological studies. We conducted a systematic review of the epidemiologic publications of the association between exposure to heavy metals through drinking water and CKD. Keywords related to heavy metals and kidney diseases on MeSH were identified and searched in PubMed, Google Scholar, Scopus, Ovid-Medline and Web of Science until July 2020. 14 publications met our inclusion criteria and included in the current review. The included articles were conducted on the association between arsenic, cadmium, lead and chromium in drinking water and CKD. Our study could not find strong evidence between heavy exposure to through drinking water and CKD, except for arsenic. The negative association was found between arsenic and lead and glomerular filtration rate (eGFR). The positive correlation was observed between cadmium exposure and urinary N-acetyl--d-glucosaminidase (NAG) concentrations, and also arsenic and chromium exposure and kidney injury molecule (KIM-1). Assessment of studies showed an association between arsenic, cadmium, lead and chromium and albuminuria and proteinuria, without CKD outcomes. Current systematic study showed few evidence for exposure to arsenic, cadmium, lead and chromium through drinking water and incidence of kidney problems. However, more epidemiological studies are required to confirm this association.
Topics: Arsenic; Biomarkers; Drinking Water; Humans; Kidney; Metals, Heavy; Renal Insufficiency, Chronic; Water Pollutants, Chemical
PubMed: 33128529
DOI: 10.1515/reveh-2020-0110 -
Archives of Environmental &... May 2017We summarized epidemiological studies assessing sodium in drinking water and changes in blood pressure or hypertension published in English from 1960 to 2015 from... (Meta-Analysis)
Meta-Analysis Review
We summarized epidemiological studies assessing sodium in drinking water and changes in blood pressure or hypertension published in English from 1960 to 2015 from PubMed, Scopus, and Web of Science. We extracted data on blood pressure level or prevalence of hypertension and calculated pooled estimates using an inverse variance weighted random-effects model. The pooled standardized mean difference (SMD) in 7 studies (12 data sets) comparing the low and high water sodium exposure groups for systolic blood pressure (SBP) was 0.08 (95% CI, -0.17 to 0.34) and for diastolic blood pressure (DBP) was 0.23 (95% CI, 0.09-0.36). Of the 3 studies that assessed the association between high water sodium and odds of hypertension, 2 recent studies showed consistent findings of higher risk of hypertension. Our systematic review suggests an association between water sodium and human blood pressure (more consistently for DBP) but remain inconclusive because of the small number of studies (largely in young populations) and the cross-sectional design and methodological drawbacks. In the context of climate-change-related sea level rise and increasing saltwater intrusion into drinking water sources, further research is urgently warranted to investigate and guide intervention in this increasingly widespread problem.
Topics: Drinking Water; Humans; Hypertension; Risk Assessment; Salinity
PubMed: 27064986
DOI: 10.1080/19338244.2016.1175413 -
The Cochrane Database of Systematic... Sep 2022Although various solutions have been recommended for cleansing wounds, normal saline is favoured as it is an isotonic solution and is not thought to interfere with the... (Review)
Review
BACKGROUND
Although various solutions have been recommended for cleansing wounds, normal saline is favoured as it is an isotonic solution and is not thought to interfere with the normal healing process. Tap water is commonly used in community settings for cleansing wounds because it is easily accessible, efficient and cost-effective; however, there is an unresolved debate about its use.
OBJECTIVES
To assess the effects of water for wound cleansing.
SEARCH METHODS
For this fifth update, in May 2021 we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.
SELECTION CRITERIA
We included all randomised controlled trials (RCTs) that assessed wound cleansing using different types of water (e.g. tap water, distilled, boiled) compared with no cleansing or with other solutions (e.g. normal saline). For this update, we excluded quasi-RCTs, thereby removing some studies which had been included in the previous version of the review.
DATA COLLECTION AND ANALYSIS
Two review authors independently carried out trial selection, data extraction and GRADE assessment of the certainty of evidence.
