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1.
Eur J Orthop Surg Traumatol ; 34(2): 893-900, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37770594

RESUMO

PURPOSE: The primary goal of this study was to investigate whether superior humeral head osteophyte (SHO) size is associated with rotator cuff insufficiency, including rotator cuff tear (RCT), supraspinatus tendon thickness, and fatty infiltration of the rotator cuff muscles. METHODS: Patients ≥ 18 years who were diagnosed with glenohumeral osteoarthritis were retrospectively reviewed. SHO size was determined by radiograph. MRI measured SHO and RCT presence, type, and size; supraspinatus tendon thickness; and fatty infiltration of rotator cuff musculature. RESULTS: A total of 461 patients were included. Mean SHO size was 1.93 mm on radiographs and 2.13 mm on MRI. Risk ratio for a RCT was 1.14. For each 1-mm increase in SHO size on radiograph, supraspinatus tendon thickness decreased by 0.20 mm. SHO presence was associated with moderate-to-severe fatty infiltration of the supraspinatus with a risk ratio of 3.16. CONCLUSION: SHOs were not associated with RCT but were associated with higher risk of supraspinatus FI and decreased tendon thickness, which could indicate rotator cuff insufficiency. LEVEL OF EVIDENCE: IV.


Assuntos
Osteoartrite , Osteófito , Lesões do Manguito Rotador , Articulação do Ombro , Humanos , Manguito Rotador/diagnóstico por imagem , Cabeça do Úmero/diagnóstico por imagem , Osteófito/complicações , Osteófito/diagnóstico por imagem , Articulação do Ombro/diagnóstico por imagem , Lesões do Manguito Rotador/complicações , Lesões do Manguito Rotador/diagnóstico por imagem , Osteoartrite/complicações , Osteoartrite/diagnóstico por imagem
2.
Clin Kidney J ; 16(11): 2082-2090, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37915900

RESUMO

Background: Oral iron is the predominant route of iron replacement (IRT) but its benefits and safety are unclear in patients with chronic kidney disease (CKD). Methods: We examined the association of oral IRT vs no IRT with end-stage kidney disease (ESKD) and mortality in a national cohort of US Veterans. We identified 17 413 incident new users of oral IRT with estimated glomerular filtration rates <60 mL/min/1.73 m2 and 32 530 controls who did not receive any IRT during 2004-18. We used propensity score-overlap weighting to account for differences in key baseline characteristics associated with the use of oral IRT. We examined associations using competing risk regression and Cox models. Results: In the cohort of 49 943 patients, 1616 (3.2%) patients experienced ESKD and 28 711 (57%) patients died during a median follow-up of 1.9 years. Oral IRT was not associated with ESKD [subhazard ratio (HR) (95% confidence interval, CI) 1.00 (0.84-1.19), P = .9] and was associated with higher risk of all-cause mortality [HR (95% CI) 1.06 (1.01-1.11), P = .01]. There was significant heterogeneity of treatment effect for mortality, with oral IRT associated with higher mortality in the subgroups of patients without congestive heart failure (CHF), anemia or iron deficiency. In patient with blood hemoglobin <10 g/dL oral IRT was associated with significantly lower mortality. Conclusion: Oral IRT was associated with lower mortality only in patients with anemia. In patients without anemia, iron deficiency or CHF, the risk-benefit ratio of oral IRT should be further examined.

3.
Eur J Haematol ; 111(6): 872-880, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37668586

RESUMO

OBJECTIVE: We investigated the association of oral iron replacement with the incidence of chronic kidney disease (CKD) in a population with normal kidney function to study the effects of iron replacement on the development of new onset CKD. METHODS: In a national cohort of US Veterans with no pre-existing CKD, we identified 33 894 incident new users of oral iron replacement and a comparable group of 112 780 patients who did not receive any iron replacement during 2004-2018. We examined the association of oral iron replacement versus no iron replacement with the incidence of eGFR <60 mL/min/1.73 m2 and the incidence of urine albumin creatinine ratio (UACR) ≥30 mg/g in competing risk regressions and in Cox models. We used propensity score weighing to account for differences in key baseline characteristics associated with the use of oral iron replacement. RESULTS: In the cohort of 146 674 patients, a total of 18 547 (13%) patients experienced incident eGFR <60 mL/min/1.73 m2 , and 16 117 patients (11%) experienced new onset UACR ≥30 mg/g. Oral iron replacement was associated with significantly higher risk of incident eGFR <60 mL/min/1.73 m2 (subhazard ratio, 95% confidence interval [CI]: 1.3 [1.22-1.38], p < .001) and incident albuminuria (subhazard ratio, 95% CI: 1.14 [1.07-1.22], p < .001). CONCLUSION: Oral iron replacement is associated with higher risk of new onset CKD. The long-term kidney safety of oral iron replacement should be tested in clinical trials.


Assuntos
Insuficiência Renal Crônica , Humanos , Incidência , Creatinina , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/epidemiologia , Rim , Ferro/efeitos adversos , Taxa de Filtração Glomerular
4.
J Shoulder Elbow Surg ; 32(11): 2214-2221, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37348782

RESUMO

BACKGROUND: A corticosteroid flare reaction is a well-described phenomenon that causes significant pain and dysfunction. The paucity of literature impedes decision making regarding which corticosteroid to use for shoulder injection. The purpose of this study was to compare methylprednisolone acetate (MPA) and triamcinolone acetonide (TA) injections in the glenohumeral joint and/or subacromial space in terms of efficacy and the incidence of steroid flare reactions. METHODS: In this prospective, interrupted time series, parallel study, patients received injections in the glenohumeral joint and/or subacromial space. MPA and TA were used during 2 discrete 3-month periods. The injections consisted of 2 mL of lidocaine, 2 mL of bupivacaine, and 80 mg of either MPA or TA. Visual analog scale (VAS) pain scores were recorded immediately before injection; 1-7 days after injection; and 3, 6, and 12 months after injection. The primary outcome was the incidence of a steroid flare reaction, defined as a post-injection increase in the VAS score by ≥2 points. The secondary outcome was injection failure, defined as a post-injection VAS score greater than the baseline score or the need for another intervention. We used linear mixed models with a patient-level random intercept to identify the mean VAS score change for TA injections in the first week after injection. RESULTS: MPA or TA shoulder injections were administered in 421 patients; of these patients, 15 received bilateral-joint injections whereas 406 received a single-joint injection, for a total of 436 injections (209 MPA and 227 TA injections). Pain scores in the first week after injection were available for 193 MPA and 199 TA injections. Significantly more patients in the MPA cohort reported flare reactions compared with the TA cohort (22.8% vs. 4.0%, P < .001) during the first week after injection. In the first week after injection, the mean VAS score of patients receiving TA injections was 1.05 (95% confidence interval, 0.47-1.63) lower than that of patients receiving MPA injections when adjusted for age, sex, race, pain type, surgeon type, and injection site. At 3 months, surveys for 169 MPA and 172 TA injections were completed, with no significant difference in the rate of injection failure for MPA vs. TA (42.6% vs. 36.1%, P = .224). Treatment failure rates were significantly higher for MPA than for TA at 6 months (78.44% vs. 62.5%, P < .001) but not at 12 months (81.18% vs. 81.42%, P = .531.) CONCLUSION: TA injections resulted in a >5-fold reduction in steroid flare reactions, with statistically superior 6-month efficacy rates, compared with MPA injections. This study supports TA as a more viable corticosteroid option for shoulder injection.


Assuntos
Metilprednisolona , Triancinolona , Humanos , Metilprednisolona/efeitos adversos , Ombro , Estudos Prospectivos , Análise de Séries Temporais Interrompida , Corticosteroides/uso terapêutico , Acetato de Metilprednisolona , Injeções Intra-Articulares , Dor , Resultado do Tratamento
5.
J Am Heart Assoc ; 9(18): e014978, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32875927