MAIN RESULTS
We included 13 trials in this update including a total of 2504 participants ranging in age from two to 95 years. Participants in the trials experienced open fractures, surgical wounds, traumatic wounds, anal fissures and chronic wounds. The trials were conducted in six different countries with the majority conducted in India and the USA. Three trials involving 148 participants compared cleansing with tap water with no cleansing. Eight trials involving 2204 participants assessed cleansing with tap water compared with cleansing with normal saline. Two trials involving 152 participants assessed cleansing with distilled water compared with cleansing with normal saline. One trial involving 51 participants also assessed cleansing with cooled boiled water compared with cleansing with normal saline, and cleansing with distilled water compared with cleansing with cooled boiled water. Wound infection: no trials reported on wound infection for the comparison cleansing with tap water versus no cleansing. For all wounds, eight trials found the effect of cleansing with tap water compared with normal saline is uncertain (risk ratio (RR) 0.84, 95% confidence interval (CI) 0.59 to 1.19); very low-certainty evidence. Two trials comparing the use of distilled water with normal saline for cleansing open fractures found that the effect on the number of fractures that were infected is uncertain (RR 0.70, 95% CI 0.45 to 1.09); very low-certainty evidence. One trial compared the use of cooled boiled water with normal saline for cleansing open fractures and found that the effect on the number of fractures infected is uncertain (RR 0.83, 95% CI 0.37 to 1.87); very low-certainty evidence. This trial also compared the use of distilled water with cooled boiled water and found that the effect on the number of fractures infected is uncertain (RR 0.59, 95% CI 0.24 to 1.47); very low-certainty evidence. Wound healing: results from three trials comparing the use of tap water with no wound cleansing demonstrated there may be little or no difference in the number of wounds that did not heal between the groups (RR 1.04, 95% CI 0.95 to 1.14); low-certainty evidence. The effect of tap water compared with normal saline is uncertain; two trials were pooled (RR 0.57, 95% CI 0.30 to 1.07) but the certainty of the evidence is very low. Results from one study comparing the use of distilled water with normal saline for cleansing open fractures found that there may be little or no difference in the number of fractures that healed (RR could not be estimated, all wounds healed); the certainty of the evidence is low. Reduction in wound size: the effect of cleansing with tap water compared with normal saline on wound size reduction is uncertain (RR 0.97, 95% CI 0.56 to 1.68); the certainty of the evidence is very low. Rate of wound healing: the effect of cleansing with tap water compared with normal saline on wound healing rate is uncertain (mean difference (MD) -3.06, 95% CI -6.70 to 0.58); the certainty of the evidence is very low.
COSTS
two trials reported cost analyses but the cost-effectiveness of tap water compared with the use of normal saline is uncertain; the certainty of the evidence is very low. Pain: results from one study comparing the use of tap water with no cleansing for acute and chronic wounds showed that there may be little or no difference in pain scores. The certainty of the evidence is low. Patient satisfaction: results from one study comparing the use of tap water with no cleansing for acute and chronic wounds showed that there may be little or no difference in patient satisfaction. The certainty of evidence is low. The effect of cleansing with tap water compared with normal saline is uncertain as the certainty of the evidence is very low.
AUTHORS' CONCLUSIONS
All the evidence identified in the review was low or very low certainty. Cleansing with tap water may make little or no difference to wound healing compared with no cleansing; there are no data relating to the impact on wound infection. The effects of cleansing with tap water, cooled boiled water or distilled water compared with cleansing with saline are uncertain, as is the effect of distilled water compared with cooled boiled water. Data for other outcomes are limited across all the comparisons considered and are either uncertain or suggest that there may be little or no difference in the outcome.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; Drinking Water; Fractures, Open; Humans; Middle Aged; Pain; Saline Solution; Sodium Chloride; Therapeutic Irrigation; Wound Infection; Young Adult
PubMed: 36103365
DOI: 10.1002/14651858.CD003861.pub4