RESUMO

Background We compared the relationship of past and contemporary sodium (Na) intake with cardiometabolic biomarkers. Methods and Results A total of 1191 participants' data from a randomized controlled trial in coastal Bangladesh were analyzed. Participants provided 24-hour urine Na (24UNa) data for 5 monthly visits. Their fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein, blood pressure, and 24-hour urine protein were measured at the fifth visit. Participants' mean 24UNa over the first 4 visits was the past Na, and 24UNa of the fifth visit was the contemporary Na intake. We estimated the prevalence ratios of elevated cardiometabolic biomarkers and metabolic syndrome across 24UNa tertiles by multilevel logistic regression using participant-, household-, and community-level random intercepts. Models were adjusted for age, sex, body mass index, smoking, physical activity, alcohol consumption, sleep hours, religion, and household wealth. Compared with participants in tertile 1 of past urine Na, those in tertile 3 had 1.46 (95% CI, 1.08-1.99) times higher prevalence of prediabetes or diabetes mellitus, 5.49 (95% CI, 2.73-11.01) times higher prevalence of large waist circumference, and 1.60 (95% CI, 1.04-2.46) times higher prevalence of metabolic syndrome. Compared with participants in tertile 1 of contemporary urine Na, those in tertile 3 had 1.93 (95% CI, 1.24-3.00) times higher prevalence of prediabetes or diabetes mellitus, 3.14 (95% CI, 1.45-6.83) times higher prevalence of proteinuria, and 2.23 (95% CI, 1.34-3.71) times higher prevalence of large waist circumference. Conclusions Both past and contemporary Na intakes were associated with higher cardiometabolic disease risk.


Assuntos
Fatores de Risco Cardiometabólico , Síndrome Metabólica/epidemiologia , Sódio na Dieta/administração & dosagem , Adulto , Bangladesh/epidemiologia , Biomarcadores , Glicemia/análise , Pressão Sanguínea , Colesterol/sangue , Feminino , Humanos , Lipoproteínas HDL/sangue , Modelos Logísticos , Masculino , Síndrome Metabólica/etiologia , Pessoa de Meia-Idade , Proteinúria/urina , Fatores de Risco , Sódio na Dieta/efeitos adversos , Triglicerídeos/sangue , Adulto Jovem
6.
J Am Heart Assoc ; 8(21): e013287, 2019 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-31615314

RESUMO

Background We compared the relationship between sodium (Na) intake and blood pressure when Na intake was estimated from first- and second-morning spot urine samples using the INTERSALT (International Study on Salt and Blood Pressure) formula, versus directly measured 24-hour samples. Methods and Results We collected 24-hour urine and first- and second-morning voids of 383 participants in coastal Bangladesh for 2 visits. We measured participants' blood pressure using an Omron® HEM-907 monitor. To assess the shape of the relationship between urinary Na and blood pressure, we created restricted cubic spline plots adjusted for age, sex, body mass index, smoking and alcohol consumption, physical activities, religion, sleep hours, and household wealth. To assess multicollinearity, we reported variance inflation factors, tolerances, and Leamer's and Klein's statistics following linear regression models. The mean daily urinary Na was 122 (SD 26) mmol/d for the first; 122 (SD 27) mmol/d for the second; and 134 (SD 70) mmol/d for the 24-hour samples. The restricted cubic spline plots illustrated no association between first-morning urinary Na and systolic blood pressure until the 90th percentile distribution followed by a downward relationship; a nonlinear inverse-V-shaped relationship between second-morning urinary Na and systolic blood pressure; and a monotonic upward relationship between 24-hour urinary Na and systolic blood pressure. We found no evidence of multicollinearity for the 24-hour urinary Na model. Conclusions The urinary Na and systolic blood pressure relationship varied for 3 urinary Na measurements. Twenty-four-hour urinary Na captured more variability of Na intake compared with spot urine samples, and its regression models were not affected by multicollinearity.


Assuntos
Pressão Sanguínea , Sódio na Dieta/urina , Coleta de Urina/métodos , Adulto , Bangladesh , Monitorização Ambulatorial da Pressão Arterial , Índice de Massa Corporal , Feminino , Humanos , Masculino , Fatores Sexuais , Sístole
7.
Artigo em Inglês | MEDLINE | ID: mdl-31261639

RESUMO

Background: We assessed the association of groundwater chemicals with systolic blood pressure (SBP) and diastolic blood pressure (DBP). Methods: Blood pressure data for ≥35-year-olds were from the Bangladesh Demographic and Health Survey in 2011. Groundwater chemicals in 3534 well water samples from Bangladesh were measured by the British Geological Survey (BGS) in 1998-1999. Participants who reported groundwater as their primary source of drinking water were assigned chemical measures from the nearest BGS well. Survey-adjusted linear regression methods were used to assess the association of each groundwater chemical with the log-transformed blood pressure of the participants. Models were adjusted for age, sex, body mass index, smoking status, geographical region, household wealth, rural or urban residence, and educational attainment, and further adjusted for all other groundwater chemicals. Results: One standard deviation (SD) increase in groundwater magnesium was associated with a 0.992 (95% confidence interval (CI): 0.986, 0.998) geometric mean ratio (GMR) of SBP and a 0.991 (95% CI: 0.985, 0.996) GMR of DBP when adjusted for covariates except groundwater chemicals. When additionally adjusted for groundwater chemicals, one SD increase in groundwater magnesium was associated with a 0.984 (95% CI: 0.972, 0.997) GMR of SBP and a 0.990 (95% CI: 0.979, 1.000) GMR of DBP. However, associations were attenuated following Bonferroni-correction for multiple chemical comparisons in the full-adjusted model. Groundwater concentrations of calcium, potassium, silicon, sulfate, barium, zinc, manganese, and iron were not associated with SBP or DBP in the full-adjusted models. Conclusions: Groundwater magnesium had a weak association with lower SBP and DBP of the participants.


Assuntos
Pressão Sanguínea , Água Subterrânea/química , Hipertensão/fisiopatologia , Adulto , Bangladesh , Índice de Massa Corporal , Estudos Transversais , Feminino , Humanos , Masculino
8.
J Am Heart Assoc ; 8(9): e012007, 2019 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-31060415

RESUMO

Background Sodium (Na+) in saline water may increase blood pressure ( BP ), but potassium (K+), calcium (Ca2+), and magnesium (Mg2+) may lower BP . We assessed the association between drinking water salinity and population BP . Methods and Results We pooled 6487 BP measurements from 2 cohorts in coastal Bangladesh. We used multilevel linear models to estimate BP differences across water salinity categories: fresh water (electrical conductivity, <0.7 mS/cm), mild salinity (electrical conductivity ≥0.7 and <2 mS/cm), and moderate salinity (electrical conductivity ≥2 and <10 mS/cm). We assessed whether salinity categories were associated with hypertension using multilevel multinomial logistic models. Models included participant-, household-, and community-level random intercepts. Models were adjusted for age, sex, body mass index ( BMI ), physical activity, smoking, household wealth, alcohol consumption, sleep hours, religion, and salt consumption. We evaluated the 24-hour urinary minerals across salinity categories, and the associations between urinary minerals and BP using multilevel linear models. Compared with fresh water drinkers, mild-salinity water drinkers had lower mean systolic BP (-1.55 [95% CI : -3.22-0.12] mm Hg) and lower mean diastolic BP (-1.26 [95% CI : -2.21--0.32] mm Hg) adjusted models. The adjusted odds ratio among mild-salinity water drinkers for stage 1 hypertension was 0.60 (95% CI : 0.43-0.84) and for stage 2 hypertension was 0.56 (95% CI : 0.46-0.89). Mild-salinity water drinkers had high urinary Ca2+, and Mg2+, and both urinary Ca2+ and Mg2+ were associated with lower BP. Conclusions Drinking mild-salinity water was associated with lower BP , which can be explained by higher intake of Ca2+ and Mg2+ through saline water.


Assuntos
Pressão Sanguínea , Cálcio/urina , Água Potável/análise , Hipertensão/fisiopatologia , Magnésio/urina , Eliminação Renal , Salinidade , Sódio/urina , Adulto , Idoso , Bangladesh/epidemiologia , Condutividade Elétrica , Feminino , Humanos , Hipertensão/epidemiologia , Hipertensão/prevenção & controle , Hipertensão/urina , Masculino , Pessoa de Meia-Idade , Fatores de Proteção , Fatores de Risco , Adulto Jovem
9.
Trials ; 19(1): 360, 2018 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-29976234

RESUMO

BACKGROUND: Researchers typically report more on the impact of public health interventions and less on the degree to which interventions were followed implementation fidelity. We developed and measured fidelity indicators for the WASH Benefits Bangladesh study, a large-scale efficacy trial, in order to identify gaps between intended and actual implementation. METHODS: Community health workers (CHWs) delivered individual and combined water, sanitation, handwashing (WSH) and child nutrition interventions to 4169 enrolled households in geographically matched clusters. Households received free enabling technologies (insulated water storage container; sani-scoop, potty, double-pit, pour-flush latrine; handwashing station, soapy-water storage bottle), and supplies (chlorine tablets, lipid-based nutrient supplements, laundry detergent sachets) integrated with parallel behavior-change promotion. Behavioral objectives were drinking treated, safely stored water, safe feces disposal, handwashing with soap at key times, and age-appropriate nutrition behaviors. We administered monthly surveys and spot-checks to households from randomly selected clusters for 6 months early in the trial. If any fidelity measures fell below set benchmarks, a rapid response mechanism was triggered. RESULTS: In the first 3 months, functional water seals were detected in 33% (14/42) of latrines in the sanitation only arm; 35% (14/40) for the combined WSH arm; and 60% (34/57) for the combined WSH and Nutrition arm, all falling below the pre-set benchmark of 80%. Other fidelity indicators met the 65 to 80% uptake benchmarks. Rapid qualitative investigations determined that households concurrently used their own latrines with broken water seals in parallel with those provided by the trial. In consultation with the households, we closed pre-existing latrines without water seals, increased the CHWs' visit frequency to encourage correct maintenance of latrines with water seals, and discouraged water-seal removal or breakage. At the sixth assessment, 86% (51/59) of households were in sanitation only; 92% (72/78) in the combined WSH; and 93% (71/76) in the combined WSH and Nutrition arms had latrines with functional water seals. CONCLUSIONS: An intensive implementation fidelity monitoring and rapid response system proved beneficial for this efficacy trial. To implement a routine program at scale requires further research into an adaptation of fidelity monitoring that supports program effectiveness. TRIAL REGISTRATION: WASH Benefits Bangladesh: ClinicalTrials.gov, ID: NCT01590095 . Registered on 30 April 2012.


Assuntos
Fenômenos Fisiológicos da Nutrição Infantil , Comportamentos Relacionados com a Saúde , Higiene , Saneamento , Qualidade da Água , Bangladesh , Criança , Desinfecção das Mãos , Humanos , Banheiros
10.
Trials ; 19(1): 359, 2018 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-29976247

RESUMO

BACKGROUND: Water, sanitation, and hygiene (WASH) efficacy trials deliver interventions to the target population under optimal conditions to estimate their effects on outcomes of interest, to inform subsequent selection for inclusion in routine programs. A systematic and intensive approach to intervention delivery is required to achieve the high-level uptake necessary to measure efficacy. We describe the intervention delivery system adopted in the WASH Benefits Bangladesh study, as part of a three-paper series on WASH Benefits Intervention Delivery and Performance. METHODS: Community Health Workers (CHWs) delivered individual and combined WASH and nutrition interventions to 4169 enrolled households in geographically matched clusters. Households were provided with free enabling technologies and supplies, integrated with parallel behaviour-change promotion. Behavioural objectives were drinking treated, safely stored water, safe feces disposal, handwashing with soap at key times, and age-appropriate nutrition behaviours (birth to 24 months). The intervention delivery system built on lessons learned from prior WASH intervention effectiveness, implementation, and formative research studies. We recruited local CHWs, residents of the study villages, through transparent merit-based selection methods, and consultation with community leaders. CHW supervisors received training on direct intervention delivery, then trained their assigned CHWs. CHWs in turn used the technologies in their own homes. Each CHW counseled six to eight intervention households spread across a 0.2-2.2-km radius, with a 1:12 supervisor-to-CHW ratio. CHWs met monthly with supervisor-trainers to exchange experiences and adapt technology and behaviour-change approaches to evolving conditions. Intervention uptake was tracked through fidelity measures, with a priori benchmarks necessary for an efficacy study. RESULTS: Sufficient levels of uptake were attained by the fourth intervention assessment month and sustained throughout the intervention period. Periodic internal CHW monitoring resulted in discontinuation of a small number of low performers. CONCLUSIONS: The intensive intervention delivery system required for an efficacy trial differs in many respects from the system for a routine program. To implement a routine program at scale requires further research on how to optimize the supervisor-to-CHW-to-intervention household ratios, as well as other program costs without compromising program effectiveness. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCC01590095 . Registered on 2 May 2012.


Assuntos
Comportamentos Relacionados com a Saúde , Higiene , Saneamento , Qualidade da Água , Bangladesh , Agentes Comunitários de Saúde , Características da Família , Desinfecção das Mãos , Humanos , Avaliação de Programas e Projetos de Saúde
11.
Trials ; 19(1): 358, 2018 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-29976251

RESUMO

BACKGROUND: Uptake matters for evaluating the health impact of water, sanitation and hygiene (WASH) interventions. Many large-scale WASH interventions have been plagued by low uptake. For the WASH Benefits Bangladesh efficacy trial, high uptake was a prerequisite. We assessed the degree of technology and behavioral uptake among participants in the trial, as part of a three-paper series on WASH Benefits Intervention Delivery and Performance. METHODS: This study is a cluster randomized trial comprised of geographically matched clusters among four districts in rural Bangladesh. We randomly allocated 720 clusters of 5551 pregnant women to individual or combined water, sanitation, handwashing, and nutrition interventions, or a control group. Behavioral objectives included; drinking chlorine-treated, safely stored water; use of a hygienic latrine and safe feces disposal at the compound level; handwashing with soap at key times; and age-appropriate nutrition behaviors (pregnancy to 24 months) including a lipid-based nutrition supplement (LNS). Enabling technologies and behavior change were promoted by trained local community health workers through periodic household visits. To monitor technology and behavioral uptake, we conducted surveys and spot checks in 30-35 households per intervention arm per month, over a 20-month period, and structured observations in 324 intervention and 108 control households, approximately 15 months after interventions commenced. RESULTS: In the sanitation arms, observed adult use of a hygienic latrine was high (94-97% of events) while child sanitation practices were moderate (37-54%). In the handwashing arms, handwashing with soap was more common after toilet use (67-74%) than nonintervention arms (18-40%), and after cleaning a child's anus (61-72%), but was still low before food handling. In the water intervention arms, more than 65% of mothers and index children were observed drinking chlorine-treated water from a safe container. Reported LNS feeding was > 80% in nutrition arms. There was little difference in uptake between single and combined intervention arms. CONCLUSIONS: Rigorous implementation of interventions deployed at large scale in the context of an efficacy trial achieved high levels of technology and behavioral uptake in individual and combined WASH and nutrition intervention households. Further work should assess how to achieve similar uptake levels under programmatic conditions. TRIAL REGISTRATION: WASH Benefits Bangladesh: ClinicalTrials.gov, identifier: NCT01590095 . Registered on April 30, 2012.


Assuntos
Fenômenos Fisiológicos da Nutrição Infantil , Comportamentos Relacionados com a Saúde , Higiene , Saneamento , Qualidade da Água , Adulto , Bangladesh , Criança , Feminino , Desinfecção das Mãos , Humanos , Gravidez
12.
Am J Trop Med Hyg ; 98(4): 977-983, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29436334

RESUMO

We assessed the ability of sodium dichloroisocyanurate (NaDCC) to provide adequate chlorine residual when used to treat groundwater with variable iron concentration. We randomly selected 654 tube wells from nine subdistricts in central Bangladesh to measure groundwater iron concentration and corresponding residual-free chlorine after treating 10 L of groundwater with a 33-mg-NaDCC tablet. We assessed geographical variations of iron concentration using the Kruskal-Wallis test and examined the relationships between the iron concentrations and chlorine residual by quantile regression. We also assessed whether user-reported iron taste in water and staining of storage vessels can capture the presence of iron greater than 3 mg/L (the World Health Organization threshold). The median iron concentration among measured wells was 0.91 (interquartile range [IQR]: 0.36-2.01) mg/L and free residual chlorine was 1.3 (IQR: 0.6-1.7) mg/L. The groundwater iron content varied even within small geographical regions. The median free residual chlorine decreased by 0.29 mg/L (95% confidence interval: 0.27, 0.33, P < 0.001) for every 1 mg/L increase in iron concentration. Owner-reported iron staining of the storage vessel had a sensitivity of 92%, specificity of 75%, positive predictive value of 41%, and negative predictive value of 98% for detecting > 3 mg/L iron in water. Similar findings were observed for user-reported iron taste in water. Our findings reconfirm that chlorination of groundwater that contains iron may result in low-level or no residual. User reports of no iron taste or no staining of storage containers can be used to identify low-iron tube wells suitable for chlorination. Furthermore, research is needed to develop a color-graded visual scale for iron staining that corresponds to different iron concentrations in water.


Assuntos
Cloro/química , Água Subterrânea/química , Ferro/análise , Triazinas/química , Bangladesh , Halogenação , Humanos , Comprimidos
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